CX20745 Low-Power I2S CODEC
Data Sheet
General Description
Features
The CX20745 is an Integrated Interchip Sound (I2S) audio
Coder-Decoder (CODEC), with integrated stereo class-D
speaker amplifiers and capless headphones with
performance that exceeds 100dB Signal-to-Noise Ratio
(SNR). Innovative Digital Signal Processing (DSP)
maximizes speaker loudness without distortion, performs
loudness compensation, and normalizes microphone
pick-up levels. Combined with Conexant’s software and
design support services, the CX20745 is an ideal turnkey
solution for tablets, ultrabooks, portable media players,
SMART phones, and digital docking stations.
•
The integrated filterless class-D stereo amplifier with
spread spectrum Electro-Magnetic Interference (EMI)
dispersion technology is capable of driving up to 2W RMS
per channel into 4 speakers. Built-in, fully configurable
hardware Equalizer (EQ) and Dynamic Range
Compression (DRC) improve frequency response,
maximize the output volume, and get best audio
performance from integrated speakers independent of the
driver and Operating System (OS).
A stereo pair of capless headphone drivers includes
integrated short circuit protection and auto-recovery.
These high performance headphone drivers save cost by
eliminating external headphone amplifiers and Direct
Current (DC) blocking capacitors. The capless
architecture outputs a full-range frequency response that
exceeds 100dB SNR. Conexant supports both Applestyle and Nokia-style headsets, as well in-line command
sensing for headset button controls.
One single-ended line output can be used to drive power
speakers or external devices. One differential
microphone/line-in port is available, which is re-taskable
to be single-ended. A programmable microphone boost
and bias is provided. Local analog loopback with EQ/DRC
from line or microphone inputs to the outputs can be
configured. A Digital Microphone Interface (DMIC) allows
interfacing to two digital microphones, and includes a
hardware DC-level filter that eliminates problems caused
by digital microphones with DC offset. Programmable
microphone clock outputs of 3.072MHz and 1.536MHz
are available. Hardware Automatic Gain Control (AGC) is
available for all microphone paths to normalize the
capture levels in real-time.
07/31/14
•
Depending on the master clock, the CX20745 has a
stereo 8-bit/16-bit/24-bit:
– Digital-to-Analog Converter (DAC) that supports
sample rates capable of 8kHz,
8.018kHz,11.025kHz, 12kHz, 16kHz, 16.0364kHz,
22.05kHz, 24kHz, 32kHz, 44.1kHz, 48kHz,
88.2kHz, and 96kHz
■ 98dB dynamic range, 101dB SNR
■ –85dB Total Harmonic Distortion (THD)
– Analog-to-Digital Converter (ADC) that supports
sample rates capable of 8kHz, 8.018kHz,
11.025kHz, 12kHz, 16kHz, 16.0364kHz, 22.05kHz,
24kHz, 32kHz, 44.1kHz, and 48kHz
Provides independent gain and mute control for both
DAC and ADC
•
Data interface—I2S that can be converted to Pulse
Code Modulation (PCM)
•
•
Control Interface—I2C slave only
Supports master clocks of 24.576MHz and
22.5792MHz
Line-in Loopback mode, where the input signal loops
back to the DAC for playback with the EQ/DRC
PopShield active anti-pop ensures no pops or clicks
All digital interfaces operate at 3.3V
Integrated LDO converts 5V to 3.3V, and 3.3V to 1.8V
Pulse Density Modulated (PDM) digital microphone
interface supports a clock frequency of 3.072MHz and
1.536MHz
Jack sense supports up to four jacks with selectable
de-bounce
•
•
•
•
•
•
Applications
•
•
•
•
•
•
Mobile Internet devices
Tablets
Digital dock stations
Portable Navigation Devices (PNDs)
Portable Media Players (PMPs)
Portable gaming systems
Conexant Confidential • www.conexant.com
008DSR00
CX20745 Data Sheet
Revision History
Revision History
Document/
Revision No.
Release Date Change Description
008DSR00
07/31/14
Template and minor text updates.
F
03/30/12
Minor updates.
E
11/30/11
Updated the "Transmitter and Receiver Configuration” figure to include the
CX20745 part number on the receiver and transmitter blocks.
D
05/19/11
Updated:
•
•
"Power Consumption" table.
"Package Dimensions" to "Package Dimensions and Thermal Specifications."
Added:
•
"Thermal Specifications" table.
Complete document update.
Added "Appendix A."
C
05/03/11
•
•
B
01/26/11
Complete document update.
A
10/14/10
Initial release.
Conexant Confidential
07/31/14
008DSR00
ii
CX20745 Data Sheet
Table of Contents
Table of Contents
General Description.......................................................................................................................................................i
Features..........................................................................................................................................................................i
Applications ...................................................................................................................................................................i
Revision History ...........................................................................................................................................................ii
Introduction...................................................................................................................................................................1
Overview............................................................................................................................................................................... 1
Features................................................................................................................................................................................ 2
Packaging............................................................................................................................................................................. 2
Applications ..................................................................................................................................................................3
Block Diagram...................................................................................................................................................................... 3
Hardware Interface .......................................................................................................................................................4
Pin Information .................................................................................................................................................................... 5
Pin Configuration ........................................................................................................................................................ 5
Pin Assignments ......................................................................................................................................................... 6
Pin Signal Definitions.................................................................................................................................................. 7
Electrical Characteristics.............................................................................................................................................9
Package Dimensions and Thermal Specifications ..................................................................................................12
Device Description .....................................................................................................................................................13
Analog Audio Input Paths................................................................................................................................................. 13
Analog-to-Digital Converter (ADC) ........................................................................................................................... 13
Microphone/Line Input .............................................................................................................................................. 13
Microphone Bias (Micbias) Generator ...................................................................................................................... 13
Jack Sense ............................................................................................................................................................... 14
Analog Audio Output Paths.............................................................................................................................................. 14
Digital-to-Analog Converter (DAC) ........................................................................................................................... 14
Line-Out .................................................................................................................................................................... 14
Class-D/Pulse-Width Modulation (PWM).................................................................................................................. 14
Capless Headphone Driver....................................................................................................................................... 15
Digital Audio....................................................................................................................................................................... 15
Pulse Code Modulation (PCM)/Integrated Interchip Sound (I2S) Interface .............................................................. 15
I2S............................................................................................................................................................................. 16
PCM.......................................................................................................................................................................... 20
Conexant Confidential
07/31/14
008DSR00
iii
CX20745 Data Sheet
Table of Contents
Control Interface ....................................................................................................................................................... 21
Digital Signal Processing (DSP)....................................................................................................................................... 23
Equalizer (EQ)/Dynamic Range Compressor (DRC)................................................................................................ 24
Digital Microphone Interface (DMIC) ........................................................................................................................ 25
Automatic Gain Control (AGC) Record Path ............................................................................................................ 26
General Purpose Input/Output (GPIO) Functions..................................................................................................... 28
GPIO 3...................................................................................................................................................................... 32
GPIO 4...................................................................................................................................................................... 32
Clocking.............................................................................................................................................................................. 32
Clock Inputs .............................................................................................................................................................. 32
Registers .....................................................................................................................................................................33
Register Summary ............................................................................................................................................................. 33
Register Details.................................................................................................................................................................. 38
Coder-Decoder (CODEC) Control Registers ............................................................................................................ 38
Data I/F Registers..................................................................................................................................................... 46
AGC Registers.......................................................................................................................................................... 49
Test Registers........................................................................................................................................................... 59
Read Only Registers................................................................................................................................................. 62
GPIO Registers......................................................................................................................................................... 64
Ordering Information..................................................................................................................................................66
Conexant Confidential
07/31/14
008DSR00
iv
CX20745 Data Sheet
List of Figures
List of Figures
Figure 1: CX20745 Block Diagram ................................................................................................................................................... 3
Figure 2: Hardware Interface Signals ............................................................................................................................................... 4
Figure 3: CX20745 48-QFN Pin Configuration ................................................................................................................................. 5
Figure 4: Package Diagram ............................................................................................................................................................ 12
Figure 5: Transmitter and Receiver Configuration .......................................................................................................................... 16
Figure 6: I2S Timing........................................................................................................................................................................ 17
Figure 7: One-Clock Data Shift ....................................................................................................................................................... 17
Figure 8: Left-Justified Timing......................................................................................................................................................... 18
Figure 9: Right-Justified Timing ...................................................................................................................................................... 18
Figure 10: I2S Transmitter Timing................................................................................................................................................... 19
Figure 11: Short Frame Sync (Shown with 16-Bit Sample) ............................................................................................................ 20
Figure 12: Long Frame Sync (Shown with 8-Bit Companded Sample) .......................................................................................... 20
Figure 13: Transferring Data on I2C................................................................................................................................................ 21
Figure 14: Data Transfer Format .................................................................................................................................................... 22
Figure 15: Definition of Timing for F/S-Mode Devices on the I2C Bus............................................................................................ 23
Figure 16: DAC Digital Section ....................................................................................................................................................... 23
Figure 17: DRC Threshold .............................................................................................................................................................. 24
Figure 18: DMIC.............................................................................................................................................................................. 25
Figure 19: DMIC Timing.................................................................................................................................................................. 26
Figure 20: AGC Record Path .......................................................................................................................................................... 26
Figure 21: Rotary Encoder.............................................................................................................................................................. 28
Figure 22: Rotary Encoder Block Diagram ..................................................................................................................................... 28
Figure 23: Chattering Prevention Circuit Block Diagram ................................................................................................................ 29
Figure 24: Up/Down Detection Circuit............................................................................................................................................. 31
Conexant Confidential
07/31/14
008DSR00
V
CX20745 Data Sheet
List of Tables
List of Tables
Table 1: Pin Assignments ................................................................................................................................................................. 6
Table 2: Pin Signal Definitions.......................................................................................................................................................... 7
Table 3: General ............................................................................................................................................................................... 9
Table 4: Mic/Line Input...................................................................................................................................................................... 9
Table 5: Class-D/Speaker Output ..................................................................................................................................................... 9
Table 6: Line Output ......................................................................................................................................................................... 9
Table 7: Headphone Output............................................................................................................................................................ 10
Table 8: Charge Pump.................................................................................................................................................................... 10
Table 9: Micbias.............................................................................................................................................................................. 10
Table 10: Jack Sensing................................................................................................................................................................... 10
Table 11: Voltage Regulator ........................................................................................................................................................... 11
Table 12: Power Consumption........................................................................................................................................................ 11
Table 13: Thermal Specifications.................................................................................................................................................... 13
Table 14: Jack Sense Impedance Values....................................................................................................................................... 14
Table 15: DAC ................................................................................................................................................................................ 15
Table 16: ADC ................................................................................................................................................................................ 16
Table 17: Master Transmitter with a Data Rate of 2.5MHz (±10%) (All Values in ns).................................................................... 19
Table 18: Slave Receiver with a Data Rate of 2.5MHz (±10%) (All Values in ns).......................................................................... 19
Table 19: Slave Addressing Format for I2C .................................................................................................................................... 22
Table 20: I2C Conditions ................................................................................................................................................................ 23
Table 21: Pins Used........................................................................................................................................................................ 25
Table 22: EC16B Standard Data .................................................................................................................................................... 29
Table 23: Clock Inputs .................................................................................................................................................................... 32
Table 24: Register Summary .......................................................................................................................................................... 33
Table 25: Equalizer Crossover Enable Bypass (0x00) ................................................................................................................... 38
Table 26: Equalizer Coefficient B0 High (0x01) .............................................................................................................................. 38
Table 27: Equalizer Coefficient B0 Low (0x02)............................................................................................................................... 38
Table 28: Equalizer Coefficient B1 High (0x03) .............................................................................................................................. 38
Table 29: Equalizer Coefficient B1 Low (0x04)............................................................................................................................... 39
Table 30: Equalizer Coefficient B2 High (0x05) .............................................................................................................................. 39
Table 31: Equalizer Coefficient B2 Low (0x06)............................................................................................................................... 39
Table 32: Equalizer Coefficient A0 High (0x07) .............................................................................................................................. 39
Table 33: Equalizer Coefficient A0 Low (0x08)............................................................................................................................... 39
Conexant Confidential
07/31/14
008DSR00
VI
CX20745 Data Sheet
List of Tables
Table 34: Equalizer Coefficient A1 High (0x09) .............................................................................................................................. 39
Table 35: Equalizer Coefficient A1 Low (0x0A) .............................................................................................................................. 39
Table 36: Gain (0x0B)..................................................................................................................................................................... 39
Table 37: Coeff Load Control (0x0C) .............................................................................................................................................. 40
Table 38: DRC_Gain High (0x0D) .................................................................................................................................................. 40
Table 39: DRC_Gain Low (0x0E) ................................................................................................................................................... 40
Table 40: DAC 1:2 Sample Size/Rate (0x0F) ................................................................................................................................. 41
Table 41: DAC 1 (Left Channel) Volume/Mute Control (0x10)........................................................................................................ 41
Table 42: DAC 2 (Right Channel) Volume/Mute Control (0x11) ..................................................................................................... 42
Table 43: Digital Microphone Control (0x12) .................................................................................................................................. 42
Table 44: ADC Sample Rate/Enable Register (0x13)..................................................................................................................... 43
Table 45: ADC Left Channel Volume/Mute Control (0x14) ............................................................................................................. 43
Table 46: ADC Right Channel Volume/Mute Control (0x15)........................................................................................................... 44
Table 47: HP Control Register (0x16)............................................................................................................................................. 44
Table 48: Line-Out Control Register (0x17) .................................................................................................................................... 45
Table 49: SPKR Control Registers (0x18) ...................................................................................................................................... 45
Table 50: ADC Analog Left Channel Control Register (0x19)......................................................................................................... 45
Table 51: ADC Analog Right Channels Control Register (0x1A) .................................................................................................... 46
Table 52: Micbias Control Register (0x1B) ..................................................................................................................................... 46
Table 53: I2S Transmitter Control-1 (0x1C).................................................................................................................................... 46
Table 54: I2S Transmitter Control-2 (0x1D).................................................................................................................................... 46
Table 55: I2S Receiver Control-1 (0x1E) ........................................................................................................................................ 47
Table 56: I2S Receiver Control-2 (0x1F) ........................................................................................................................................ 47
Table 57: I2S/PCM Control-1 (0x20)............................................................................................................................................... 47
Table 58: I2S/PCM Control-2 (0x21)............................................................................................................................................... 47
Table 59: PCM Transmitter Control-1 (0x22).................................................................................................................................. 48
Table 60: PCM Transmitter Control-2 (0x23).................................................................................................................................. 48
Table 61: PCM Transmitter Control-3 (0x24).................................................................................................................................. 48
Table 62: PCM Receiver Control-1 (0x25)...................................................................................................................................... 48
Table 63: PCM Receiver Control-2 (0x26)...................................................................................................................................... 48
Table 64: PCM Receiver Control-3 (0x27)...................................................................................................................................... 49
Table 65: AD_DC_REJECT_POLE (0x28) ..................................................................................................................................... 49
Table 66: AD_BETA_VOICE SHFT (0x29)..................................................................................................................................... 49
Table 67: AD_BETA_NOISE_SHFT (0x2A) ................................................................................................................................... 49
Table 68: AD_TEST_GAIN (0x2B) ................................................................................................................................................. 49
Conexant Confidential
07/31/14
008DSR00
VII
CX20745 Data Sheet
List of Tables
Table 69: AD_RELEASE_DELAY MSB (0x2C) .............................................................................................................................. 50
Table 70: AD_RELEASE_DELAY LSB (0x2D) ............................................................................................................................... 50
Table 71: AD_POWERIN_INITVAL MSB (0x2E)............................................................................................................................ 50
Table 72: AD_POWERIN_INITVAL LSB (0x2F) ............................................................................................................................. 50
Table 73: AD_MIN_SNR MSB (0x30)............................................................................................................................................. 50
Table 74: AD_MIN_SNR LSB (0x31).............................................................................................................................................. 50
Table 75: AGC_VOLUME_RAMP_STEP (0x32) ............................................................................................................................ 50
Table 76: AD_POWERNOISE_INITVAL MSB (0x33)..................................................................................................................... 51
Table 77: AD_POWERNOISE_INITVAL LSB (0x34)...................................................................................................................... 51
Table 78: AD_MIN_THRESH MSB (0x35)...................................................................................................................................... 51
Table 79: AD_MIN_THRESH LSB (0x36)....................................................................................................................................... 51
Table 80: AD_ON2OFF_DELAY_BLOCKS (0x37)......................................................................................................................... 51
Table 81: AGC_UPDATE_BKS (0x38) ........................................................................................................................................... 51
Table 82: AGC_ENERGY_THRESH_LO MSB (0x39) ................................................................................................................... 51
Table 83: AGC_ENERGY_THRESH_HI MSB (0x3A) .................................................................................................................... 52
Table 84: AGC_STABILITY_BLOCKS (0x3B) ................................................................................................................................ 52
Table 85: AGC_STEP_UP (0x3C) .................................................................................................................................................. 52
Table 86: AGC_STEP_DOW MSB (0x3D) ..................................................................................................................................... 52
Table 87: AGC_STAB_CNT_POS_INC (0x3E) .............................................................................................................................. 52
Table 88: AGC_STAB_CNT_NEG_INC (0x3F) .............................................................................................................................. 52
Table 89: DRC_RELEASE_DELAY MSB (0x40)............................................................................................................................ 52
Table 90: DRC_GAIN_STEP_SLOW (0x41) .................................................................................................................................. 53
Table 91: DRC_GAIN_STEP_FAST (0x42).................................................................................................................................... 53
Table 92: DRC_MAX_LIN_OUT (0x43) .......................................................................................................................................... 53
Table 93: DRC_GAIN_SHIFT (0x44).............................................................................................................................................. 53
Table 94: DRC_MAXABS_INITVAL (0x45) .................................................................................................................................... 53
Table 95: AGC_GAIN_INITVAL (0x46)........................................................................................................................................... 54
Table 96: DRC_OUTPUT_LIMIT (0x47) ......................................................................................................................................... 54
Table 97: AGC_CLIPPING_THRESH (0x48) ................................................................................................................................. 54
Table 98: DAC_HP_CNTRL (0x59) ................................................................................................................................................ 54
Table 99: Line In Loop (I2S Input) Gain Control (0x5A).................................................................................................................. 55
Table 100: Volume GPIO Control (0x5B)........................................................................................................................................ 55
Table 101: Volume Control (0x5C) ................................................................................................................................................. 55
Table 102: Interrupt Enable (0x5D)................................................................................................................................................. 56
Table 103: Interrupt Status (0x5E).................................................................................................................................................. 56
Conexant Confidential
07/31/14
008DSR00
VIII
CX20745 Data Sheet
List of Tables
Table 104: SPKR_DRC_ATTACK_UPDATE_STEP (0x64) ........................................................................................................... 56
Table 105: SPKR_DRC_RELEASE_UPDATE_STEP (0x65)......................................................................................................... 56
Table 106: SPKR_DRC_RELEASE_DELAY (0x66)....................................................................................................................... 56
Table 107: SPKR_DRC_TRANSIENT_UPDATE_STEP (0x67)..................................................................................................... 57
Table 108: SPKR_DRC_TRANSIENT_RELEASE_DELAY (0x68) ................................................................................................ 57
Table 109: SPKR_DRC_BOOST_DB MSB (0x69)......................................................................................................................... 57
Table 110: SPKR_DRC_BOOST_DB LSB (0x6A) ......................................................................................................................... 57
Table 111: SPKR_DRC_MAX_LIN_OUT_DBFS MSB (0x6B) ....................................................................................................... 57
Table 112: SPKR_DRC_MAX_LIN_OUT_DBFS LSB (0x6C) ........................................................................................................ 57
Table 113: SPKR_DRC_OUT_LIMIT_DBFS MSB (0x6D) ............................................................................................................. 57
Table 114: SPKR_DRC_OUT_LIMIT_DBFS LSB (0x6E)............................................................................................................... 57
Table 115: SPKR_DRC_IN_LIMIT_DB MSB (0x6F) ...................................................................................................................... 58
Table 116: SPKR_DRC_IN_LIMIT_DB LSB (0x70)........................................................................................................................ 58
Table 117: SPKR_DRC_BALANCE_RAMP_STEP MSB (0x71).................................................................................................... 58
Table 118: SPKR_DRC_COMP_RATIO LSB (0x72)...................................................................................................................... 58
Table 119: SPKR_DRC_GAIN_SHIFT (0x73) ................................................................................................................................ 58
Table 120: SPKR_DRC_MAXABS_INITVAL (0x74)....................................................................................................................... 58
Table 121: SPKR_DRC_VOLUME_RAMP_STEP (0x75) .............................................................................................................. 58
Table 122: SPKR_DRC_MAX_RAMP_STEP_SHIFT (0x76) ......................................................................................................... 58
Table 123: SPKR_DRC_RELEASE_RATE_TH (0x77) .................................................................................................................. 59
Table 124: CODEC Test 0 (0x88)................................................................................................................................................... 59
Table 125: CODEC Test 21 (0x9D) ................................................................................................................................................ 59
Table 126: CODEC Test 22 (0x9E) ................................................................................................................................................ 59
Table 127: CODEC Test 23 (0x9F)................................................................................................................................................. 60
Table 128: Analog Test 4 (0xA8) .................................................................................................................................................... 60
Table 129: Analog Test 5 (0xA9) .................................................................................................................................................... 61
Table 130: Analog Test 6 (0xAA).................................................................................................................................................... 61
Table 131: Analog Test 8 (0xAC).................................................................................................................................................... 61
Table 132: Analog Test 13 (0xB1) .................................................................................................................................................. 62
Table 133: Analog Test 14 (0xB2) .................................................................................................................................................. 62
Table 134: Monitor ADC LSB (0xE1) .............................................................................................................................................. 62
Table 135: Monitor ADC MSB (0xE2) ............................................................................................................................................. 62
Table 136: Jack Sense Status and Bond Option (0xE3)................................................................................................................. 62
Table 137: Class-D Protection Status (0xE4) ................................................................................................................................. 63
Table 138: Class-D Calibration Observe (0xE5)............................................................................................................................. 63
Conexant Confidential
07/31/14
008DSR00
IX
CX20745 Data Sheet
List of Tables
Table 139: HP A Offset Calibration Observe (0xE6)....................................................................................................................... 63
Table 140: HP B Offset Calibration Observe (0xE7)....................................................................................................................... 63
Table 141: Memory BIST Status (0xE8) ......................................................................................................................................... 63
Table 142: AGC Gain LSB Read Register (0xE9) .......................................................................................................................... 63
Table 143: AGC Gain MSB Read Register (0xEA)......................................................................................................................... 64
Table 144: SPKR DRC Gain LSB Read Register (0xEB) ............................................................................................................... 64
Table 145: SPKR DRC Gain MSB Read Register (0xEC).............................................................................................................. 64
Table 146: Micbias Detect Read Register (0xED) .......................................................................................................................... 64
Table 147: GPIO In Registers (0xF1) ............................................................................................................................................. 64
Table 148: GPIO Out Registers (0xF2)........................................................................................................................................... 65
Table 149: GPIO Direction Registers (0xF3) .................................................................................................................................. 65
Table 150: GPIO Control Registers (0xF4)..................................................................................................................................... 65
Table 151: I2S DATA Control (0xF5) .............................................................................................................................................. 65
Table 152: DMIC Drive Control (0xF6) ........................................................................................................................................... 65
Table 153: Device ID LSB (0xFD)................................................................................................................................................... 65
Table 154: Device ID MSB (0xFE).................................................................................................................................................. 66
Table 155: Bond Option Read (0xFF)............................................................................................................................................. 66
Table 156: Ordering Information..................................................................................................................................................... 66
Conexant Confidential
07/31/14
008DSR00
X
CX20745 Data Sheet
Introduction
Introduction
Overview
The CX20745 is an I2S audio CODEC, with integrated stereo class-D speaker amplifiers and capless
headphones with performance that exceeds 100dB SNR. Innovative DSP maximizes speaker loudness
without distortion, performs loudness compensation, and normalizes microphone pick-up levels. Combined
with Conexant’s software and design support services, the CX20745 is an ideal turnkey solution for
tablets, ultrabooks, portable media players, SMART phones, and digital docking stations.
The integrated filterless class-D stereo amplifier with spread spectrum EMI dispersion technology is
capable of driving up to 2W RMS per channel into 4 speakers. Built-in, fully configurable hardware EQ
and DRC improve frequency response, maximize the output volume, and get best audio performance from
integrated speakers independent of the driver and OS.
A stereo pair of capless headphone drivers includes integrated short circuit protection and auto-recovery.
These high performance headphone drivers save cost by eliminating external headphone amplifiers and
DC blocking capacitors. The capless architecture outputs a full-range frequency response that exceeds
100dB SNR. Conexant supports both Apple-style and Nokia-style headsets, as well in-line command
sensing for headset button controls.
One single-ended line output can be used to drive power speakers or external devices. One differential
microphone/line-in port is available, which is re-taskable to be single-ended. A programmable microphone
boost and bias is provided. Local analog loopback with EQ/DRC from line or microphone inputs to the
outputs can be configured. A DMIC allows interfacing to two digital microphones, and includes a hardware
DC-level filter that eliminates problems caused by digital microphones with DC offset. Programmable
microphone clock outputs of 3.072MHz and 1.536MHz are available. Hardware AGC is available for all
microphone paths to normalize the capture levels in real-time.
Two integrated Low Dropout Regulators (LDOs) generate the internal clean power rails for analog and
digital. All output ports feature PopShield circuitry that eliminates pops and clicks. Jack sensing is available
that can detect up to four jacks with programmable switch de-bounce.
The digital Input/Output (I/O), Inter-Integrated Circuit (I2C), and I2S interfaces support a wide range of
topologies for connections to application processors and docking stations, and run at 3.3V. The hardware
digital volume control supports Up and Down buttons, as well as an “infinity” volume control knob
commonly found in high-end Audio and Video (AV) equipment. Host processor interrupts can be generated
based on various events such as class-D errors, jack sense activity, and hardware volume control changes
to avoid driver and system polling overheads and ensure immediate event detection.
The CODEC drivers for all major OSs are available.
•
•
•
•
•
In-house developed super wideband Voice Processing Algorithms (VPAs) enhance the clarity of
Voice-over-Internet Protocol (VoIP) calls and improve the accuracy of voice commands and dictation
Far Field Pickup enables long-range speakerphone applications for chat and multi-participant
conference calls
Multi-band dynamic EQ further improves the sound quality of low-cost speakers and prevents speaker
rattle and distortion
Phantom bass creates virtual bass content on mainstream speakers
3D headphone recreates a surround, speaker-like environment in headphones so users can enjoy a
richer and fuller music listening experience
Conexant Confidential
07/31/14
008DSR00
1
CX20745 Data Sheet
Features
Features
•
•
Depending on the master clock, the CX20745 has a stereo 8-bit/16-bit/24-bit:
– DAC that supports sample rates capable of 8kHz, 8.018kHz,11.025kHz, 12kHz, 16kHz,
16.0364kHz, 22.05kHz, 24kHz, 32kHz, 44.1kHz, 48kHz, 88.2kHz, and 96kHz
■ 98dB dynamic range, 101dB SNR
■ –85dB THD
– ADC that supports sample rates capable of 8kHz, 8.018kHz, 11.025kHz, 12kHz, 16kHz,
16.0364kHz, 22.05kHz, 24kHz, 32kHz, 44.1kHz, and 48kHz
Provides independent gain and mute control for both DAC and ADC
•
Data interface—I2S that can be converted to PCM
•
Control Interface—I2C slave only
•
•
Supports master clocks of 24.576MHz and 22.5792MHz
Audio ports:
– Stereo analog input port supports up to two single-ended mono microphones, one differential
mono microphone, one single-ended stereo line input, or one differential mono line input.
– Open Mobile Terminal Platform (OMTP) headset jack is compliant with integrated in-line command
sensing. Microphone Bias (micbias) sensing capability for external headset control. Supports autosense and switching between the MIC and GND pins.
– Stereo class-D amplifier
– Stereo capless headphone port
– Single-ended analog line output (stereo)
– Digital microphone input (stereo)
Class-D amplifier with the following modes of operation:
– Up to 2W per channel into 4, with 5V supply
– Up to 1W per channel into 4, with 3.3V supply
– Spread spectrum for EMI protection on the class-D amplifier
Integrated hardware DSP features a:
– Five-band EQ
– DRC that provides a compressor and limiter
– Microphone AGC
Line-in Loopback mode, where the input signal loops back to the DAC for playback with the EQ/DRC
PopShield active anti-pop ensures no pops or clicks
All digital interfaces operate at 3.3V
Integrated LDO converts 5V to 3.3V, and 3.3V to 1.8V
PDM digital microphone interface supports a clock frequency of 3.072MHz and 1.536MHz
Jack sense supports up to four jacks with selectable de-bounce
Four General Purpose Input/Outputs (GPIOs)—Multi-function pins support GPIO, hardware volume
controls, and system interrupt generation
Power management
•
•
•
•
•
•
•
•
•
•
Packaging
•
•
CX20745-11Z is packaged in a 48-pin QFN
Operating Range: –40°C to 85°C
Conexant Confidential
07/31/14
008DSR00
2
CX20745 Data Sheet
Applications
Applications
•
•
•
•
•
•
Mobile Internet devices
Tablets
Digital dock stations
PNDs
PMPs
Portable gaming systems
Block Diagram
The following figure shows the CX20745 block diagram.
SENSE_A
Jack
Sense
Capless HP Out 32Ω
Micbias
Bias
Generator
Capless HP Out 32Ω
2W Class-D 4Ω
Line/Mic In
M
ADC
AGC
Σ
M
+
-
Five
Band
EQ
DRC
Five
Band
EQ
DRC
PWM Out
DAC
Fault
2W Class-D 4Ω
Line/Mic In
M
ADC
Σ
M
AGC
DAC
10K Line
M
3.3V_FILT
3.3V
LDO
5.0V_IN
3.3V_IN
TX_WS/SYNC
TX_DAT
1.8V_FILT
1.8V
LDO
PCM/I2S
BIT_CLK
PCM/I2S
RX_WS/SYNC
I2C Slave
RX_DAT
Clock
Circuitry
SCL
Master
Clock
10K Line
BIT_CLK
Mic Clock
M
Digital
Mic
SDA
Mic Data
PWM Out
Figure 1: CX20745 Block Diagram
Conexant Confidential
07/31/14
008DSR00
3
CX20745 Data Sheet
Hardware Interface
Hardware Interface
The following figure provides the hardware interface signals.
Analog Power
Digital Power
21/29
30
33
3/45
4
44
14
16
C lass-D Power
19
39
13
37
Charge Pump Flying Cap
GPIOs
Reset
38
36
AVDD_3.3
AVDD_5V
AVDD_HP
VDD
VDDO2
DIG_MIC_DATA
DIG_MIC_CLK
VDDO1
LEFT+
LEFTRIGHTRIGHT+
DVDD_3.3_CD
LEFT PWR
RIGHT PWR
DVDD_3.3_CP
CLASSD_REF
CX20745
48-Pin QFN
FLY_N
FLY_P
LINE_IN_R
LINE_IN_L
GPIO2
GPIO3
12
RSTN
1
2
5
6
7
8
9
10
11
47
32
34
HP_L
35
GPIO4
Class-D Amp
27
LINE_OUT_L
SENSE
Digital Mic
15
17
18
20
LINE_OUT_R
HP_R
GPIO1
I2S/I2C Signals
46
28
31
AVEE
40
41
42
43
49
Pin 49 r efer s to the
exposed ground paddle
MCLK
SCL
SDA
DSCLK
DSDATA
DLRCLK
ASCLK
ASDATA
ALRCK
24
IREF
VREF_1p65
22
23
MICBIAS
26
Analog Signals
J ac k Sens e
Reference Voltage
EP/GND
Microphone Bias
Figure 2: Hardware Interface Signals
Conexant Confidential
07/31/14
008DSR00
4
CX20745 Data Sheet
Pin Information
Pin Information
Pin Configuration
T E ST
D IG _M IC _C LK
D IG _M IC _D AT A
V DD
V DD O 1
G PIO 4
G PIO 3
G PIO 2
G P IO 1
D VD D _3 .3_ C P
F L Y_P
F L Y_ N
45
44
43
42
41
40
39
38
37
1
2
36
AVE E
35
34
33
32
31
HP _L
HP _R
AVD D _H P
LIN E_ O U T _R
LIN E_ O U T _L
30
29
28
AVD D _5 V
A VD D _3 .3
LINE_IN_L
11
27
26
12
25
LINE_IN_R
M IC BIAS
NC
24
C X2 0 7 4 5
SEN S E
10
V R EF _1 P65
AS DA T A
AL RC L K
RSTN
18
19
20
21
22
23
6
7
8
9
16
17
D SC L K
DS DA T A
D L RC L K
ASC L K
L EF T PW R
LE FT R IG HT R IG H T PW R
R IG HT +
AV DD _ 3.3
IR EF
3
4
5
13
14
15
SCL
VD D
V D DO 2
SD A
CLASSD_REF
D VD D _3. 3_ CD
LE F T+
MC L K
48
47
46
The following figure shows the CX20745 pin configuration.
Figure 3: CX20745 48-QFN Pin Configuration
Note: Pin 49 (paddle) is ground.
Conexant Confidential
07/31/14
008DSR00
5
CX20745 Data Sheet
Pin Information
Pin Assignments
The following table lists the CX20745 pin assignments.
Table 1: Pin Assignments
Pad Number
Signal Name
Pad Number
Signal Name
1
MCLK
26
MICBIAS
2
SCL
27
LINE_IN_R
3
VDD
28
LINE_IN_L
4
VDDO2
29
AVDD_3.3
5
SDA
30
AVDD_5V
6
DSCLK
31
LINE_OUT_L
7
DSDATA
32
LINE_OUT_R
8
DLRCK
33
AVDD_HP
9
ASCLK
34
HP_R
10
ASDATA
35
HP_L
11
ALRCK
36
AVEE
12
RSTN
37
FLY_N
13
CLASSD_REF
38
FLY_P
14
DVDD_3.3_CD
39
DVDD_3.3_CP
15
LEFT+
40
GPIO1
16
LEFTPWR
41
GPIO2
17
LEFT-
42
GPIO3
18
RIGHT-
43
GPIO4
19
RIGHTPWR
44
VDDO1
20
RIGHT+
45
VDD
21
AVDD_3.3
46
DIG_MIC_DATA
22
IREF
47
DIG_MIC_CLK
23
VREF_1p65
48
TEST
24
SENSE
49
EP/PADDLE
25
NC
Conexant Confidential
07/31/14
008DSR00
6
CX20745 Data Sheet
Pin Information
Pin Signal Definitions
Table 2 provides the CX20745 pin description. The following lists the acronyms used in this table:
•
•
•
•
AI = Analog In
AO = Analog Out
DI = Digital In
DIO = Digital Input/Output
•
•
•
•
DO = Digital Out
PD = Pull-Down
PU = Pull-Up
PWR = Power
Table 2: Pin Signal Definitions
Pin
Number
I/O Type
Signal Name/Description
VDD
3/45
PWR
Output Voltage from LDO. 1.8V—Connect to an external
decoupling capacitor.
VDDO2
4
PWR
Digital Supply Voltage. 3.3V (+5%).
DVDD_3.3_CD
14
PWR
Class-D 3.3V Supply. 3.3V (+5%).
LEFTPWR
16
PWR
Class-D Left Supply Voltage. Connect to 3.3V to 5V (+5%).
RIGHTPWR
19
PWR
Class-D Right Supply Voltage. Connect to 3.3V to 5V (+5%).
AVDD_3.3
21/29
PWR
3.3V LDO Output (can be used as an input if by-passing the
LDO). 3.3V (5%).
AVDD_5V
30
PWR
5V LDO Input Supply Voltage. Connect to +5V (+5%). For
3.3V-only operation, the LDO may be bypassed by connecting
AVDD_5V to AVDD_3.3 (pins 21/29) and to the 3.3V (+ 5%)
supply.
AVDD_HP
33
PWR
Headphone 3.3V Supply (+ 5%).
AVEE
36
PWR
Internally Generated Analog Negative Supply. Connect to an
external decoupling capacitor.
FLY_N
37
PWR
Charge Pump Fly Capacitor. Connect to FLY_P through a 1μF
capacitor.
FLY_P
38
PWR
Charge Pump Fly Capacitor. Connect to FLY_N through a 1μF
capacitor.
DVDD_3.3_CP
39
PWR
Headphone Negative Charge Pump. 3.3V (+5%).
VDDO1
44
PWR
Digital Supply Voltage. 3.3V (+5%).
EP/GROUND
49
PWR
Ground (Paddle).
Label
Power
Digital Audio and Interface
MCLK
1
Digital In
24.576MHz/22.5792MHz Input Clock. MCLK must be a
derivative of the I2S bit clocks for proper operation.
SCL
2
Digital Out
I2C Clock.
SDA
5
Digital In
I2C Data-in from the Host.
DSCLK
6
Digital In
I2S Bit Clock for the Receiver (Rx).
DSDATA
7
Digital In
I2S Data for Rx.
DLRCK
8
Digital In
I2S Word Clock for Rx.
ASCLK
9
Digital In
I2S Bit Clock for the Transceiver (Tx).
ASDATA
10
Digital In
I2S Data for Tx.
Conexant Confidential
07/31/14
008DSR00
7
CX20745 Data Sheet
Pin Information
Table 2: Pin Signal Definitions (Continued)
Label
Pin
Number
I/O Type
Signal Name/Description
ALRCK
11
Digital In
I2S Word Clock for Tx.
DIG_MIC_DATA
46
Digital In
Digital Microphone Data.
DIG_MIC_CLK
47
Digital Out
Digital Microphone Clock.
Analog Audio and Signals
LEFT+
15
Analog Out Class-D Left (+) Output.
LEFT-
17
Analog Out Class-D Left (–) Output.
RIGHT-
18
Analog Out Class-D Right (–) Output.
RIGHT+
20
Analog Out Class-D Right (+) Output.
SENSE
24
Analog In
Jack Sense Input.
LINE_IN_R
27
Analog In
Mic/Line-in Right/Line-in Mono (-).
LINE_IN_L
28
Analog In
Mic/Line-in Left/Line-in Mono (+).
LINE_OUT_L
31
Analog Out Line-out Left.
LINE_OUT_R
32
Analog Out Line-out Right.
HP_R
34
Analog Out Headphone Right Output.
HP_L
35
Analog Out Headphone Left Output.
CLASSD_REF
13
REF
Class-D Reference. Connect through a 0.1μF capacitor to the
LEFTPWR/RIGHTPWR supply.
IREF
22
REF
Current Reference. Connect to the analog ground through a
54.9k (1%) resistor.
VREF_1p65
23
REF
Internal Analog Reference (Filter Pin).
MICBIAS
26
REF
Micbias Output.
RSTN
12
Digital In
Active-low CODEC Reset.
GPIO1
40
Digital I/O
GPIO1.
GPIO2
41
Digital I/O
GPIO2.
GPIO3
42
Digital I/O
GPIO3.
GPIO4
43
Digital I/O
GPIO4.
Reference
GPIO/Test/Other
Conexant Confidential
07/31/14
008DSR00
8
CX20745 Data Sheet
Electrical Characteristics
Electrical Characteristics
Table 3: General
Parameter
Minimum
Nominal
Maximum
Unit
Comments
Temperature
-40
27
125
°C
Junction temperature.
Table 4: Mic/Line Input
Parameter
Minimum Nominal Maximum Unit
Comments
Gain
0
-
40
dB
In steps of 10dB.
Full Scale Input Signal
-
1
-
VRMS
AC-coupled.
Dynamic Range1
-
87
-
dBFS
A-weighted, 20kHz to 20kHz.
THD plus Noise (THD+N) at –3dBFS -
–80
-
dBFS
20kHz to 20kHz.
Input Resistance
-
15
kΩ
15kΩ with 0dB gain, otherwise 5kΩ.
5
1 = The dynamic range is the ratio of the full scale signal level to the RMS noise floor in the presence of the signal, expressed in
dBFS. This ratio should be measured by performing a THD+N measurement with a –60dBFS signal.
Table 5: Class-D/Speaker Output
Parameter
Minimum Nominal Maximum Unit
Comments
Power
-
•
-
2W
-
•
Output Load
Dynamic
Range1
THD+N at –3dBFS
5V mode:
– Up to 2 with channel 4Ω when a headphone
is not in use
– Up to 1.5 with channel 4Ω when a
headphone is in use
3V mode: Up to 1 with channel 4Ω
-
4
-
Ω
752
-
85
90
dBFS A-weighted, 20kHz to 20kHz.
-
–65
-
dBFS 20kHz to 20kHz into 4Ω.
1 = The dynamic range is the ratio of the full scale signal level to the RMS noise floor in the presence of the signal, expressed in
dBFS. This ratio should be measured by performing a THD+N measurement with a –60dBFS signal.
2 = Although the CX20745 System-on-a-Chip (SoC) audio CODEC is designed to provide nominal class-D dynamic range
performance of 85 dBFS, testing has found that some production parts have an actual performance value as low at 75dBFS.
Table 6: Line Output
Parameter
Minimum Nominal Maximum Unit
Comments
Full Scale Output Signal -
1
-
VRMS AC-coupled.
Output Load
10
-
-
kΩ
-
98
-
dBFS A-weighted, 20kHz to 20kHz.
THD+N at –3dBFS
-
–85
-
dBFS 20kHz to 20kHz into a 10kΩ load.
Crosstalk
-
–70
-
dB
Dynamic
Range1
-
-
1 = The dynamic range is the ratio of the full scale signal level to the RMS noise floor in the presence of the signal, expressed in
dBFS. This ratio should be measured by performing a THD+N measurement with a –60dBFS signal.
Conexant Confidential
07/31/14
008DSR00
9
CX20745 Data Sheet
Electrical Characteristics
Table 7: Headphone Output
Parameter
Minimum Nominal Maximum Unit
Comments
Full Scale Output Signal
-
1
-
VRMS
-
Output Offset
–8
0
8
mV
Reduces to + 250μV with offset cancellation.
Output Load
16
32
-
Ω
Can drive –3dBFS into 16Ω without clipping.
Dynamic Range1
95
-
-
dBFS A-weighted, 20kHz to 20kHz.
THD+N at –3dBFS
-
-
–85
dBFS
20kHz to 20kHz into a 10kΩ load.
Crosstalk
-
-
–70
dB
-
1 = The dynamic range is the ratio of the full scale signal level to the RMS noise floor in the presence of the signal, expressed in
dBFS. This ratio should be measured by performing a THD+N measurement with a –60dBFS signal.
Table 8: Charge Pump
Parameter
Minimum
Nominal
Maximum
Unit
Comments
Input Voltage
3
3.3
3.6
V
dvddh_cpump.
Output Voltage
–2
-
–2.6
V
avee_cpump, programmable.
Current Load
avee = –2
avee = –2.6
-
-
250
150
mA
mA
-
Clock Frequency
-
500
-
kHz
-
Table 9: Micbias
Parameter
Minimum Nominal Maximum Unit Comments
Output Voltage
-
Pad Voltage when Bias Disabled –3.3
1.65
2.65
V
Programmable to be 50%—60% or 80%
of supply.
-
3.3
V
When disabled, the micbias is high-Z
with an option to ground the micbias
pad.
Table 10: Jack Sensing
Parameter
Minimum Nominal Maximum Unit
Comments
Input Voltage
0
-
3.3
V
Off-chip resistor network should be connected to
the AVDDH chip supply.
Pad Sampling Interval
-
10
-
ms
Sampling on sense is interleaved. The ADC
outputs on the sense are de-bounced over 12
samples.
SAR Clock Rate
-
500
-
kHz
Using a Resistor–Capacitor (RC) oscillator.
Conexant Confidential
07/31/14
008DSR00
10
CX20745 Data Sheet
Electrical Characteristics
Table 11: Voltage Regulator
Parameter
Minimum Nominal Maximum Unit Comments
LDO Supply Voltage 3.5
5
5.5
V
avdd5v.
Output Voltage
3.3
3.55
V
•
•
3.15
avddh
avddh_sc, avddh_port
Table 12: Power Consumption
Voltage Power
(V)
(mW)
State
Description
Standby
DAC/ADC Off, Output
VDDO1, VDDO2
Ports Muted in D3,
External Clock Removed AVDD_3.3, AVDD_5V1
3.3
13.93
3.3
3.34
Silent
VDDO1, VDDO2, AVDD_3.32
3.3
48.84
Full Scale
VDDO1, VDDO2, AVDD_3.32
3.3
50.16
VDDO1, VDDO2
3.3
42.90
AVDD_3.3, AVDD_HP, DVDD_3.3_CP3
3.3
45.54
VDDO1, VDDO2
3.3
44.06
AVDD_3.3, AVDD_HP, DVDD_3.3_CP3
3.3
61.71
VDDO1, VDDO2
3.3
44.06
3.3
211.20
VDDO1, VDDO2, AVDD_3.3, DVDD_3.3_CD1
3.3
78.87
LEFTPWR, RIGHTPWR
3.3
28.71
3.3
78.21
LEFTPWR, RIGHTPWR
3.3
2455.20
VDDO1, VDDO2, AVDD_3.3, DVDD_3.3_CD1
3.3
78.87
LEFTPWR, RIGHTPWR
5
65
VDDO1, VDDO2, AVDD_3.3, DVDD_3.3_CD1
3.3
78.21
LEFTPWR, RIGHTPWR
5
4635
Line Level Stereo
Playback (10kΩ)
Play Silence
Headphone Stereo
Playback (32Ω)
Play 1mW output
Play Full Scale
Supply
AVDD_3.3, AVDD_HP,
Class-D Stereo
Playback (4Ω Speaker,
3.3V Supply, 1W)
Class-D Stereo
Playback (4Ω Speaker,
5V Supply, 2W)
Play Silence
Play Full Scale
Play Silence
Play Full Scale
DVDD_3.3_CP3
VDDO1, VDDO2, AVDD_3.3,
DVDD_3.3_CD1
Stereo Recording
Line Level
VDDO1, VDDO2, AVDD_3.34
3.3
53.10
Full-duplex—Line In
and Headphone
Silence
VDDO1, VDDO2, AVDD_3.3, DVDD_3.3_CP,
AVDD_HP5
3.3
129.69
Line Input to
Silence
Headphone Digital Loop
VDDO1, VDDO2, AVDD_3.3, DVDD_3.3_CP,
AVDD_HP5
3.3
127.05
1 = The DVDD_3.3_CP and AVDD_HP supplies are grounded. The AVDD_5V supply is connected to AVDD_3.3 (LDO bypassed).
2 = The AVDD_HP, DVDD_3.3_CP, DVDD_3.3_CD, LEFTPWR, and RIGHTPWR supplies are all grounded. The AVDD_5V supply
is connected to AVDD_3.3 (LDO bypassed).
3 = The DVDD_3.3_CD, LEFTPWR, RIGHTPWR supplies are all grounded. The AVDD_5V supply is connected to AVDD_3.3 (LDO
bypassed).
4 = The AVDD_HP, DVDD_3.3_CP, DVDD_3.3_CD, LEFTPWR, RIGHTPWR supplies are all grounded. The AVDD_5V supply is
connected to AVDD_3.3 (LDO bypassed).
5 = The LEFTPWR, RIGHTPWR, DVDD_3.3_CD supplies are all grounded. The AVDD_5V supply is connected to AVDD_3.3 (LDO
bypassed).
Conexant Confidential
07/31/14
008DSR00
11
CX20745 Data Sheet
Package Dimensions and Thermal Specifications
Package Dimensions and Thermal Specifications
The following figure provides the CX20745 package diagram.
S
Y
M
B
O
L
A
A1
A2
A3
D
D1
E
E1
Θ
P
Q
R
COMMON
DIMENSIONS
MIN.
NOM.
MAX
0.80
0.00
0.60
0.85
0.01
0.65
0.20 REF.
6.00 BSC
5.75 BSC
6.00 BSC
5.75 BSC
-0.42
0.40
0.17
0.90
0.05
0.70
0
0.24
0.30
0.13
12o
0.60
0.65
0.23
10
8, 11
8, 11
GENERAL: NOMINAL EXPOSED PAD D2/E2 DIMENSION = NOMINAL DIE ATTACH
PAD DIMENSION - 0.20
NOMINAL DIE ATTACH PAD DIMENSION
0.10
NOMINAL EXPOSED PAD D2/E2 DIMENSION
0.10
<DIE ATTACH PAD X - SECTION VIEW>
4.30
4.30
4.40
4.40
4.50
4.50
Figure 4: Package Diagram
Conexant Confidential
07/31/14
008DSR00
12
CX20745 Data Sheet
Device Description
The following table defines the thermal specifications.
Table 13: Thermal Specifications
Parameter
Symbol Minimum Typical Maximum Units Notes
Theta-JA (Junction-to-Ambient JA
Thermal Resistance)
-
31.91
-
o
Psi-JT (Junction-to-Package
JT
Top Thermal Characterization
Parameter)
-
0.09
-
o
C/W Four-layer Printed Circuit Board
(PCB) with a solid ground plane
and thermal vias (still air).
C/W Four-layer PCB with a solid
ground plane and thermal vias
(still air).
Note: Measurements are per the JEDEC EIA/JESD 51 standard. The JA of application boards with
more than four layers stay the same or improve if the PCB construction is similar to the JEDEC EIA/
JESD 51 defined four-layer PCB (2S2P plus vias).
Device Description
Analog Audio Input Paths
Analog-to-Digital Converter (ADC)
One stereo ADC is connected to the mic/line input. Conexant supports sample widths of 8-bit, 16-bit, and
24-bit at sample rates of either:
•
•
8kHz, 12kHz, 24kHz, 32kHz, and 48kHz at the 24.576MHz master clock
8.0182kHz, 11.025kHz, 16.0364kHz, 22.05kHz, or 44.1kHz at the 22.5792MHz master clock
Microphone/Line Input
Two analog input buffers with adjustable gain settings. With the gain set at 0dB, the input buffer can accept
a 1VRMS signal.
Microphone Bias (Micbias) Generator
The bias generator is capable of generating a controllable 2.64V (8% of 3.3V) bias voltage to support an
analog microphone. The bias voltage can be disabled, which puts the bias buffer in a low-power and highimpedance mode. The buffer output pads allow for a full 1VRMS swing below ground without and
impedance change.
Conexant Confidential
07/31/14
008DSR00
13
CX20745 Data Sheet
Analog Audio Output Paths
Jack Sense
Jack sense is provided that can sense up to four jacks using an external resistor divider network.
Grounding a resistor indicates that an audio device is connected to the corresponding port. It is possible to
map the four jack sense bits to any input or output port. The de-bounce time is adjustable with a default of
250ms.
Table 14: Jack Sense Impedance Values
Jack
Impedance
Line-out
5.11kΩ
Line/MIc-R
10kΩ
Line/Mic-L
20kΩ
Headphone
39.2kΩ
Analog Audio Output Paths
Digital-to-Analog Converter (DAC)
One stereo DAC is available with sample widths of 8-bit, 16-bit, and 24-bit at sample rates of either:
•
•
8kHz, 12kHz, 24kHz, 32kHz, 48kHz, and 96kHz at the 24.576MHz master clock
8.0182kHz, 11.025kHz, 16.0364kHz, 22.05kHz, 44.1kHz, or 88.2kHz at the 22.5792MHz master clock
Line-Out
The line output can drive 1VRMS into a 10k load, and meets the DAC path performance specifications.
The line-outs have the following configuration options:
•
•
•
Power on/off
Differential or single-ended operating mode
1VRMS or 2VRMS output level (differential mode)
•
Mute on/off
Class-D/Pulse-Width Modulation (PWM)
The output drivers can be configured for either Pulse-Width Modulation (PWM) or class-D speaker output.
The drivers can either provide differential PWM output signals to drive external class-D amplifiers or can
drive up to 2W RMS into 4 speakers, and meet the specified speaker path performance requirements.
The class-D/PWM outputs have the following configuration options:
•
•
•
•
•
Power on/off
PWM or class-D mode
Spread spectrum clocking and low EMI clocking
Single-channel operation
Over current protection, under voltage protection, and over temperature protection
Conexant Confidential
07/31/14
008DSR00
14
CX20745 Data Sheet
Digital Audio
Capless Headphone Driver
Two output drivers can be configured for either line-out (10k load) or headphone-out (32 load). The
drivers can drive 50mW into a 32 load or 1VRMS into a 10k load, and meet the specified DAC path
performance requirements. The capless headphone outputs have the following configuration options:
•
•
Power on/off
Mute on/off
Digital Audio
Pulse Code Modulation (PCM)/Integrated Interchip Sound (I2S) Interface
The CX20745 CODEC contains a single digital data audio interface either through I2S Tx/Rx or through the
PCM. A six-wire I2S T/Rx can be converted to a six-wire PCM interface through the I2C control. The
following lists the six wires for the interface:
•
•
•
•
•
•
DSCLK
DSATA
DLRCK
ASCLK
ASDATA
ALRCK
The I2S Tx and Rx support different sampling frequencies of either 48K or 44.1K multiples. Both PCM and
I2S only support the slave configuration. Table 15 and Table 16 provide the supporting sampling frequency
with the associated bit clock.
Table 15: DAC
DAC Sample Rate
DAC Bit Clock
Master Clock
8kHz (BCLK/64)
0.512MHz (MCLK/48)
24.576MHz
12kHz (BCLK/64)
0.768MHz (MCLK/32)
24.576MHz
16kHz (BCLK/64)
1.024MHz (MCLK/24)
24.576MHz
24kHz (BCLK/64)
1.536MHz (MCLK/16)
24.576MHz
32kHz (BCLK/64)
2.048MHz (MCLK/12)
24.576MHz
48kHz (BCLK/64)
3.072MHz (MCLK/8)
24.576MHz
96kHz (BCLK/64)
6.144MHz (MCLK/4)
24.576MHz
8.0182kHz (BCLK/64)
0.513MHz (MCLK/44)
22.5792MHz
11.025kHz (BCLK/64)
0.7056MHz (MCLK/32)
22.5792MHz
16.0364kHz (BCLK/64)
1.026MHz (MCLK/22)
22.5792MHz
22.05kHz (BCLK/64)
1.44112MHz (MCLK/16)
22.5792MHz
44.1kHz (BCLK/64)
2.8224MHz (MCLK/8)
22.5792MHz
88.2kHz (BCLK/64)
5.6448MHz (MCLK/4)
22.5792MHz
Conexant Confidential
07/31/14
008DSR00
15
CX20745 Data Sheet
Digital Audio
Table 16: ADC
ADC Sample Rate
ADC Bit Clock
Master Clock
8kHz (BCLK/64)
0.512MHz (MCLK/48)
24.576MHz
12kHz (BCLK/64)
0.768MHz (MCLK/32)
24.576MHz
16kHz (BCLK/64)
1.024MHz (MCLK/24)
24.576MHz
24kHz (BCLK/64)
1.536MHz (MCLK/16)
24.576MHz
32kHz (BCLK/64)
2.048MHz (MCLK/12)
24.576MHz
48kHz (BCLK/64)
3.072MHz (MCLK/8)
24.576MHz
8.0182kHz (BCLK/64)
0.513MHz (MCLK/44)
22.5792MHz
11.025kHz (BCLK/64)
0.7056MHz (MCLK/32)
22.5792MHz
16.036kHz (BCLK/64)
1.026MHz (MCLK/22)
22.5792MHz
22.05kHz (BCLK/64)
1.44112MHz (MCLK/16)
22.5792MHz
44.1kHz (BCLK/64)
2.8224MHz (MCLK/8)
22.5792MHz
I2S
Figure 5 shows the transmitter and receiver configuration in relationship with master and slave
terminology. The CX20745 operates in slave mode only.
Clock SCK
Transmitter
Clock SCK
Word Select WS
Data SD
CX20745
(Receiver)
CX20745
(Transmitter)
Transmitter = Master
Word Select WS
Data SD
Receiver
Receiver = Master
Figure 5: Transmitter and Receiver Configuration
The CX20745 I2S interface supports three different modes of the data transfer operation.
Conexant Confidential
07/31/14
008DSR00
16
CX20745 Data Sheet
Digital Audio
I2S Justified
The I2S timing uses LRCK to define when the data being transmitted is for the left and right channels. The
WS is low for the left channel, and high for the right channel. A WS polarity control bit is provided to allow
either high or low to represent the left channel. The default setting of the polarity control is 0, which means
low WS = left channel. The WS does not need to be symmetrical. A system clock (clk_au) running at a
minimum of 2 x (sample width +1) x sample frequency is used to clock in the data. There is a delay of one
clock bit from the time the LRCK signal changes state to the first data bit on the data line. The data is
written Most Significant Bit (MSB) first, and is valid on the rising edge of the bit clock. When the
programmed sample width is taken, any remaining bits are ignored.
1/fs
L-Channel
1
2
3
R-Channel
N-2 N-1 N
MSB
1
LSB
2
3
N-2 N-1 N
MSB
1
2
LSB
Figure 6: I2S Timing
Important! One case to be careful of in dealing with I2S is when the number of bits in the sample word
matches the number of clocks per frame. Because true I2S requires a one-clock shift of the data, the Least
Significant Bit (LSB) of each word arrives after the WS signal changes state (illustrated in Figure 7). To
handle this correctly, the internal channel indicator should only change state after the bit count is reached
and the state of LRCK does not match the expected value for the current channel.
LRCLK
16 Clks
16 Clks
Left Channel
Right Channel
SCLK
SCLK
MSB
LSB
LSB
MSB
16-bit Mode
15
14
13
12
11
10
9
8
5
4
3
2
1
0
15
14
13
12
11
10
9
8
5
4
3
2
1
Figure 7: One-Clock Data Shift
Conexant Confidential
07/31/14
008DSR00
17
CX20745 Data Sheet
Digital Audio
Left-Justified
Left-justified timing uses the LRCK clock to define when the data being transmitted is for the left and right
channels. The WS is high for the left channel, and low for the right channel (requires the WS polarity
control bit to be set to 1). A bit clock running at a minimum of 2 x sample width x sample frequency is used
to clock the data. The first data bit appears on the data lines at the same time that LRCK toggles. The data
is written MSB first and is valid on the rising edge of bit clock. When the programmed sample width is
taken, any remaining bits are ignored. If the LRCK toggles before the full word length is read, the
remaining bits are zeroed.
1/fs
L-Channel
R-Channel
1
2
3
N-2 N-1 N
1
LSB
MSB
2
3
N-2 N-1 N
MSB
1
2
LSB
Figure 8: Left-Justified Timing
Right-Justified
Right-justified timing uses the LRCK clock to define when the data being transmitted is for the left and right
channels. The WS is high for the left channel, and low for the right channel (requires the LRCK polarity
control bit to be set to 1). A bit clock running at a minimum of 2 x sample width x sample frequency is used
to clock the data. Data is captured in a 24-bit shift register until LRCK toggles. When LRCK toggles, the
last 24/16/8 bits are transferred to the channel indicated by the previous state of LRCK. In right-justified
mode, the LSB of data is always clocked by the last bit clock before the LRCK transitions. The data is
written MSB first and is valid on the rising edge of bit clock. All leading bits are ignored.
1/fs
L-Channel
14 15 16
1
MSB
2
R-Channel
3
14 15 16
LSB
1
MSB
2
3
14 15 16
LSB
Figure 9: Right-Justified Timing
Conexant Confidential
07/31/14
008DSR00
18
CX20745 Data Sheet
Digital Audio
I2S Timing Transmitter
•
•
•
SCK -> ASCLK (CX20745)
SD - > ASDATA (CX20745)
WS - > ALRCK (CX20745)
T
tRC
tLC > 0.35T
tHC > 0.35T
SCK
thtr > 0
tdtr < 0.8T
SD
and
WS
VH = 2.0V
VL = 0.8V
Figure 10: I2S Transmitter Timing
Note:
•
•
T = Clock period
ttr = Minimum allowed clock period for transmitter T > ttr
•
tRC = Only relevant for transmitter in slave mode
Table 17: Master Transmitter with a Data Rate of 2.5MHz (±10%) (All Values in ns)
Name
Minimum
Typical Maximum Condition
Clock Period T
360
400
440
Ttr = 360
Clock HIGH tHC
160
-
-
Minimum > 0.35T = 140 (at the typical data rate)
Clock LOW tLC
160
-
-
Minimum > 0.35T = 140 (at the typical data rate)
Delay tdtr
-
-
300
Maximum > 0.80T = 320 (at the typical data rate)
Hold Time thtr
100
-
-
Minimum > 0
-
60
Maximum > 0.15Ttr = 54 (only relevant in the slave mode)
Clock Rise Time tRC -
I2S Receiver
•
•
•
SCK - > DSCLK (CX20745)
SD - > DSDATA (CX20745)
WS - > DLRCK (CX20745)
Table 18: Slave Receiver with a Data Rate of 2.5MHz (±10%) (All Values in ns)
Name
Minimum
Typical Maximum Condition
Clock Period T
360
400
440
Ttr = 360
Clock HIGH tHC
110
-
-
Minimum > 0.35T = 126
Clock LOW tLC
110
-
-
Minimum > 0.35T = 126
Setup Time tsr
60
-
-
Minimum > 0.20T = 72
Hold Time thtr
0
-
-
Minimum > 0
Conexant Confidential
07/31/14
008DSR00
19
CX20745 Data Sheet
Digital Audio
PCM
There are three modes of operation for PCM:
•
•
•
Short frame mode
Long frame mode
Multi-slot mode
In short frame mode, the falling edge of PCM_SYNC indicates the start of the PCM word. The PCM_SYNC
is one clock long. Data is driven out on the rising edge of PCM_CLK after the PCM_SYNC pulse.
PCM_SYNC
PCM_CLK
PCM_OUT
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
PCM_IN Undefined 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Undefined
Figure 11: Short Frame Sync (Shown with 16-Bit Sample)
In long frame mode, the rising edge of PCM_SYNC indicates the start of the PCM word. The PCM_SYNC
is at least two clocks long. Data is driven out on the rising edge of PCM_CLK coincident with the rising
edge of PCM_SYNC.
PCM_SYNC
PCM_CLK
PCM_OUT
PCM_IN
Undefined
1
2
3
4
5
6
7
1
2
3
4
5
6
7
8
8
Undefined
Figure 12: Long Frame Sync (Shown with 8-Bit Companded Sample)
In multi-slot mode, PCM_SYNC can be either long or short. Three words of data can be sent or received.
The position of the start of the PCM word is determined by the length of the sync pulse. Slots are
determined by counting data width clocks (8, 16, or 24) from the first PCM word.
Conexant Confidential
07/31/14
008DSR00
20
CX20745 Data Sheet
Digital Audio
Control Interface
The control interface is through a two-wire I2C. The device address is 0x14.
Register Read/Write Operation
Write to a Slave Device
1. Send a start sequence.
2. Send the I2C address of the slave.
3. Send the internal register number you want to write to.
4. Send the data byte.
5. Optional: Send any further data bytes.
6. Perform the burst operation.
7. Send the stop sequence.
Read from a Slave Device
1. Send a start sequence.
2. Send I2C address of the slave.
3. Send the internal address of the bearing register.
4. Send a start sequence again (repeated start).
5. Read the data byte.
6. Send the stop sequence.
Register Address: Transferring Data on the Inter-Integrated Circuit (I2C) Bus
Every byte put on the Serial Data Automation (SDA) line must be eight bits long. The number of bytes that
can be transmitted per transfer is unrestricted. Each byte must be followed by an acknowledge bit. Data is
transferred with the MSB first, as shown in the following figure.
P
SDA
Acknowledgement
Signal from Slave
MSB
Acknowledgement
Signal from Receiver
Sr
Byte Complete
Interrupt within the Slave
Clock Line Held Low While
Interrupts are Serviced
SCL
S
or
Sr
1
2
7
8
9
1
2
ACK
START or
Repeated START
Condition
3-8
9
ACK
Sr
or
P
STOP or
Repeated START
Condition
Figure 13: Transferring Data on I2C
Conexant Confidential
07/31/14
008DSR00
21
CX20745 Data Sheet
Digital Audio
A HIGH to LOW transition on the SDA line while SCL is HIGH is one such unique case. This situation
indicates a START condition. A LOW to HIGH transition on the SDA line while SCL is HIGH defines a
STOP condition. The START and STOP conditions are always generated by the master. The bus is
considered to be busy after the START condition. The bus is considered to be free again a certain time
after the STOP condition. The following figure shows a possible data transfer format.
S
SLAVE ADDRESS
A
R/W
0 (Write)
from Master to Slave
DATA
A
DATA
A/A
P
Data Transferred
(n Bytes + Acknowledge)
A = Acknowledge (SDA LOW)
A = Not Acknowledge (SDA HIGH)
S = START Condition
from Slave to Master
P = STOP Condition
Figure 14: Data Transfer Format
Slave Address Format
The following table shows the slave addressing format for I2C.
Table 19: Slave Addressing Format for I2C
Slave Address
R/W Bit
Description
0000 000
0
General call address.
0000 000
1
START byte.
0000 001
X
CBUS address.
0000 010
X
Reserved for a different bus format.
0000 011
X
Reserved for future purposes.
0000 1XX
X
Hs-mode master code.
1111 1XX
X
Reserved for future purposes.
1111 0XX
X
10-bit slave addressing.
Conexant Confidential
07/31/14
008DSR00
22
CX20745 Data Sheet
Digital Signal Processing (DSP)
I2C Interface 400kHz Timing
The following figure defines the timing of the F/S-mode devices on the I2C bus.
SDA
tLOW
tf
tSU:DAT
tr
tf
tHD:STA
tSP
tBUF
tr
SCL
S
tHD:STA
tHD:DAT
tSU:STA
tHIGH
tSU:STO
P
Sr
S
MSCS10
Figure 15: Definition of Timing for F/S-Mode Devices on the I2C Bus
Table 20: I2C Conditions
I2C (400kHz)
Symbol
Minimum
Maximum
Setup Time Start Condition
tSU.STA
0.6μs
-
Hold Time Start Condition
tHD.STA
0.6μs
-
SCL Clock LOW Period
tLOW
1.3μs
-
SCL Clock HIGH Period
tHIGH
0.6μs
-
Data Setup Time
tSU.DAT
100ns
-
Data Hold Time
tHD.DAT
0
0.9μs
Setup Time for STOP Condition
tSU.STO
0.6μs
-
Digital Signal Processing (DSP)
A DSP system with a digital audio input signal in the range of 0kHz to 20kHz uses oversampling
techniques, and a third order delta-sigma modulator to convert the 8-bit/16-bit/24-bit digital signal at the
following sampling frequencies:
•
•
48kHz/ 96kHz/8kHz/12kHz/16kHz/24kHz/32kHz/ into a multi-bit stream at a rate of 12.288MHz
88.2kHz/44.1kHz/22.05kHz/11.025kHz/8.0182kHz/16.0364kHz into a multi-bit stream at a rate of
11.2896MHz
DAC Digital Filters
I2S
Interface
Digital
Gain
Five
Band
Equalizer
DRC
Digital
Filters
INTERP
SDM
DAC
Figure 16: DAC Digital Section
Conexant Confidential
07/31/14
008DSR00
23
CX20745 Data Sheet
Digital Signal Processing (DSP)
Equalizer (EQ)/Dynamic Range Compressor (DRC)
The CX20745 includes a five-band, bi-quad Infinite Impulse Response (IIR) hardware EQ (with bypass
capability). The function of the EQ is to adjust the frequency characteristics of the output to compensate for
unwanted frequency characteristics in the speakers or ear pieces. The EQ can also be used to tailor the
response according to user preferences. Typical EQ band types include lo-shelf/pass, hi-shelf/pass, and
band-pass/peaking.
Each EQ band stage is a second order IIR filter. Each IIR has five branches that perform multiplication
between the data and coefficients and an accumulator of the products.
Dynamic Range Compression (DRC)
Ou t
C om pSlope
LinGain
T hreshold
In
Figure 17: DRC Threshold
•
•
•
•
•
•
•
Find maximum(abs(sample value)) over a block and convert to dB.
At the quarter block interval, calculate a smoothed max_abs.
If max_abs goes:
– Down (release), slowly increase smoothed max-abs
– Up (attack), set smoothed max_abs to max_abs
If smoothed max-abs is in the linear region, select the linear gain—Otherwise, calculate the gain for
compression.
In the compression region, the preferred function is:
– Out = CompSlope * in + (1 – CompSlope) * Threshold + LinearGain_dB
– Define offset = (1 – CompSlope) * Threshold + LinearGain_dB
– Gain = out – in = CompSlope * in + Offset – in
Update the gain by (New_target_gain – Gain) * GAIN_STEP_FAST to ensure the gain changes are
inaudible.
Convert the dB Gain to Linear.
Multiply the signal by gain, saturate, and then truncate.
Conexant Confidential
07/31/14
008DSR00
24
CX20745 Data Sheet
Digital Signal Processing (DSP)
Digital Microphone Interface (DMIC)
The clock sent to the DMIC device is 3.072MHz and 1.536MHz:
•
•
•
•
•
Two-wire interface (excluding power and ground)—Clock and data
Single bit over the sampled output
Supports stereo operation:
– Left channel outputs on the positive edge of the clock
– Right channel outputs on the negative edge of the clock
Filtering and down sampling (decimation) is done in CODEC
Additional stereo pairs can be added by adding one pin per pair—Shares the same clock
V dd
Cloc k
Data
M IC -L
Au d io
CODEC
M IC -R
Figure 18: DMIC
Table 21: Pins Used
Item No.
Name
Type
Description
1
DMIC_CLK
Digital
Digital microphone clock.
2
DMIC_1/2
Digital
Digital microphone inputs 1 and 2.
Data Input
•
•
VIL-0.3V (minimum) 0.94V (maximum)—Maximum value adjustable using an on-chip comparator
VIH1.2V (minimum) 3.3V (maximum)
Clock Output
•
•
•
•
•
Frequency: 3.072MHz
VOL0.4V (maximum)
VOH2.6V (minimum)—Using full drive output driver capability
VOHadjustable (minimum)—Using open-drain output driver capability
Default drive strength (4mA)
Conexant Confidential
07/31/14
008DSR00
25
CX20745 Data Sheet
Digital Signal Processing (DSP)
Timing Diagram
•
•
Left data = Output by the digital microphone on the rising edge of the digital microphone clock
– Latched by the Conexant device on the falling edge of the digital microphone clock
– Setup time = 36ns
– Hold time = 0ns
Right data = Output by the digital microphone on the falling edge of the digital microphone clock
– Latched by the Conexant device on the rising edge of the digital microphone clock
– Setup time = 36ns
– Hold time = 0ns
Th
Tsu
Digital Mic Clock
Digital Mic Data
Left
Right
Right
Left
Figure 19: DMIC Timing
Automatic Gain Control (AGC) Record Path
DRC
Activity Detected
Activity
Detector
Signal Energy
Gain
Control
Gain
Figure 20: AGC Record Path
The microphone AGC function is supported by three sections:
•
•
•
Activity detector
Gain control
DRC
It is assumed that because the microphone AGC is intended for voice conversation and both channels
have similar energy characteristics, the gain is only calculated on one channel and applied to both
channels.
Conexant Confidential
07/31/14
008DSR00
26
CX20745 Data Sheet
Digital Signal Processing (DSP)
Activity Detector
•
•
•
•
•
•
•
•
The microphone AGC block supports both 16kHz and 8kHz 16-bit samples. For 16kHz mode, samples
are down-sampled to 8kHz by discarding every other sample.
The 8kHz samples are then passed through a first order IIR High-Pass Filter (HPF) (DC rejection).
Power energy and sample squared are summed in the frame energy current block.
Use frame energy to estimate the:
– Signal levels using a fast IIR average filter
– Noise levels using a slow IIR average filter
Has a noise level estimation tracking loop with stability control.
In a noisy environment, the noise power level is clipped to a 1.5 times signal power level.
If the PowerIn to PowerNoise ratio is above a programmable threshold, which signifies a valid block is
detected, then the block frame energy calculated is used to calculate the gain in the gain control block.
To reduce sensitivity due to miss detection, if a valid block is not detected, the transition to detection
OFF is delayed by a programmable number of hysteresis blocks.
Gain Control
•
•
•
Can determine the maximum block frame energy (while the detection is high) from the activity detector
block in the programmable number of blocks.
The sum of the maximum frame energy and gain in dB is used to update the gain. Compare the sum
with the programmable energy threshold high and energy threshold low for decreasing or increasing
the gain, respectively.
Stability logic is used to stabilize the gain from switching between updating the gain up and down too
frequently.
Conexant Confidential
07/31/14
008DSR00
27
CX20745 Data Sheet
Digital Signal Processing (DSP)
General Purpose Input/Output (GPIO) Functions
Rotary Mode
•
•
GPIO1 -> Clockwise (CW) direction
GPIO2 -> Counter Clockwise (CCW) direction
Rotary Encoder
The following figure shows the EC16B encoder that is used for the CX20745, which is manufactured by the
ALPS electricity company in Japan.
Figure 21: Rotary Encoder
The encoder has three terminals—one is allocated for the common terminal (COM), and the other two are
used as a terminal for the output. The output terminal becomes the condition, whether or not it connects
with the common terminal. Two terminals for the output differ in the timing, which touches a common
terminal when the axis of the encoder is turned.
The following figure shows the output relation in the case of EC16B resembles.
Figure 22: Rotary Encoder Block Diagram
Conexant Confidential
07/31/14
008DSR00
28
CX20745 Data Sheet
Digital Signal Processing (DSP)
Table 22: EC16B Standard Data
Item
Description
Pulses/Rotation
24.
Output code
Phase difference of two signals.
Rotational Angle
360°.
Mounting Method
Fastened with a bushing nut.
Ratings
5V DC, 0.5mA.
Maximum Operating Current
0.5mA.
Insulation Resistance
50V DC, 10MΩ minimum.
Withstand Voltage
50V AC.
Sliding Noise
•
•
t: = Masking time to avoid chattering
When R = 100kΩ, t = 5ms
V1 = V2 = 1V maximum
Chattering Prevention Circuit
The chattering prevention circuit is using capacitor (C) to prevent chattering. This phenomenon occurs
when using a mechanical switch. The electronic circuits have detected ON, OFF, and sometimes
malfunctions. When the chattering prevention circuit is not used, more than one count may rise in spite of
being only one count.
The Schmidt trigger-type inverter (7414) uses the Darlington connection circuit, and is used to arrange a
waveform. This circuit connects a collector at the pre-stage with the base at the following stage directly. In
this way, the output turning-over of the inverter becomes high-speed.
Vcc
COM
Rotary
Encoder
R
C
Figure 23: Chattering Prevention Circuit Block Diagram
Conexant Confidential
07/31/14
008DSR00
29
CX20745 Data Sheet
Digital Signal Processing (DSP)
Up/Down Detection Circuit
The up/down detection circuit determines whether it is a CW or CCW operation compared with two pieces
of output from the encoder. This circuit uses a D-type flip-flop (7474) for the determination. The D-type flipflop performs the operation to output the output terminal (Q) in the condition of the D input terminal when
the clock (CK) changes into the H condition from the L condition.
Clockwise (CW) Operation
1. When the A point changes into H from the L, the ICB clock (CK):
• Changes into H from the L
• Becomes the condition to receive the D input
Because the B point is then in the L condition and the clear terminal of ICB is in the L condition, the
ICB output (the Y point) keeps an L condition. Because the clear terminal is always an L when the ICB
clock (the A point) becomes H from the L in the CW, the condition of ICB does not change.
2. The B point changes into H from the L. This changes the ICA clock (CK) from the L to H, and the ICA
becomes the condition to receive the D input. Because the A point becomes the H condition and a
cleared condition is already canceled, the ICA output (the X point) changes into H from the L.
3. An ICA is initialized by the ICA’s clear terminal, the ICA output (the X point) changes into the L from H
when the turn moves ahead, and the A point changes into the L from H.
When moving an encoder to the right in one-click (as described in the previous explanation), one pulse
is output on the X point. In the CW case, the pulse does not develop on the side of the Y point. The
pulse occurs to the X point every time it clicks to the right.
The process also works like the CW in the CCW case—because the B point changes into H from the L
earlier than the A point, the pulse does not develop on the side of the X point. The pulse occurs to the
Y point every time it clicks to the left.
Through this operation, the circuit does the judgment of the CW and the CCW, and the pulse occurs at
each output terminal every time it clicks.
Conexant Confidential
07/31/14
008DSR00
30
CX20745 Data Sheet
Digital Signal Processing (DSP)
Figure 24: Up/Down Detection Circuit
Push Button Mode
•
•
GPIO1 -> Volume up
GPIO2 -> Volume down
The option for continuous push on GPIO1 or GPIO2 causes the volume to be incremented or decremented
at a fixed rate.
Conexant Confidential
07/31/14
008DSR00
31
CX20745 Data Sheet
Clocking
GPIO 3
Events Requiring an Interrupt to the Host
•
•
•
•
Class-D error events
Jack sense change events
Head set volume change
Rotary volume change
Scheme
•
•
•
•
•
•
•
All events are stored in a read-only register
Any change in the status register is gated with an associated interrupt enable signal
Event changes are stored in the corresponding status register
The host receives the interrupt immediately
Because the interrupt status register is a sticky 1, the interrupt signal remains high until the host is
freed to clear the event
The host should read the event change register when it receives the interrupt, and can then read the
information of the event from the individual status register
The host must clear the interrupt status register by writing a 1 to the corresponding register
GPIO 4
The GPIO pin under the driver control can be used to observe whether AGC and speaker DRC are in the
compression region.
Clocking
Clock Inputs
The following table defines the CX20745 clock inputs.
Table 23: Clock Inputs
Number
Clock
Frequency (Maximum)
1
MCLK
24.576MHz
2
DSCLK
6.144MHz
3
ASCLK
3.072MHz
Note: The MCLK clock must be a derivative of I2S bit clocks for proper operation.
Conexant Confidential
07/31/14
008DSR00
32
CX20745 Data Sheet
Registers
Registers
Register Summary
Note: Registers are in the analog domain.
Table 24: Register Summary
Register Name
Offset (Byte)
Default
Equalizer Crossover Enable/Bypass Control
0x00
0x00
EQ Coeff B0 High
0x01
0x00
CODEC Control Registers
EQ Coeff B0 Low
0x02
0x00
EQ Coeff B1 High
0x03
0x00
EQ Coeff B1 Low
0x04
0x00
EQ Coeff B2 High
0x05
0x00
EQ Coeff B2 Low
0x06
0x00
EQ Coeff A1 High
0x07
0x00
EQ Coeff A1 Low
0x08
0x00
EQ Coeff A2 High
0x09
0x00
EQ Coeff A2 Low
0x0A
0x00
Gain
0x0B
0x00
EQ Coef Load Control
0x0C
0x00
DRC_Gain High
0x0D
0x00
DRC_Gain Low
0x0E
0x00
DAC Sample Rate and Enables
0x0F
0x00
DAC Left Channel Volume Control
0x10
0x4A
DAC Right Channel Volume Control
0x11
0x4A
Digital Microphone Enables and Gain
0x12
0x02
ADC Sample Rate and Enables
0x13
0x00
ADC Left Channel Volume Control
0x14
0x4A
ADC Right Channel Volume Control
0x15
0x4A
HP Control
0x16
0x3F
Line-out Control
0x17
0x77
Speaker Control
0x18
0x07
Analog ADC Left Channel Control
0x19
0x00
Analog ADC Right Channel Control
0x1A
0x00
Micbias Control
0x1B
0x00
I2S Tx Control 1
0x1C
0x00
I2S Tx Control 2
0x1D
0x00
I2S Rx Control 1
0x1E
0x00
I2S Rx Control 2
0x1F
0x00
Data Intermediate Frequency (IF) Registers
Conexant Confidential
07/31/14
008DSR00
33
CX20745 Data Sheet
Register Summary
Table 24: Register Summary (Continued)
Register Name
Offset (Byte)
Default
I2S_PCM Control 1
0x20
0x00
I2S _PCM Control 2
0x21
0x00
PCM Tx Control 1
0x22
0x00
PCM Tx Control 2
0x23
0x00
PCM Tx Control 3
0x24
0x00
PCM Rx Control 1
0x25
0x00
PCM Rx Control 2
0x26
0x00
PCM Rx Control 3
0x27
0x00
0x28
0xC0
Activity Detect Beta Voice Shift
0x29
0x02
Activity Detect Beta Noise Shift
0x2A
0x0B
Activity Detect Test Gain
0x2B
0x00
Activity Detect Release Delay MSB
0x2C
0x01
Activity Detect Release Delay LSB
0x2D
0x2C
Activity Detect Power in Initial Value MSB
0x2E
0x0A
Activity Detect Power in Initial Value LSB
0x2F
0x3D
Activity Detect Minimum SNR MSB
0x30
0x09
AGC Registers
Activity Detect DC Reject Pole
Activity Detect Minimum SNR LSB
0x31
0x00
AGC Volume Ramp Step
0x32
0x08
Activity Detect Power Noise Initial Value MSB
0x33
0xE9
Activity Detect Power Noise Initial Value LSB
0x34
0x00
Activity Detect Minimum Threshold MSB
0x35
0xC1
Activity Detect Minimum Threshold LSB
0x36
0x00
Activity Detect ON2OFF Delay
0x37
0x14
AGC Update Block
0x38
0x0A
AGC Energy Threshold Lo MSB
0x39
0xE8
AGC Energy Threshold Hi
0x3A
0xF7
AGC Stability Blocks
0x3B
0x3C
AGC Step-up
0x3C
0x12
AGC Step-down MSB
0x3D
0xEE
AGC Stability Counter Positive Inc
0x3E
0x01
AGC Stability Counter Negative Inc
0x3F
0x0C
DRC Release Delay
0x40
0x40
DRC Gain Step Slow
0x41
0x10
DRC Gain Step Fast
0x42
0x40
DRC Maximum Line-out
0x43
0xE0
DRC Gain Shift
0x44
0x05
DRC Maximum Absolute Initial Value
0x45
0x3A
AGC Gain Initial Value
0x46
0x00
Conexant Confidential
07/31/14
008DSR00
34
CX20745 Data Sheet
Register Summary
Table 24: Register Summary (Continued)
Register Name
Offset (Byte)
Default
DRC Output Limit
0x47
0x00
AGC Clipping Threshold
0x48
0xF9
DAC_HP_CNTRL
0x59
0x04
Line-in Loop (I S) Gain
0x5A
0x00
Volume GPIO
0x5B
0x3C
Volume Control
0x5C
0x00
Interrupt Enable
0x5D
0x00
Interrupt Status
0x5E
0x00
SPKR_DRC_ATTACK_UPDATE_STEP
0x64
0x80
SPKR_DRC_RELEASE_UPDATE_STEP
0x65
0x10
SPKR_DRC_RELEASE_DELAY
0x66
0x40
SPKR_DRC_TRANSIENT_UPDATE_STEP
0x67
0x20
SPKR_DRC_TRANSIENT_RELEASE_DELAY
0x68
0x40
SPKR_DRC_BOOST_DB LSB
0x69
0x00
SPKR_DRC_BOOST_DB MSB
0x6A
0x00
SPKR_DRC_MAX_LIN_OUT_DBFS_MSB
0x6B
0x00
SPKR_DRC_MAX_LIN_OUT_DBFS_LSB
0x6C
0x00
SPKR_DRC_OUT_LIMIT_DB_MSB
0x6D
0x00
SPKR_DRC_OUT_LIMIT_DB_LSB
0x6E
0x00
SPKR_DRC_IN_LIMIT_DB MSB
0x6F
0x00
SPKR_DRC_IN_LIMIT_DB LSB
0x70
0x00
2
SPKR_DRC_BALANCE_RAMP_STEP_MSB
0x71
0x00
SPKR_DRC_BALANCE_RAMP_STEP_LSB
0x72
0x20
SPKR_DRC_GAIN_SHIFT
0x73
0x04
SPKR_DRC_MAXABS_INITVAL
0x74
0x34
SPKR_DRC_VOLUME_RAMP_STEP
0x75
0x03
SPKR_DRC_MAX_RAMP_STEP_SHIFT
0x76
0x0A
SPKR_DRC_RELEASE_RATE_TH
0x77
0x00
Read-Only Registers
Jack Status and Bond Option
0xE3
0x00
Class-D Protection Status
0xE4
0x00
Class-D Calibration Observe
0xE5
0x20
HP A Offset Calibration Observe
0xE6
0x40
HP B Offset Calibration Observe
0xE7
0x40
BIST Read Status
0xE8
0x00
AGC Gain-out LSB
0xE9
0x00
AGC Gain-out MSB
0xEA
0x00
SPKR DRC Gain LSB
0xEB
0x00
SPKR DRC Gain MSB
0xEC
0x00
Micbias Detect
0xED
0x40
Conexant Confidential
07/31/14
008DSR00
35
CX20745 Data Sheet
Register Summary
Table 24: Register Summary (Continued)
Register Name
Offset (Byte)
Default
0xF1
0x00
GPIO Registers
GPIO IN
GPIO OUT
0xF2
0x00
GPIO Direction
0xF3
0x00
GPIO Control
0xF4
0xC7
I2S_data Out Control
0xF5
0xFF
DMIC Control
0xF6
0x0D
Device ID LSB
0xFD
0x07
Device ID MSB
0xFE
0x51
Bond Pad Read Status
0xFF
-
Digital Test 0
0x80
0x00
Digital Test 1
0x81
0x00
Digital Test 2
0x82
0x00
Digital Test 3
0x83
0x80
Digital Test 4
0x84
0x00
Digital Test 5
0x85
0x00
CODEC Test 0
0x88
0x00
CODEC Test 1
0x89
0x00
CODEC Test 2
0x8A
0x00
CODEC Test 3
0x8B
0x0F
CODEC Test 4
0x8C
0x00
CODEC Test 5
0x8D
0x20
CODEC Test 6
0x8E
0x04
CODEC Test 7
0x8F
0x00
CODEC Test 8
0x90
0x00
Test Registers
CODEC Test 9
0x91
0x00
CODEC Test 10
0x92
0x30
CODEC Test 11
0x93
0x00
CODEC Test 12
0x94
0x00
CODEC Test 13
0x95
0x06
CODEC Test 14
0x96
0x20
CODEC Test 15
0x97
0x00
CODEC Test 16
0x98
0x20
CODEC Test 17
0x99
0x00
CODEC Test 18
0x9A
0x00
CODEC Test 19
0x9B
0x00
CODEC Test 20
0x9C
0x00
CODEC Test 21
0x9D
0x00
CODEC Test 22
0x9E
0x04
Conexant Confidential
07/31/14
008DSR00
36
CX20745 Data Sheet
Register Summary
Table 24: Register Summary (Continued)
Register Name
Offset (Byte)
Default
CODEC Test 23
0x9F
0xA2
Analog Test 0
0xA4
0x00
Analog Test 1
0xA5
0x00
Analog Test 2
0xA6
0x00
Analog Test 3
0xA7
0x00
Analog Test 4
0xA8
0x00
Analog Test 5
0xA9
0xA0
Analog Test 6
0xAA
0x00
Analog Test 7
0xAB
0x00
Analog Test 8
0xAC
0x00
Analog Test 9
0xAD
0x00
Analog Test 10
0xAE
0x00
Analog Test 11
0xAF
0x00
Analog Test 12
0xB0
0x00
Analog Test 13
0xB1
0x0F
Analog Test 14
0xB2
0x19
Analog Test 15
0xB3
0x00
Analog Test 16
0xB4
0x00
Analog Test 17
0xB5
0x00
Analog Test 18
0xB6
0x00
Analog Test 19
0xB7
0x00
Analog Test 20
0xB8
0x00
Analog Test 21
0xB9
0x00
Analog Test 22
0xBA
0x00
Analog Test 23
0xBB
0x00
Analog Test 24
0xBC
0x00
Analog Test 25
0xBD
0x00
Analog Test 26
0xBE
0x00
Analog Test 27
0xBF
0x00
Analog Test 28
0xC0
0x00
Analog Test 29
0xC1
0x00
Analog Test 30
0xC2
0x00
Analog Test 31
0xC3
0x50
Analog Test 32
0xC4
0x00
Analog Test 33
0xC5
0x00
Analog Test 34
0xC6
0x00
Analog Test 35
0xC7
0x00
Analog Test 36
0xC8
0x01
Analog Test 37
0xC9
0x00
Analog Test 38
0xCA
0x00
Conexant Confidential
07/31/14
008DSR00
37
CX20745 Data Sheet
Register Details
Table 24: Register Summary (Continued)
Register Name
Offset (Byte)
Default
Analog Test 39
0xCB
0x00
Analog Test 40
0xCC
0x00
Analog Test 41
0xCD
0x01
Analog Test 42
0xCE
0x01
Analog Test 43
0xCF
0x00
Analog Test 44
0xD0
0x00
Analog Test 45
0xD1
0x00
Analog Test 46
0xD2
0x00
Analog Test 47
0xD3
0x00
Analog Test 48
0xD4
0x00
Analog Test 49
0xD5
0x00
Analog Test 50
0xD6
0x00
Analog Test 51
0xD7
0x00
Register Details
Coder-Decoder (CODEC) Control Registers
Table 25: Equalizer Crossover Enable Bypass (0x00)
Bits
Name
7:4
Default
R/W
Description
Reserved
R
Reserved.
3
Bypass 2
R/W
0 = Bypass equalizer/crossover in DAC2.
2
Bypass 1
R/W
0 = Bypass equalizer/crossover in DAC1.
1
Enable 2
R/W
1 = Enable equalizer/crossover in DAC2.
0
Enable 1
R/W
1 = Enable equalizer/crossover in DAC1.
0x00
Table 26: Equalizer Coefficient B0 High (0x01)
Bits
Name
Default
R/W
Description
7:0
Coefficient High Byte
0x00
R/W
CODEC IIR B0 feed forward coefficient high byte.
Table 27: Equalizer Coefficient B0 Low (0x02)
Bits
Name
Default
R/W
Description
7:0
Coefficient Low Byte
0x00
R/W
CODEC IIR B0 feed forward coefficient low byte.
Table 28: Equalizer Coefficient B1 High (0x03)
Bits
Name
Default
R/W
Description
7:0
Coefficient High Byte
0x00
R/W
CODEC IIR B1 feed forward coefficient high byte.
Conexant Confidential
07/31/14
008DSR00
38
CX20745 Data Sheet
Register Details
Table 29: Equalizer Coefficient B1 Low (0x04)
Bits
Name
Default
R/W
Description
7:0
Coefficient Low Byte
0x00
R/W
CODEC IIR B1 feed forward coefficient low byte.
Table 30: Equalizer Coefficient B2 High (0x05)
Bits
Name
Default
R/W
Description
7:0
Coefficient High Byte
0x00
R/W
CODEC IIR B2 feed forward coefficient high byte.
Table 31: Equalizer Coefficient B2 Low (0x06)
Bits
Name
Default
R/W
Description
7:0
Coefficient Low Byte
0x00
R/W
CODEC IIR B2 feed forward coefficient low byte.
Table 32: Equalizer Coefficient A0 High (0x07)
Bits
Name
Default
R/W
Description
7:0
Coefficient High Byte
0x00
R/W
CODEC IIR A0 feedback coefficient high byte.
Table 33: Equalizer Coefficient A0 Low (0x08)
Bits
Name
Default
R/W
Description
7:0
Coefficient Low Byte
0x00
R/W
CODEC IIR A0 feedback coefficient low byte.
Table 34: Equalizer Coefficient A1 High (0x09)
Bits
Name
Default
R/W
Description
7:0
Coefficient High Byte
0x00
R/W
CODEC IIR A1 feedback coefficient high byte.
Table 35: Equalizer Coefficient A1 Low (0x0A)
Bits
Name
Default
R/W
Description
7:0
Coefficient Low Byte
0x00
R/W
CODEC IIR A1 feedback coefficient low byte.
Default
Table 36: Gain (0x0B)
Bits
Name
R/W
Description
7:3
Reserved
R
Reserved.
2:0
Gain
R/W
CODEC IIR output gain
• 000b = –12dB
• 001b = –6dB
• 010b = 0dB
• 011b = 6dB
• 100b = 12dB
• 101b = 18dB
0x00
Conexant Confidential
07/31/14
008DSR00
39
CX20745 Data Sheet
Register Details
Table 37: Coeff Load Control (0x0C)
Bits
Name
R/W
Description
7
Coeff_Done
Default
R
The IIR is done with loading, so the next IIR
coefficient set can be loaded.
6
Coeff_Latch_En
R/W
Set to 1 to indicate the coefficient set is complete and
ready to load to the IIR. The bit is reset by a hardware
function when Coeff_Done is asserted (so no
firmware action is required to turn off this bit).
5:4
Coeff_CH
R/W
Selects which IIR channel is to be loaded
• 00b = DAC_L
• 01b = DAC_R
• 10b = DAC_Mono
• 11b = Reserved
R/W
Selects which IIR is to be loaded
• 0000b = IIR 0
• 0001b = IIR 1
• 0010b = IIR 2
• ...
• 1001b = IIR 9
• 1010b = IIR A
• 1011b = IIR B
• 1100b = DRC_G
0x00
3:0
Coeff_IIR
Table 38: DRC_Gain High (0x0D)
Bits
Name
Default
R/W
Description
7:0
DRC_Gain High Byte
0x00
R/W
CODEC final DRC gain high byte.
Table 39: DRC_Gain Low (0x0E)
Bits
Name
Default
R/W
Description
7:0
DRC_Gain Low Byte
0x00
R/W
CODEC final DRC gain high byte.
Conexant Confidential
07/31/14
008DSR00
40
CX20745 Data Sheet
Register Details
Table 40: DAC 1:2 Sample Size/Rate (0x0F)
Bits
Name
7:4
DAC 1:2 Sample Rate
Default
R/W
Description
R/W
•
•
•
•
•
•
•
•
•
•
•
•
•
•
0x00
0x0 = 8K
0x1 = 12K
0x2 = 16K
0x3 = 24K
0x4 = 32K
0x5 = 48K
0x6 = 96K
0x8 = 8.0182K
0x9 = 11.025K
0xA = 16.0364K
0xB = 22.05K
0xC = 44.1K
0xE = 88.2K
Others = Reserved
3
Reserved
R
Reserved.
2
DAC Swap Enable
R/W
Enables the swap enable.
1
DAC 2 Enable
R/W
Enables DAC2 or the right channel.
0
DAC 1 Enable
R/W
Enables DAC1 or the left channel.
Table 41: DAC 1 (Left Channel) Volume/Mute Control (0x10)
Bits
Name
Default
R/W
Description
7
DAC 1 Mute
1 = Mutes DAC 1 (left channel).
6:0
DAC 1 Volume
Programmable gain stage in digital
• 0x50 = 6dB
• 0x4F = 5dB
• 0x4E = 4dB
• 0x4D = 3dB
• 0x4C = 2dB
• …
• 0x3 = –71dB
• 0x2 = –72dB
• 0x1 = –73dB
• 0x0 = –74dB
0x4A
R/W
Conexant Confidential
07/31/14
008DSR00
41
CX20745 Data Sheet
Register Details
Table 42: DAC 2 (Right Channel) Volume/Mute Control (0x11)
Bits
Name
Default
7
DAC 2 Mute
1 = Mutes DAC 2.
6:0
DAC 2 Volume
Programmable gain stage in digital
• 0x50 = 6dB
• 0x4F = 5dB
• 0x4E = 4dB
• 0x4D = 3dB
• 0x4C = 2dB
• …
• 0x03 = –71dB
• 0x02 = –72dB
• 0x01 = –73dB
• 0x00 = –74dB
0x4A
R/W
Description
R/W
Table 43: Digital Microphone Control (0x12)
Bits
Name
7:5
Digital Microphone Right
Channel Gain
4:2
Digital Microphone Left
Channel Gain
Default
0x02
R/W
R/W
Description
•
•
•
•
•
000b = 0dB
001b = 12dB
010b = 24dB
011b = 36dB
100b = 48dB
•
•
•
•
•
000b = 0dB
001b = 12dB
010b = 24dB
011b = 36dB
100b = 48dB
1
Digital Power Down
Disables the DMIC with the clock stopped and the
microphone pad powered down.
0
Digital Input Enable
Mutes the DMIC.
Conexant Confidential
07/31/14
008DSR00
42
CX20745 Data Sheet
Register Details
Table 44: ADC Sample Rate/Enable Register (0x13)
Bits
Name
7:4
ADC Sample Rate
Default
0x00
R/W
R/W
Description
•
•
•
•
•
•
•
•
•
•
•
•
0000b = 8K
0001b = 12K
0010b = 16K
0011b = 24K
0100b = 32K
0101b = 48K
1000b = 8.0182K
1001b = 11.025K
1010b = 16.0364K
1011b = 22.05K
1101b = 44.1K
Others = Reserved
3
ADC Swap
Swaps the left and right channel.
2
Agc_en
Enables the AGC block.
1
ADC Connection Index
•
•
0
ADC Enable
Enables the ADC stereo.
0 = Analog microphone
1 = Digital microphone
Table 45: ADC Left Channel Volume/Mute Control (0x14)
Bits
Name
Default
7
ADC Left Channel Mute
1 = Mutes the DAC left channel.
6:0
ADC Left Channel Volume
Programmable gain stage in digital
• 0x50 = 6dB
• 0x4F = 5dB
• 0x4E = 4dB
• 0x4D = 3dB
• 0x4C = 2dB
• …
• 0x03 = –71dB
• 0x02 = –72dB
• 0x01 = –73dB
• 0x00 = –74dB
0x4A
R/W
R/W
Description
Conexant Confidential
07/31/14
008DSR00
43
CX20745 Data Sheet
Register Details
Table 46: ADC Right Channel Volume/Mute Control (0x15)
Bits
Name
7
ADC Right Channel Mute
Default
1 = Mutes the ADC right channel.
6:0
ADC Right Volume
Programmable gain stage in digital
• 0x4F = 5dB
• 0x4E = 4dB
• 0x4D = 3dB
• 0x4C = 2dB
• …
• 0x03 = –71dB
• 0x02 = –72dB
• 0x01 = –73dB
• 0x00 = –74dB
0x4A
R/W
R/W
Description
Table 47: HP Control Register (0x16)
Bits
Name
Default
7:6
Reserved
Reserved.
5
HP B Output Enable
•
•
4:3
HP B Pwr
HP B power state
• 11b = D3
• 10b = D2
• 01b = D1
• 00b = D0
0x3F
R/W
R/W
Description
1 = Enables the HP B output
0 = Disable
2
HP A Output Enable
•
•
1 = Enables the HP A output
0 = Disable
1:0
HP A Pwr
HP A power state
• 11b = D3
• 10b = D2
• 01b = D1
• 00b = D0
Conexant Confidential
07/31/14
008DSR00
44
CX20745 Data Sheet
Register Details
Table 48: Line-Out Control Register (0x17)
Bits
Name
7
Reserved
Default
R/W
Reserved.
6
Line-out 2 Enable
•
•
5:4
Line-out 2 Pwr
Line-out two power state
• 11b = D3
• 10b = D2
• 01b = D1
• 00b = D0
3
Reserved
2
Line-out 1 Enable
•
•
1:0
Line-out 1 Pwr
Line-out one power state
• 11b = D3
• 10b = D2
• 01b = D1
• 00b = D0
0x77
Description
R/W
0 = Disable
1 = Line-out two-output enable
Reserved.
0 = Disable
1 = Line-out one output enable
Table 49: SPKR Control Registers (0x18)
Bits
Name
Default
R/W
7:5
Reserved
Reserved.
4
Spkr pwm_en i
1 = Enables the speaker PWM that is enabled from
the input.
3
Spkr Mono Mode
1 = Enables the speaker mono mode.
2
Spkr Output Enable
1:0
Spkr Power
0x07
Description
1 = Speaker output enable.
R/W
Speaker power state
• 11b = D3
• 10b = D2
• 01b = D1
• 00b = D0
Table 50: ADC Analog Left Channel Control Register (0x19)
Bits
Name
7
Default
R/W
Description
ana_adc_l_mute
R/W
1 = Mutes the analog ADC left channel.
6:5
Reserved
R
Reserved.
4
Monitor Mode
R/W
1 = Enables the monitor mode with one ADC channel
dedicated for the monitor.
3:1
Ana_adc_l_gain
R/W
Gain for the analog ADC.
0
Ana_adc_l_en
R/W
1 = Enables the analog ADC left channel.
0x00
Conexant Confidential
07/31/14
008DSR00
45
CX20745 Data Sheet
Register Details
Table 51: ADC Analog Right Channels Control Register (0x1A)
Bits
Name
Default
7
Adc_diffen
1 = Enables the differential input on the ADC.
6:5
Ana_adc_sel
Selects the input to the ADC
• 00b = Input is the line-in/microphone-in
• 01b = Input is the volt monitor
• 10b = Input is the volume
0x00
R/W
R/W
Description
4
Ana_adc_r_mute
1 = Mutes the analog ADC right channel.
3:1
Ana_adc_r_gain
Gain for the analog ADC.
0
Ana_adc_r_en
1 = Enables the analog ADC left channel.
Table 52: Micbias Control Register (0x1B)
Bits
Name
7:2
Reserved
1
Micbias Set
0
Micbias En
Default
R/W
Description
0x00
R/W
1 = Sets the micbias.
Reserved.
1 = Enables the micbias.
Data I/F Registers
Table 53: I2S Transmitter Control-1 (0x1C)
Bits
Name
Default
7
I2s_tx_en
Enables the I2S transmitter if the PCM is set.
6:3
Reserved
Reserved.
2
Tx_right_just
1
Tx_mute
Mutes the I2S transmitter (all zeros are sent).
0
Tx_sony_mode
When set, the I2S transmitter works in the Sony mode.
0x00
R/W
R/W
Description
When set, the I2S transmitter works in the right justified
mode.
Table 54: I2S Transmitter Control-2 (0x1D)
Bits
Name
7
Reserved
6:0
Bcnt_del
Default
R/W
0x00
R/W
Description
Reserved.
If right justified, this value indicates the delay for the
first valid data transmitter.
Conexant Confidential
07/31/14
008DSR00
46
CX20745 Data Sheet
Register Details
Table 55: I2S Receiver Control-1 (0x1E)
Bits
Name
Default
7
I2s_rx_en
Enables the I2S receiver if the PCM is set.
6:3
Reserved
Reserved.
3
I2s_rx_en_sh
When set, the host sends the right channel first and
then left channel second.
2
Rx_right_just
1
Rx_mute
Mutes the I2S receiver (all zeros are sent).
0
Rx_sony_mode
When set, then the I2S receiver works in the Sony
mode.
0x00
R/W
R/W
Description
When set, the I2S transmitter works in the right justified
mode.
Table 56: I2S Receiver Control-2 (0x1F)
Bits
Name
7
Reserved
6:0
Bcnt_del
Default
R/W
Description
Reserved.
0x00
R/W
If right justified, this value indicates the delay for the
first valid data on the receiver.
Default
R/W
Description
Table 57: I2S/PCM Control-1 (0x20)
Bits
Name
7:5
Reserved
R
Reserved.
4:3
tx_wdta
R/W
Sets the transmitter data width
• 00b = 8-bit data
• 01b = 16-bit data
• 10b = 24-bit data
2:1
Rx_wdta
R/W
Sets the receiver data width
• 00b = 8-bit data
• 01b = 16-bit data
• 10b = 24-bit data
0
I2S_PCM
R/W
•
•
R/W
Description
0x00
0 = Enables the I2S data interface
1 = Enables the PCM data interface
Table 58: I2S/PCM Control-2 (0x21)
Bits
Name
7:2
Reserved
1
dac_lrck_pol
0
adc_lrck_pol
Default
Reserved.
0x00
R/W
Enables changes to the I2C Rx input LRCK polarity.
Enables changes to the I2C Tx input LRCK polarity.
Conexant Confidential
07/31/14
008DSR00
47
CX20745 Data Sheet
Register Details
Table 59: PCM Transmitter Control-1 (0x22)
Bits
Name
Default
7
Reserved
Reserved.
6
Dshift_sel
•
•
5
Dstart_del
4:0
Txck_sync_rate
0x00
R/W
R/W
Description
1 = LSB is first on the PCM’s Tx and Rx
0 = MSB is first on the PCM’s Tx and Rx
1 = Delays Tx and Rx one cc before sent out/lat.
Specifies the maximum bit count/8–1 between frame
syncs (e.g., set to 0x7 for a two-channel 32-bit stream
or 64-bit between a frame sync [64/8–1]).
Table 60: PCM Transmitter Control-2 (0x23)
Bits
Name
Default
7:3
Tx Slot 1
Indicates which slot number that the left channel needs
to be set to.
2
Tx Out Enable
Enables the PCM Tx output—enable only for the slots
it is driving.
1
Tx2 Enable
0
Tx1 Enable
0x00
R/W
R/W
Description
Enables the right channel if the data interface is set to
the PCM.
Enables the left channel if the data interface is set to
the PCM.
Table 61: PCM Transmitter Control-3 (0x24)
Bits
Name
7:4
Reserved
3:0
Tx Slot 2
Default
R/W
Description
0x00
R/W
Indicates which slot number that the right channel
needs to be set to.
R/W
Description
Reserved.
Table 62: PCM Receiver Control-1 (0x25)
Bits
Name
7:5
Reserved
4:0
Rxck_sync_rate
Default
Reserved.
0x00
R/W
Specifies the maximum bit count/8–1 between frame
syncs (e.g., set to 0x7 for a two-channel 32-bit stream
or 64-bit between a frame sync [64/8–1]).
R/W
Description
Table 63: PCM Receiver Control-2 (0x26)
Bits
Name
Default
7:4
Rx Slot 1
Indicates which slot number that the left channel needs
to be set to.
3:2
Reserved
Reserved.
1
Rx2 Enable
0
Rx1 Enable
0x00
R/W
Enables the right channel if the data interface set to
the PCM.
Enables the left channel if the data interface set to the
PCM.
Conexant Confidential
07/31/14
008DSR00
48
CX20745 Data Sheet
Register Details
Table 64: PCM Receiver Control-3 (0x27)
Bits
Name
7:4
Reserved
3:0
Rx Slot 2
Default
R/W
Description
0x00
R/W
Indicates which slot number that the right channel
needs to be set to.
Reserved.
AGC Registers
Table 65: AD_DC_REJECT_POLE (0x28)
Bits
Name
Default
R/W
Description
7:0
AD_DC_REJECT_POLE
0xC0
R/W
Pole location for the datIn DC rejection IIR filter
Z = AD_DC_REJECT_POLE/215
AD_DC_REJECT_POLE is 16 bits
Bit 14:7 is programmed using this register
represented as 7:0 on the right
Bit 15 is fixed at 0 for a positive-only value
Bit 6 to 0 is fixed at 0
•
•
•
•
•
Table 66: AD_BETA_VOICE SHFT (0x29)
Bits
Name
7:4
3:0
Default
R/W
Description
Reserved
R
Reserved.
AD_BETA_VOICE_SHFT
R/W
•
PowerIn fast averaging IIR filter beta coefficient
•
PowerIn = PowerIn * (1–Beta/215) + FrameEnergy
*(Beta/2^15)
•
Range is 0–15 for a beta range of 2(15–0) to 2(15–
15)
—the default beta is 2(15–2) or 213
0x02
Table 67: AD_BETA_NOISE_SHFT (0x2A)
Bits
Name
7:4
3:0
Default
R/W
Description
Reserved
R
Reserved.
AD_BETA_NOISE_SHFT
R/W
•
PowerNoiseAvg slow averaging IIR filter beta
coefficient
•
PowerNoise = PowerNoise * (1–Beta/215) +
FrameEnergy *(Beta/215)
•
Range is 0–15 for beta range of 2^(15–0) to 2(15–
0x0B
15)
•
Default beta is 2(15–11) or 24
Table 68: AD_TEST_GAIN (0x2B)
Bits
Name
7:4
Reserved
3:0
AD_TEST_GAIN
Default
0x00
R/W
Description
R
Reserved.
R/W
Test only register—left-shift the datIn input signal to
the AGC module by the number of bits specified.
Conexant Confidential
07/31/14
008DSR00
49
CX20745 Data Sheet
Register Details
Table 69: AD_RELEASE_DELAY MSB (0x2C)
Bits
Name
Default
R/W
Description
7:0
AD_RELEASE_DELAY
0x01
R/W
In units of ms—used to program the period of time
passed before allowing the noise-power to increase.
Table 70: AD_RELEASE_DELAY LSB (0x2D)
Bits
Name
Default
R/W
Description
7:0
AD_RELEASE_DELAY
0x2C
R/W
In units of ms—used to program the period of time
passed before allowing the noise-power to increase.
Table 71: AD_POWERIN_INITVAL MSB (0x2E)
Bits
Name
Default
R/W
Description
7:0
AD_POWERIN_INITVAL
0x0A
R/W
PowerIn is a 32-bit voice power register. This register
programs the reset value for bits 30:23 of that
register, represented by 7:0 on the left.
• Bit 31 of the 32-bit register is fixed at 0
• Bits 22:15 are represented by
AD_POWERIN_INITVAL LSB
• Bit 14:0 of the 32-bit register are fixed at 0
Table 72: AD_POWERIN_INITVAL LSB (0x2F)
Bits
Name
Default
R/W
Description
7:0
AD_POWERIN_INITVAL
0x3D
R/W
PowerIn is a 32-bit voice power register. This register
programs the reset value for bits 22:15 of that
register, represented by 7:0 on the left.
• Bit 31 of the 32-bit register is fixed at 0
• Bits 30:23 are represented by
AD_POWERIN_INITVAL MSB
• Bit 14:0 of the 32-bit register are fixed at 0
Table 73: AD_MIN_SNR MSB (0x30)
Bits
Name
Default
R/W
Description
7:0
AD_MIN_SNR
0x09
R/W
AD_MIN_SNR[15:8]—minimum SNR in dB.
Table 74: AD_MIN_SNR LSB (0x31)
Bits
Name
Default
R/W
Description
7:0
AD_MIN_SNR
0x00
R/W
AD_MIN_SNR[7:0]—minimum SNR in dB.
Table 75: AGC_VOLUME_RAMP_STEP (0x32)
Bits Name
Default
R/W
Description
7:0
0x08
R/W
AGC volume ramp step size in dB.
AGC_VOLUME_RAMP_STEP
Conexant Confidential
07/31/14
008DSR00
50
CX20745 Data Sheet
Register Details
Table 76: AD_POWERNOISE_INITVAL MSB (0x33)
Bits Name
Default
R/W
Description
7:0
0xE9
R/W
PowerNoise is a 16-bit noise power register. These
registers program the reset value for [15:8].
AD_POWERNOISE_INITVAL
Table 77: AD_POWERNOISE_INITVAL LSB (0x34)
Bits Name
Default
R/W
Description
7:0
0x00
R/W
PowerNoise is a 16-bit noise power register. These
registers program the reset value for [7:0].
AD_POWERNOISE_INITVAL
Table 78: AD_MIN_THRESH MSB (0x35)
Bits
Name
Default
R/W
Description
7:0
AD_MIN_THRESH
0xC1
R/W
AD_MIN_THRESH [15:8] offset for the decision
threshold to prevent false detection of voice when the
signal is low. This value is 16-bit unsigned.
Table 79: AD_MIN_THRESH LSB (0x36)
Bits
Name
Default
R/W
Description
7:0
AD_MIN_THRESH
0x00
R/W
AD_MIN_THRESH [7:0] offset for the decision
threshold to prevent false detection of voice when the
signal is low. This value is 16-bit unsigned.
Table 80: AD_ON2OFF_DELAY_BLOCKS (0x37)
Bits
Name
7:5
Reserved
4:0
AD_ON2OFF_DELAY_BLOCKS
Default
R/W
Description
R
Reserved.
R/W
On to off delay in number of blocks.
Default
R/W
Description
R
Reserved.
0x0A
R/W
Number of sample blocks used to calculate the
new gain.
0x14
Table 81: AGC_UPDATE_BKS (0x38)
Bits
Name
7:5
Reserved
4:0
AGC_UPDATE_BKS
Table 82: AGC_ENERGY_THRESH_LO MSB (0x39)
Bits
Name
Default
R/W
Description
7:0
AGC_ENERGY_THRESH_LO
0xE8
R/W
Threshold for the decision if the gain needs to be
increased. Only the upper eight bits of the ETMP
value are compared.
Conexant Confidential
07/31/14
008DSR00
51
CX20745 Data Sheet
Register Details
Table 83: AGC_ENERGY_THRESH_HI MSB (0x3A)
Bits
Name
Default
7:0
AGC_ENERGY_THRESH_HI 0xF7
R/W
Description
R/W
Threshold for the decision if the gain needs to be
decreased. Only the upper eight bits of the ETMP
value are compared.
Table 84: AGC_STABILITY_BLOCKS (0x3B)
Bits
Name
7
6:0
Default
R/W
Description
Reserved
R
Reserved.
AGC_STABILITY_BLOCKS 0x3C
R/W
Value compared to the stability counter to ensure the
gain does not oscillate (increase/decrease) too
rapidly.
Table 85: AGC_STEP_UP (0x3C)
Bits
Name
Default
R/W
Description
7:0
AGC_STEP_UP
0x12
R/W
The amount that the gain is to be increased by.
Table 86: AGC_STEP_DOW MSB (0x3D)
Bits
Name
Default
R/W
Description
7:0
AGC_STEP_DOWN
0xEE
R/W
The amount that the gain is to be decreased by.
R/W
Description
R
Reserved.
R/W
The amount that the stability counter is to be
increased by—the range is 0 to 15.
Default
R/W
Description
R
Reserved.
0x0C
R/W
The amount that the stability counter is to be
decreased by—the range is 0 to –16.
Table 87: AGC_STAB_CNT_POS_INC (0x3E)
Bits Name
7:4
3:0
Default
Reserved
AGC_STAB_CNT_POS_INC
0x01
Table 88: AGC_STAB_CNT_NEG_INC (0x3F)
Bits Name
7:4
Reserved
3:0
AGC_STAB_CNT_NEG_INC
Table 89: DRC_RELEASE_DELAY MSB (0x40)
Bits
Name
Default
R/W
Description
7:0
DRC_RELEASE_DELAY
0x40
R/W
In units of 1ms—used to program the period of time
passed before MaxAbsIn can be decreased to a lower
value if the input level is not increasing. Hysteresis for
adjusting the gain upward.
Conexant Confidential
07/31/14
008DSR00
52
CX20745 Data Sheet
Register Details
Table 90: DRC_GAIN_STEP_SLOW (0x41)
Bits
Name
Default
R/W
Description
7:0
DRC_GAIN_STEP_SLOW
0x10
R/W
•
•
•
Coefficient for MaxAbsIn IIR filters the
DRC_GAIN_STEP_SLOW coefficient is 10-bit
unsigned
Programs bit 9:2 of the 10-bit coefficient,
represented on the left by 7:0
Bits 1:0 of the 10-bit coefficient are always fixed
at 0
Table 91: DRC_GAIN_STEP_FAST (0x42)
Bits
Name
Default
R/W
Description
7:0
DRC_GAIN_STEP_FAST
0x40
R/W
•
•
•
Coefficient for the target gain filters
DRC_GAIN_STEP_FAST coefficient is 15-bit
unsigned
Programs bit 14:7 of the 15-bit coefficient,
represented on the left by 7:0
Bits 6:0 of the 15-bit coefficient are fixed at 0
Table 92: DRC_MAX_LIN_OUT (0x43)
Bits
Name
Default
R/W
Description
7:0
DRC_MAX_LIN_OUT
0xE0
R/W
•
•
•
•
Maximum linear output of the DRC—the
DRC_MAX_LIN_OUT is 16-bit signed
Programs bit 11:4 of the 16-bit coefficient,
represented on the left by 7:0
Bits 3:0 of the 16-bit coefficient are fixed at 0
Bits 15:12 of the 16-bit coefficient are fixed at 0xF
Table 93: DRC_GAIN_SHIFT (0x44)
Bits
Name
7:3
Reserved
2:0
DRC_GAIN_SHIFT
Default
R/W
Description
R
Reserved.
0x05
R/W
Gain is in the Q6.10/Q6.26 format, which is a 5-bit
scale-down from Q1.15/Q1.31.
Table 94: DRC_MAXABS_INITVAL (0x45)
Bits
Name
Default
R/W
Description
7:0
DRC_MAXABS_INITVAL
0x3A
R/W
•
•
•
Initial value for MaxAbsIn is
MaxAbsIn = DRC_MAXABS_INITVAL * 2^24;
Initial value for MaxAbsPre is MaxAbsPre =
DRC_MAXABS_INITVAL * 2^8
Range is –32 to 31
Conexant Confidential
07/31/14
008DSR00
53
CX20745 Data Sheet
Register Details
Table 95: AGC_GAIN_INITVAL (0x46)
Bits
Name
Default
R/W
Description
7:0
AGC_GAIN_INITVAL
0x00
R/W
Initial value for the AGC gainctrl gain output to the
microphone DRC.
Table 96: DRC_OUTPUT_LIMIT (0x47)
Bits
Name
Default
R/W
Description
7:0
DRC_OUTPUT_LIMIT
0x00
R/W
DRC output limit. This register programs the eight
MSB bits of 16-bit signed value.
Table 97: AGC_CLIPPING_THRESH (0x48)
Bits
Name
7:0
AGC_CLIPPING_THRESH 0xF9
Default
R/W
Description
R/W
AGC clipping threshold.
R/W
Description
Table 98: DAC_HP_CNTRL (0x59)
Bits
Name
Default
7
Manual Mode HP Enable
When class-D is not mapped to the DAC, the HP can
be enabled on the DAC chain using this bit.
6
Hp_bypass
Bypasses the HP filter on the DAC chain.
5:0
Band Sel [5:0]
Programmable cut-off for the HP
• HPF frequency selection N * 30
• 0x00 = Disabled
• 0x01 = 30Hz
• 0x02 = 60Hz
• …
• 0x3E = 1860Hz
• 0x3F = 1890Hz
0x04
R/W
Conexant Confidential
07/31/14
008DSR00
54
CX20745 Data Sheet
Register Details
Table 99: Line In Loop (I2S Input) Gain Control (0x5A)
Bits
Name
Default
7
Sum_r_mute
Mutes the right channel data from the I2S.
6:4
Sum_r_gain
Gain on the input data from the I2S right channel
before going to the mixer
• 000b = 1.9dB
• 001b = 0dB
• 010b = –2.5dB
• 011b = –6dB
• 100b = –12dB
• 101b = –24dB
• 110b = –36dB
• 111b = –48dB
3
Sum_l_mute
2:0
Sum_l_gain
0x00
R/W
R/W
Description
Mutes the left channel data from the I2S.
Gain on the input data from the I2S right channel
before going to the mixer
• 000b = 1.9dB
• 001b = 0dB
• 010b = –2.5dB
• 011b = –6dB
• 100b = –12dB
• 101b = –24dB
• 110b = –36dB
• 111b = –48dB
Table 100: Volume GPIO Control (0x5B)
Bits
Name
7
Reserved
6:0
Vol_direct
Default
0x3C
R/W
Description
R
Reserved.
R/W
Host can write and read the updated volume.
Table 101: Volume Control (0x5C)
Bits
Name
7:6
Default
R/W
Description
Reserved
R
Reserved.
5
Rotary Edge Pulse
R/W
Sets the rotary detection to the pulse and edge mode
• 0 = Pulse mode
• 1 = Edge mode
4
Vol_en
R/W
Enables the volume control through the GPIO
bypassing register control.
3:1
Vol_deb_time
R/W
Selects the de-bounce time required on the GPIO
pins—increments by every 10ms.
0
Rotary Mode
R/W
Selects whether the volume control is to be rotary or
push up/down.
0x00
Conexant Confidential
07/31/14
008DSR00
55
CX20745 Data Sheet
Register Details
Table 102: Interrupt Enable (0x5D)
Bits
Name
R/W
Description
7:5
Reserved
Default
R
Reserved.
4
Interrupt_en [4]
R/W
Enables the interrupt on the rotary or push button
volume change.
3
Interrupt_en [3]
R/W
Enables the interrupt on the headset’s volume
change.
0x00
2
Interrupt_en [2]
R/W
Enables the interrupt on the jack sense status
change.
1
Interrupt_en [1]
R/W
Enables the interrupt on class-D errors.
0
Interrupt_en [0]
R/W
Reserved.
R/W
Description
Table 103: Interrupt Status (0x5E)
Bits
Name
Default
7:5
Reserved
R
Reserved.
4
Interrupt_status [4]
R/W
Interrupt status on the rotary or push button volume
change.
3
Interrupt_status [3]
R/W
Interrupt status on the headset volume change.
2
Interrupt_status [2]
R/W
Interrupt status on the jack sense status change.
1
Interrupt_status [1]
R/W
Interrupt status for class-D errors.
0
Interrupt_status [0]
R/W
Reserved.
0x00
Table 104: SPKR_DRC_ATTACK_UPDATE_STEP (0x64)
Bits Name
7:0
Default R/W Description
SPKR_DRC_ATTACK_UPDATE_STEP 0x80
R/W Used to program the gain step required to compress
the incoming signal in the compression region.
Table 105: SPKR_DRC_RELEASE_UPDATE_STEP (0x65)
Bits Name
7:0
Default R/W Description
SPKR_DRC_RELEASE_UPDATE_STEP 0x10
R/W Used to program the gain step required to release
the gain slowly when the signal is in the linear
region.
Table 106: SPKR_DRC_RELEASE_DELAY (0x66)
Bits Name
Default
R/W
Description
7:0
0x40
R/W
In units of 1ms—used to program the period of time
passed before MaxAbsIn can be decreased to a
lower value if the input level is not increasing.
Hysteresis for adjusting the gain upward.
SPKR_DRC_RELEASE_DELAY
Conexant Confidential
07/31/14
008DSR00
56
CX20745 Data Sheet
Register Details
Table 107: SPKR_DRC_TRANSIENT_UPDATE_STEP (0x67)
Bits Name
7:0
Default R/W Description
SPKR_DRC_TRANSIENT_UPDATE_STEP 0x20
R/W Used to:
• Program the step value
• Quickly update the MAXABS IN value
Table 108: SPKR_DRC_TRANSIENT_RELEASE_DELAY (0x68)
Bits Name
7:0
Default R/W Description
SPKR_DRC_TRANSIENT_RELEASE_DELAY 0x40
R/W Used to:
• Program the release delay value
• Update the release delay value to make a
quick transition in the gain value
Table 109: SPKR_DRC_BOOST_DB MSB (0x69)
Bits Name
1:0
Default
SPKR_DRC_BOOST_DB[9:8] 0x00
R/W
Description
R/W
The gain value initially set for the DRC.
Table 110: SPKR_DRC_BOOST_DB LSB (0x6A)
Bits Name
Default
R/W
Description
7:0
0x00
R/W
The gain value initially set for the DRC.
SPKR_DRC_BOOST_DB[7:0]
Table 111: SPKR_DRC_MAX_LIN_OUT_DBFS MSB (0x6B)
Bits Name
1:0
Default R/W Description
SPKR_DRC_MAX_LIN_OUT_DBFS[9:8] 0x00
R/W Used to set the threshold and limit values.
Table 112: SPKR_DRC_MAX_LIN_OUT_DBFS LSB (0x6C)
Bits Name
Default R/W Description
7:0
0x00
SPKR_DRC_MAX_LIN_OUT_DBFS[7:0]
R/W Used to set the threshold and limit values.
Table 113: SPKR_DRC_OUT_LIMIT_DBFS MSB (0x6D)
Bits Name
1:0
Default
SPKR_DRC_OUT_LIMIT_DBFS [9:8] 0x00
R/W
Description
R/W
Used to set the DRC output limit.
R/W
Description
R/W
Used to set the DRC output limit.
Table 114: SPKR_DRC_OUT_LIMIT_DBFS LSB (0x6E)
Bits Name
7:0
Default
SPKR_DRC_OUT_LIMIT_DBFS [7:0] 0x00
Conexant Confidential
07/31/14
008DSR00
57
CX20745 Data Sheet
Register Details
Table 115: SPKR_DRC_IN_LIMIT_DB MSB (0x6F)
Bits Name
1:0
Default R/W Description
SPKR_DRC_IN_LIMIT_DB[7:0] 0x00
R/W Used to check if the input signal has reached the limit value.
Table 116: SPKR_DRC_IN_LIMIT_DB LSB (0x70)
Bits Name
7:0
Default R/W Description
SPKR_DRC_IN_LIMIT_DB[2:0] 0x00
R/W Used to check if the input signal has reached the limit value.
Table 117: SPKR_DRC_BALANCE_RAMP_STEP MSB (0x71)
Bits Name
Default R/W Description
1:0
0x00
SPKR_DRC_BALANCE_RAMP_STEP[9:8]
R/W Determines the balance RAMP STEP.
Table 118: SPKR_DRC_COMP_RATIO LSB (0x72)
Bits Name
Default R/W Description
7:0
0x20
SPKR_DRC_BALANCE_RAMP_STEP [7:0]
R/W Determines the balance RAMP STEP.
Table 119: SPKR_DRC_GAIN_SHIFT (0x73)
Bits
Name
Default
R/W
Description
2:0
DRC_GAIN_SHIFT
0x04
R/W
Gain shift value.
Table 120: SPKR_DRC_MAXABS_INITVAL (0x74)
Bits
Name
7
SPKR_DRC_EN
Default
R/W
Enable for the SPKR DRC.
6
DRC_REL_RATE_TH_DISABLE
•
•
0 = Release threshold used
1 = Release threshold not used
5:0
DRC_MAXABS_INITVAL
•
Initial value for MaxAbsIn is
MaxAbsIn = DRC_MAXABS_INITVAL * 2^24
Initial value for MaxAbsPre is MaxAbsPre =
DRC_MAXABS_INITVAL * 2^8
Range is –32 to 31
0x34
R/W
Description
•
•
Table 121: SPKR_DRC_VOLUME_RAMP_STEP (0x75)
Bits
Name
Default
R/W
Description
7:0
DRC_VOLUME_RAMP_STEP
0x03
R/W
Step-size for volume ramping.
Table 122: SPKR_DRC_MAX_RAMP_STEP_SHIFT (0x76)
Bits
Name
Default
R/W
Description
2:0
DRC_MAX_RAMP_STEP_SHIFT
0x0A
R/W
Maximum shift of step-size for volume ramping.
Conexant Confidential
07/31/14
008DSR00
58
CX20745 Data Sheet
Register Details
Table 123: SPKR_DRC_RELEASE_RATE_TH (0x77)
Bits
Name
Default
R/W Description
7:0
SPKR_DRC_RELEASE_RATE_TH
0x00
R/W Threshold for deciding whether to use slow release
(with RELEASE_UPDATE_STEP) or fast release
(with TRANSIENT_UPDATE_STEP).
Test Registers
Table 124: CODEC Test 0 (0x88)
Bits
Name
7
Digmic_freq
6:0
Reserved
Default
R/W
0x00
R/W
Default
R/W
Description
Set to 0x1 for the 1.5MHz digital microphone.
Reserved.
Table 125: CODEC Test 21 (0x9D)
Bits
Name
7:6
Pulse_1ms
0x00
5:0
R/W
Reserved
Description
Push button and rotary latching time
• 00b = 1ms
• 01b = 1ms
• 10b = 500μs
• 11b = Not valid
Reserved.
Table 126: CODEC Test 22 (0x9E)
Bits
Name
7:6
Reserved
5
Codec_test_regs22 [5]
4
Codec_test_regs22 [4]
3:0
Reserved
Default
R/W
Description
Reserved.
0x04
R/W
1 = Combo button enable.
1 = Combo jack enable.
Reserved.
Conexant Confidential
07/31/14
008DSR00
59
CX20745 Data Sheet
Register Details
Table 127: CODEC Test 23 (0x9F)
Bits
Name
7
Default
R/W
Description
Codec_test_regs23 [7]
R/W
Temp-Error enable to power-down class-D,
headphone, and interrupt generation.
6
Codec_test_regs23 [6]
R/W
Disable POR_5 error status and power-down class-D
on this status.
5
Codec_test_regs23 [5]
R/W
Disable short circuit error detect result and powerdown class-D on this status.
4:3
Reserved
2
Codec_test_regs23 [2]
1:0
Codec_test_regs23 [1:0]
0xA2
R
Reserved.
-
Threshold for the Temp-Error counter
• 0b = 99%
• 1b = 75%
R/W
Window selection for Temp-Error detection
• 00b = Bypass
• 01b = 100ms
• 10b = 150ms
• 11b = 200ms
R/W
Description
Table 128: Analog Test 4 (0xA8)
Bits
Name
Default
7:5
Reserved
Reserved.
4:3
testctrl4[4:3]
DAC channel selection for class-D
• 00 = L + R
• 01 = L + L
• 10 = R + R
• 11 = L + R
2:0
testctrl4[2:0]
0x00
R/W
Class-D 5V supply POR rise threshold control
• 000 = 4.22V
• 001 = 4.02V
• 010 = 3.85V
• 011 = 3.61V
• 100 = 3.4V
• 101 = 3.19V
• 110 = 2.99V
• 111 = 2.79V
Conexant Confidential
07/31/14
008DSR00
60
CX20745 Data Sheet
Register Details
Table 129: Analog Test 5 (0xA9)
Bits
Name
7:4
testctrl5[7:4]
Default
0xA0
3:0
R/W
R/W
Reserved
Description
Class-D power in 4Ω load
• 0000 = Reserved
• 0001 = Reserved
• 0010 = Reserved
• 0011 = Reserved
• 0100 = Reserved
• 0101 = 2W
• 0110 = 1.8W
• 0111 = 1.5W
• 1000 = 1.4W
• 1001 = 1.2W
• 1010 = 1W (default)
• 1011 = 0.8W
• 1100 = 0.6W
• 1101 = 0.5W
• 1110 = 0.4W
• 1111 = 0.25W
Reserved.
Table 130: Analog Test 6 (0xAA)
Bits
Name
7:6
testctrl6[7:6]
5:4
testctrl6[5:4]
3:0
Reserved
Default
R/W
Description
DAC channel selection for the headphone
• 00 = L + R
• 01 = L + L
• 10 = R + R
• 11 = L+R + L+R
0x00
R/W
DAC channel selection for the headphone
• 00 = L + R
• 01 = L + L
• 10 = R + R
• 11 = L+R + L+R (mono-mode summation)
Reserved.
Table 131: Analog Test 8 (0xAC)
Bits
Name
7:6
tstctrl8[7:6]
Default
0x00
5:0
Reserved
R/W
R/W
Description
Class-D 5V supply POR hysteresis control
• 00 = 740mV
• 01 = 530mV
• 1X = 320mV (set if class-D supply is 3V)
Reserved.
Conexant Confidential
07/31/14
008DSR00
61
CX20745 Data Sheet
Register Details
Table 132: Analog Test 13 (0xB1)
Bits
Name
Default
7:5
Reserved
Reserved.
4:0
testctrl13[4:0]
Class-D short-circuit current threshold control
• Threshold = (decimal code + 1)*100mA
• 00000 = 100mA
• 00001 = 200mA
• …
• 01111 = 1600mA (default)
• …
• 11110 = 3100mA
• 11111 = 3200mA
0x0F
R/W
R/W
Description
Table 133: Analog Test 14 (0xB2)
Bits
Name
7:6
testctrl14[7:6]
Default
0x19
R/W
Description
R/W
Adjust temperature sensor capacitor ratio
• 00b = 2:1
• 01b = 2.5:1
• 10b = 3:1
• 11b = 3.5:1
5:1
testctrl14[5:1]
Adjust temperature sensor current mirror ratio from
10:1 (code 0) to 41:1 (code 31).
0
testctrl14[0]
Power-on temperature sensor 1 = enable.
Read Only Registers
Table 134: Monitor ADC LSB (0xE1)
Bits
Name
Default
R/W
Description
7:0
adc_out_r [7:0]
0x00
R
Monitors the ADC LSB.
Table 135: Monitor ADC MSB (0xE2)
Bits
Name
Default
R/W
Description
7:0
adc_out_r [15:8]
0x00
R
Monitors the ADC MSB.
Table 136: Jack Sense Status and Bond Option (0xE3)
Bits
Name
Default
7:5
Reserved
Reserved.
4
Reserved
Reserved.
3
Jack Sense 4 Status
2
Jack Sense 3 Status
1
Jack Sense 2 Status
Status on the 2-bit.
0
Jack Sense 1 Status
Status on the 1-bit (LSB).
0x00
R/W
R
Description
Status on the 4-bit (MSB).
Status on the 3-bit.
Conexant Confidential
07/31/14
008DSR00
62
CX20745 Data Sheet
Register Details
Table 137: Class-D Protection Status (0xE4)
Bits
Name
R/W
Description
7:4
Reserved
Default
R
Reserved.
3
Sc_8_tr_or
R/W
Short circuit error status (write on clear).
2
Temp_error
R/W
Temp error status (write on clear).
1
Por_5
R/W
POR_5 error status (write on clear).
0
Class-D Error Sticky
R
Class-D error sticky status.
Default
R/W
Description
0x20
R
0x00
Table 138: Class-D Calibration Observe (0xE5)
Bits
Name
7
Reserved
6:0
Calibration_observe[6:0]
Reserved.
6-bit calibration value.
Table 139: HP A Offset Calibration Observe (0xE6)
Bits
Name
7
Hp_offcal_en
6:0
Hp_offcal_a [6:0]
Default
R/W
0x40
R
Description
Calibration enable status.
6-bit calibration value.
Table 140: HP B Offset Calibration Observe (0xE7)
Bits
Name
7
Hp_offcal_en
6:0
Hp_offcal_b [6:0]
Default
R/W
0x40
R
Description
Calibration enable status
6-bit calibration value.
Table 141: Memory BIST Status (0xE8)
Bits
Name
Default
7:4
Reserved
Reserved.
3
EQ RAM Fail
Indicates whether the EQ RAM failed the MBIST test.
2
DAC RAM Fail
0x00
R/W
Description
Indicates whether the DAC RAM failed the MBIST
test.
R
1
ADC RAM Fail
Indicates whether the ADC RAM failed the MBIST
test.
0
MBIST Test Done
Indicates whether the MBIST test was done.
Table 142: AGC Gain LSB Read Register (0xE9)
Bits
Name
Default
R/W
Description
7:0
Agc_gain_out_l
0x00
R
AGC gain LSB applied a read through a register.
Conexant Confidential
07/31/14
008DSR00
63
CX20745 Data Sheet
Register Details
Table 143: AGC Gain MSB Read Register (0xEA)
Bits
Name
Default
R/W
Description
7:0
Agc_gain_out_r
0x00
R
AGC gain MSB applied a read through a register.
Table 144: SPKR DRC Gain LSB Read Register (0xEB)
Bits
Name
Default
R/W
Description
7:0
Spkr_drc_gain_l
0x00
R
Speaker DRC gain LSB applied a read through a
register.
Table 145: SPKR DRC Gain MSB Read Register (0xEC)
Bits
Name
Default
R/W
Description
7:0
spkr_drc_gain_r
0x00
R
Speaker DRC gain MSB applied a read through a
register.
R/W
Description
Table 146: Micbias Detect Read Register (0xED)
Bits
Name
Default
7
Agc_compression_region
R
Indicates whether AGC is in the compression region.
6
Spkr_drc_compression
R
Indicates whether spkr_drc is in the compression
region.
5
Inc_vol_status
R/W
Rotary or push button status for incrementing the
volume—status is write on clear.
4
Dec_vol_status
R/W
Rotary or push button status for incrementing the
volume—status is write on clear.
3
Reserved
R
Reserved.
2
Micbias_down_up
R/W
Status on the volume down button, sticky on button
press, and write on clear.
1
Micbias_menu_button
R/W
Status on the menu button, sticky on button press,
and write on clear.
0
Micbias_volume_up
R/W
Status on the volume up button, sticky on button
press, and write on clear.
R/W
Description
0x40
GPIO Registers
Table 147: GPIO In Registers (0xF1)
Bits
Name
Default
7:4
Reserved
3
GPIO4_ In
2
GPIO3_ In
1
GPIO2_ In
GPIO 2 input status.
0
GPIO1_ In
GPIO 1 input status.
Reserved.
GPIO 4 input status.
0x00
R
GPIO 3 input status.
Conexant Confidential
07/31/14
008DSR00
64
CX20745 Data Sheet
Register Details
Table 148: GPIO Out Registers (0xF2)
Bits
Name
7:4
Reserved
Default
Reserved.
3
GPIO4_ Out
GPIO 4 output.
2
GPIO3_ Out
1
GPIO2_ Out
GPIO 2 output.
0
GPIO1_ Out
GPIO 1 output.
0x00
R/W
R/W
Description
GPIO 3 output.
Table 149: GPIO Direction Registers (0xF3)
Bits
Name
Default
7:4
Reserved
Reserved.
3
GPIO4_ OEN
GPIO 4 output enable (active low).
2
GPIO3_ OEN
1
GPIO2_ OEN
GPIO 2 output enable (active low).
0
GPIO1_ OEN
GPIO 1 output enable (active low).
0x00
R/W
R/W
Description
GPIO 3 output enable (active low).
Table 150: GPIO Control Registers (0xF4)
Bits
Name
7:6
SPI_CSN_DCCTL
5
GPIO_DCCTL
4:3
GPIO_DCCTL
2:0
GPIO_DRVCTL
Default
R/W
Description
R/W
SPI CSN pull-up control register.
R
GPIO pull-up control register.
R/W
GPIO pull-up control register.
R/W
GPIO drive control register.
Default
R/W
Description
0xFF
R/W
Default
R/W
0xC7
Table 151: I2S DATA Control (0xF5)
Bits
Name
7:3
Reserved
2:0
I2S_TX_DRVCTL
Reserved.
I2S Tx drive control register.
Table 152: DMIC Drive Control (0xF6)
Bits
Name
7:6
VREG_CTRL
R/W
Voltage regulator control.
5
Reserved
R
Reserved.
4:3
DMIC_DATA_TRIG
R/W
Digital microphone data drive control register.
2:0
DMIC_DRVCTL
R/W
DIGMIC CLK drive control register.
0x0D
Description
Table 153: Device ID LSB (0xFD)
Bits
Name
Default
R/W
Description
7:0
Device_ID_LSB
0x07
R
Device ID [7:0].
Conexant Confidential
07/31/14
008DSR00
65
CX20745 Data Sheet
Ordering Information
Table 154: Device ID MSB (0xFE)
Bits
Name
Default
R/W
Description
7:0
Device_ID_MSB
0x51
R
Device ID [15:8].
Default
R/W
Description
Table 155: Bond Option Read (0xFF)
Bits
Name
7:2
Reserved
1
Bond_opt
0
Bond_opt_r
Reserved.
-
R
Read bond option value.
Read bond opt read pad value.
Ordering Information
Table 156: Ordering Information
Device Part
Number
Part
Number
CX20745-11Z*
CX20745 Low-Power I2S CODEC 48-pin QFN, Industrial Temperature Range of –40°C to 85°C
Description
Package
Note: The CX20745 is lead-free (Pb-free) and RoHS compliant.
www.conexant.com
Headquarters: 1901 Main Street, Suite 300 Irvine, CA,92614
General Information: U.S. and Canada: 888-855-4562 | International: 1 + 949-483-3000
© 2014 Conexant Systems, Inc.
Information in this document is provided in connection with Conexant Systems, Inc. (“Conexant”) products. These materials are provided by
Conexant as a service to its customers and may be used for informational purposes only. Conexant assumes no responsibility for errors or
omissions in these materials. Conexant may make changes to this document at any time, without notice. Conexant advises all customers to
ensure that they have the latest version of this document and to verify, before placing orders, that information being relied on is current and
complete. Conexant makes no commitment to update the information and shall have no responsibility whatsoever for conflicts or
incompatibilities arising from future changes to its specifications and product descriptions.
No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in
Conexant’s Terms and Conditions of Sale for such products, Conexant assumes no liability whatsoever.
THESE MATERIALS ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, RELATING TO
SALE AND/OR USE OF CONEXANT PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A
PARTICULAR PURPOSE, CONSEQUENTIAL OR INCIDENTAL DAMAGES, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT,
COPYRIGHT, OR OTHER INTELLECTUAL PROPERTY RIGHT. CONEXANT FURTHER DOES NOT WARRANT THE ACCURACY OR
COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS, OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS.
CONEXANT SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS, WHICH MAY RESULT FROM THE USE OF THESE MATERIALS.
Conexant products are not intended for use in medical, lifesaving or life sustaining applications. Conexant customers using or selling Conexant
products for use in such applications do so at their own risk and agree to fully indemnify Conexant for any damages resulting from such
improper use or sale.
The following are trademarks of Conexant Systems, Inc.: Conexant® and the Conexant© symbol, SmartAudio, SmartJack, SmartCD, and
SmartDAA®. Product names or services listed in this publication are for identification purposes only, and may be trademarks of third parties.
Third-party brands and names are the property of their respective owners.
For additional disclaimer information, consult Conexant’s Legal Information posted at www.conexant.com which is incorporated by reference.
Reader Response: Conexant strives to produce quality documentation and welcomes your feedback. Please send comments and
suggestions to conexant.tech.pubs@conexant.com. For technical questions, contact your local Conexant sales office or field applications
engineer.
07/31/14
008DSR00
66