434 MHz Wireless Triple Axis Accelerometer
Reference Design
(ESTAR) Designer Reference Manual
ESTARRM
Rev. 0
02/2007
freescale.com
434 MHz Wireless Triple Axis Accelerometer
Reference Design
Designer Reference Manual
by: Petr Gargulák and Pavel Lajšner
Freescale Czech Systems Laboratories
Rožnov pod Radhoštěm, Czech Republic
To provide the most up-to-date information, the revision of our documents on the World Wide Web will be
the most current. Your printed copy may be an earlier revision. To verify you have the latest information
available, refer to:
http://www.freescale.com
The following revision history table summarizes changes contained in this document. For your
convenience, the page number designators have been linked to the appropriate location.
Revision History
Date
Revision
Level
February
2007
0.00
Description
First draft
Page
Number(s)
N/A
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
3
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
4
Freescale Semiconductor
Table of Contents
Chapter 1
Introduction
1-1
1-2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
MMA7260QT 3-Axes Accelerometer Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 2
434 MHz Wireless Triple Axis Accelerometer Reference Design Introduction
2.1
2.2
2.3
2.3.1
2.3.2
2.3.3
2.3.4
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
ESTAR Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Featured Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Triple Axis Accelerometer MMA7260QT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Microcontroller MC9S08QG8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
MC33696 ISM Bands Low Power Transceiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Microcontroller MCHC908JW32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Chapter 3
Sensor Board Description
3.1
3.2
3.2.1
3.2.2
3.3
3.3.1
3.3.2
3.3.3
3.3.4
3.4
3.4.1
3.4.2
3.4.3
3.4.4
3.4.5
3.4.6
3.4.7
3.4.8
3.4.9
3.4.10
3.4.11
3.5
3.6
3.7
Board Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A/D Conversion of XYZ Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ADC Module Init: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ADC Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Broadcast Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Normal Run Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Deep Sleep Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MC33696 Power Management Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ESTAR Sensor Board Hardware Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analog Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
g-select Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
g-sleep Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BDM (Background Debug Mode) Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Button Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MC33696 to MC9S08QG8 Microcontroller Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MC33696 RF Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clocking Options of MC9S08QG8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LED Indicator Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sensor Board Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sensor Board Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Memory Usage in MC9S08QG8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
17
18
18
19
20
21
21
22
22
22
22
22
22
23
23
24
25
25
25
26
27
28
28
434 MHz Wireless Triple Axis Accelerometer Reference Design , Rev. 0
Freescale Semiconductor
5
Chapter 4
USB Stick Board Description
4.1
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.2.6
4.2.7
4.2.8
4.2.9
4.3
4.4
4.5
USB Stick Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ESTAR USB Stick Board Hardware Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
USB Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MC33696 to MCHC908JW32 Microcontroller Interface . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oscillator and Clocking Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LED Indicators Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Button Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MON08 Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Optional Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
USB Stick Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
USB Stick Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Memory Usage in MCHC908JW32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
29
31
31
31
32
32
32
33
33
33
34
35
36
36
Chapter 5
Software Design
5.1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2
ECHO Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.1
Echo Driver Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3
ESTAR RF Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.1
Packet Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.1.1
ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.1.2
Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.1.3
Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.1.4
RX Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.1.5
Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.2
ESTAR Protocol Commands Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.2.1
CMD_TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.2.2
CMD_TRIAX_DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.2.3
CMD_ACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.2.4
CMD_CALIB_R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.2.5
CMD_CALIB_W . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.2.6
CMD_CALIB_ACK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.3
ESTAR RF Protocol Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.3.1
USB Stick RF State Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.3.2
Sensor Board RF State Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3.3.3
RF Communication Overview, Establish Connection Time Flow . . . . . . . . . . . . . . . . . .
5.4
STAR Protocol and ESTAR Extensions (over USB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.1
Communication Handshake ‘R’ (0x52) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.1.1
Extended Communication Handshake ‘r’ (0x72) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.2
Accelerometer Data Transfer ‘V’ (0x56) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.2.1
Extended Accelerometer Data Transfer ‘v’ (0x76) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.3
Calibration Data ‘K’ (0x4B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.4
Calibration Process ‘k’ (0x6B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
37
37
37
38
38
39
39
39
39
40
40
40
40
40
41
41
41
41
41
42
42
44
44
44
45
45
46
46
434 MHz Wireless Triple Axis Accelerometer Reference Design , Rev. 0
6
Freescale Semiconductor
5.4.4.1
Remaining STAR Demo Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5
Additional ESTAR Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5.1
g-Select Reading ‘G’ (0x47) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5.2
g-Select Setting ‘g’ (0x67) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5.3
Info ‘I’ (0x49) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5.4
ESTAR Help ‘H’(0x48), ‘h’(0x68) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5.5
Signal Strength (user friendly) ’s’(0x73) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5.6
Signal Strength (binary) ‘S’(0x53) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5.7
Read MC33696 Registers on USB Dongle ‘A’(0x41), ‘a’(0x61) . . . . . . . . . . . . . . . . . . .
5.4.5.8
Temperature and Battery ‘T’(0x54), ‘t’(0x74) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5.9
Working Mode ‘M’(0x4D), ‘m’(0x6D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5.10
Show Calibration Data ‘q’(0x71) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5.11
Read g-Select ‘N’(0x4E),’n’(0x6E) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.5.12
Debug On ‘U’ (0x55) and Debug Off ‘u’ (0x75) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.6
Further Debug and Test Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4.6.1
Semi-Automatic Self-Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5
Bootloader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.1
Bootloading Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.2
Dualboot Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5.2.1
Dualboot Applications Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
47
47
47
47
47
48
48
48
49
49
49
50
50
50
51
51
51
52
54
55
Chapter 6
Application Setup
6.1
6.1.1
6.1.2
ESTAR Installation Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
USB stick Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
AN2295 Bootloader Drivers Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Appendix A
References
434 MHz Wireless Triple Axis Accelerometer Reference Design , Rev. 0
Freescale Semiconductor
7
434 MHz Wireless Triple Axis Accelerometer Reference Design , Rev. 0
8
Freescale Semiconductor
Chapter 1
Introduction
1.1 Introduction
This paper describes the design of a 434 MHz Wireless Triple Axis Accelerometer Reference Design
(ESTAR), a wireless demonstration of the 3-axes accelerometer MMA7260QT sensors from Freescale.
The reference design will enable you to see how Freescale's accelerometers can add additional
functionality to applications in various industries. The accelerometer measurements can be grouped into
6 sensing functions - Fall, Tilt, Motion, Positioning, Shock and Vibration - for multifunctional applications.
The RD3162MMA7260Q development tool offers robust wireless communication using the easy-to-use
433.92 MHz frequency MC33696 transceiver.
1.2 MMA7260QT 3-Axes Accelerometer Sensor
The MMA7260QT low cost capacitive micromachined accelerometer features signal conditioning, a
1-pole low pass filter and temperature compensation, and g-Select, which allows a selection from 4
sensitivities. Zero-g offset full scale span and filter cut-offs are factory set and require no external devices.
This device includes a sleep mode making it ideal for handheld battery powered electronics.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
9
Introduction
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
10
Freescale Semiconductor
Chapter 2
434 MHz Wireless Triple Axis Accelerometer Reference
Design Introduction
2.1 Introduction
The 434 MHz Wireless Triple Axis Accelerometer Reference Design (ESTAR) has been designed as a
wireless complement to the previous STAR (Sensing Triple Axis Reference design) RD3112MMA7260Q
demo. A 433.92 MHz radio-frequency (RF) link based on the low-cost MC33696 family is used for
connection from the sensor to the PC, allowing the visualization of key accelerometer applications
Figure 2-1 ESTAR Demo Overview
The demo consists of the two boards:
• Sensor Board (or remote board) containing the MMA7260QT 3-axes accelerometer, S08 family
MC9S08QG8 8-bit microcontroller and the 433.92 MHz RF chip MC33696 for wireless
communication.
• USB stick, again with the MC33696 RF front-end, and the HC08 family MCHC908JW32 for the
USB communication.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
11
ESTAR Features
MC33696
MC33696
S08QG8
HC908JW32
MMA7260QT
Figure 2-2 ESTAR Block Diagram
2.2 ESTAR Features
Features of the ESTAR include:
• Sensing of acceleration in 3 axes across four ranges (0-1.5 g, 2 g, 4 g and 6 g)
• Wireless communication of sensor data through 433.92 MHz
• Typical wireless range is 20 m, two walls or one floor
• Data rate is 19.2 kb/s, half duplex
• USB communication of the receiver part
– Virtual serial port class - interface for GUI and terminal
– HID class - mouse for windows
• 2 push buttons provide:
– wake-up function
– user functions, mouse buttons for HID class
• Current consumption:
– in normal run mode: 4.5 - 5.5 mA depending on battery voltage
– in sleep mode: less than 4.5 µA
• Support low power mode for all parts
• Sensor Board powered by a coin-sized CR2032 battery
• 8-bit/16-bit working modes
2.3 Featured Products
This demo consists of several Freescale products whose main features are listed below.
2.3.1 Triple Axis Accelerometer MMA7260QT
The ESTAR board is a demonstration tool for the MMA7260QT, a 3-axes low-g accelerometer. The
MMA7260QT has many unique features that make it an ideal solution for many consumer applications,
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
12
Freescale Semiconductor
Featured Products
such as freefall protection for laptops and MP3 players, tilt detection for e-compass compensation and
mobile phone scrolling, motion detection for handheld games and game controllers, position sensing for
g-mice, shock detection for warranty monitors, and vibration for out of balance detection.
Features such as low power, low current, and a sleep mode with a quick turn on time, allow the battery
life to be extended in end use applications. The 3-axes sensing in a small QFN package requires only a
6 mm x 6 mm board space, with a profile of 1.45 mm, allowing for easy integration into many small
handheld electronics.
There are several other derivatives of the MMA7260QT, including:
• MMA7261QT with a selectable 2.5 g to 10 g range
• MMA6270QT is an XY dual axes accelerometer
• MMA6280QT is an XZ dual axes accelerometer
All members of this sensor family are footprint (QFN package) compatible which simplifies evaluation and
design of the target application.
2.3.2 Microcontroller MC9S08QG8
The MC9S08QG8 is a highly integrated member of Freescale’s 8-bit family of microcontrollers based on
the high-performance, low-power consumption HCS08 core. Integrating features normally found in larger,
more expensive components, the MC9S08QG8 MCU includes a background debugging system and
on-chip in-circuit emulation (ICE) with real-time bus capture, providing a single-wire debugging and
emulation interface. It also features a programmable 16-bit timer/pulse-width modulation (PWM) module
(TPM), that is one of the most flexible and cost-effective of its kind.
The compact, tightly integrated MC9S08QG8 delivers a versatile combination from a wealth of Freescale
peripherals and the advanced features of the HCS08 core, including extended battery life with a
maximum performance down to 1.8 V, industry-leading Flash and innovative development support. The
MC9S08QG8 is an excellent solution for power and size-sensitive applications, such as wireless
communications and handheld devices, small appliances, Simple Media Access Controller
(SMAC)-based applications and toys.
MC9S08QG8 Features
• Up to 20 MHz operating frequencies at >2.1 volts, and 16 MHz at <2.1 volts
• 8 K Flash and 512 bytes RAM
• Support for up to 32 interrupt/reset sources
• 8-bit modulo timer module with an 8-bit prescaler
• Enhanced 8-channel, 10-bit Analog-to-Digital Converter (ADC)
• Analog comparator module
• Three communication interfaces: SCI, SPI and IIC
2.3.3 MC33696 ISM Bands Low Power Transceiver
The MC33696 is a highly integrated transceiver designed for low-voltage applications. It includes a programmable PLL for multi-channel applications, an RSSI circuit, a strobe oscillator that periodically wakes
up the receiver while a data manager checks the content of incoming messages. A configuration switching feature allows automatic configuration changes between two programmable settings with no need for
an MCU.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
13
Featured Products
MC33696 Features
• 304 MHz, 315 MHz, 426 MHz, 434 MHz, 868 MHz, and 915 MHz ISM bands
• OOK and FSK transmission and reception
• 20 kbps maximum data rate using Manchester coding
• 2.1 V to 3.6 V or 5 V supply voltage
• Programmable via SPI
• 6-kHz PLL frequency step
• Current consumption:
– 13.5 mA in TX mode
– 9.2 mA in RX mode
– Less then 1 mA in RX mode with strobe ratio = 1/10
– 250 nA standby and 25 µA off currents
• Configuration switching — allows fast switching of two register banks
• Receiver includes:
– Sensitivity of -104 dBm
– Digital and analog RSSI (Received Signal Strength Indicator)
– Automatic walk-up function (strobe oscillator)
– Embedded data processor with programmable word recognition
– Image cancelling mixer
– 380-kHz IF filter bandwidth
– Fast walk-up time
• Transmitter includes:
– 7 dBm output power
– Programmable output power
– FSK done by PLL programming
2.3.4 Microcontroller MCHC908JW32
The MCHC908JW32 is a member of the low-cost, high-performance M68HC08 Family of 8-bit
microcontroller units (MCU’s). All MCU’s in the family use the enhanced M68HC08 central processor unit
(CPU08) and are available in a variety of modules, memory sizes and types, and package types.
MCHC908JW32 Features
• Maximum internal bus frequency: 8 MHz at 3.5 - 5 V operating voltage
• Oscillators:
– 4-MHz crystal oscillator clock input with a 32-MHz internal phase-lock loop
– Internal 88-kHz RC oscillator for timebase wakeup
• 32,768 bytes user program FLASH memory with security feature
• 1,024 bytes of on-chip RAM
• 29 general-purpose Input/Output (I/O) ports:
• 8 keyboard interrupt with internal pull-up
– 3 pins with direct LED drive
– 2 pins with 10 mA current drive for PS/2 connection
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
14
Freescale Semiconductor
Featured Products
•
•
•
•
•
16-bit, 2-channel Timer Interface Module (TIM) with selectable input capture, output compare,
PWM capability on each channel, and external clock input option
Timebase module
PS/2 clock generator module
Serial Peripheral Interface module (SPI)
Universal Serial Bus (USB) 2.0 Full Speed functions:
– 12 Mbps data rate
– Endpoint 0 with an 8-byte transmit buffer and an 8-byte receive buffer
– 64 bytes endpoint buffer to share amongst endpoints 1 - 4
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
15
Featured Products
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
16
Freescale Semiconductor
Chapter 3
Sensor Board Description
3.1 Board Overview
The Sensor Board provides measurement of the accelerations in 3 axes and transmits the measured
values through 433.92 MHz ISM band wireless communication. Also, two on-board push buttons enable
the sending of additional application commands.
The Sensor Board accommodates:
• MMA7260QT - 3 axes accelerometer (4 ranges: 1.5g, 2g, 4g, 6g)
• MC9S08QG8 - HCS08 microprocessor
• MC33696 - RF low power transceiver for ISM bands
The Sensor Board utilizes a small footprint size dual-layer Printed Circuit Board (PCB) containing all the
necessary circuitry for MMA7260QT accelerometer sensing and transferring data over a radio frequency
(RF). The board is powered by a Lithium coin-sized CR2032 battery.
MC33696
B1 and B2 Buttons
MMA7260QT
LED
Q1 Crystal
CR2032 Battery Holder
and MC9S08QG8
on opposite side
433.92 MHz Loop Antenna
Figure 3-1 Sensor Board Overview
The block diagram of the board is shown in Figure 3-2.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
17
Board Overview
SPI
MC9S08QG8
MCU
SEB
CONFB
MC33696
433.92 MHz RF
X Y Z sleep g-select
CR2032
Lithium Battery
Matching
Circuit
Antenna
MMA7260Q
Accelerometer
Figure 3-2 Sensor Board Block Diagram
The main task of the Sensor board is to:
• periodically wake-up from power saving mode
• measure all three XYZ acceleration values from the sensor
• compose a data frame using simple ESTAR RF Protocol
• use ECHO Driver to send this data frame over the RF link
• wait for an acknowledgment from the other end (here, the USB stick)
• go to sleep
This basic loop repeats roughly 16 times per second providing nearly a real-time response from the
sensor. The Sensor Board can be woken up using any push button on the board. Switch off of the Sensor
Board is done automatically after dead time from the last push of a button.
Figure 3-3 shows in more detail how different software and hardware modules co-operate with each
other.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
18
Freescale Semiconductor
A/D Conversion of XYZ Levels
MC9S08QG8
software
calibration data
ESTAR RF protocol handler
Sensor data
ECHO driver
Analog-to-Digital converter
(ADC) module
MMA7260Q
sleep
g-select
GPIO
TIM
SPI module
SEB
CONFB
MC33696
Figure 3-3 ESTAR Sensor Board Software Overview
For the Sensor board operation, several of the MC9S08QG8’s hardware modules are used:
• Analog to Digital Converter (ADC) - measurement of accelerometer data, battery voltage and
temperature
• Synchronous Peripheral Interface (SPI) - communication with the MC33696 (configuration and
receive)
• Time/Pulse-Width Modulator (TIM) - generation of Manchester code for outgoing messages
• General Purpose Input/Output (GPIO) - control of the MC33696, buttons, LED and g-select signals
3.2 A/D Conversion of XYZ Levels
The 3-axes accelerometer sensor MMA7260QT provides three separate analog levels for the X, Y and Z
axes. These outputs are ratiometric which means that the output offset voltage and sensitivity will scale
linearly with applied supply voltage. This is a key feature when interfacing to a microcontroller with A/D
converter reference levels tied to a power supply, because it provides system level cancellation of supply
induced errors in the analog to digital conversion process.
During the analog-to-digital conversion in the microcontroller, 10-bit or 8-bit resolution is used according
to active mode of ESTAR. MC9S08QG8 A/D channels 1, 2 and 3 are connected to X (channel 3), Y
(channel 2) and Z (channel 1) outputs of the MMA7260QT. The microcontroller’s APCTL1 register enables
these ADC channels for pin I/O control by the ADC module.
The ADCCFG register controls the selected mode of operation, clock source, clock divide, and
configuration for low power or long sample time.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
19
A/D Conversion of XYZ Levels
3.2.1 ADC Module Init:
APCTL1
Enable analog
ADCSC1
ADCSC2
ADCCFG
= (APCTL1_ADPC1_MASK | APCTL1_ADPC2_MASK | APCTL1_ADPC3_MASK);
inputs */
= 0x1f;
/* Initialization ADC */
= 0x00;
/* Initialization ADC */
= ADCCFG08;
/*
Where ADCCFG08 is:
#define ADCCFG08
high speed */
#define ADCCFG16
high speed */
0b01100000
/* set prescale to 8, ADICLK=BUS, 8-bit,
0b01111000
/* set prescale to 8, ADICLK=BUS, 10-bit,
Actual ADC measurements are done in the main software loop. There is a macro (called POWSUM) that
allows configuration of measurement to take several measurements of each channel during one loop. E.g.
changing POWSUM to 3, 2^3 = 8, each channel will be measured 8 times, with POWSUM 6, each channel
is measured 64 times. By default, POWSUM is 4, for 16 measurements of each channel. Before result
values are provided, the accumulated values are left justified to the 16-bit range and inverted where
necessary (may be required depending on the physical MMA7260QT device orientation relative to the
Earth gravity).
Raw (i.e. not calibrated) values are actually sent, the calibration and calculation of an exact g value is
done internally in the PC software.
3.2.2 ADC Measurement
The following routine is used for accelerometer measurement:
byte i;
unsigned int xx,yy,zz,tt,bb;
ADCCFG = (estarmode_key == MODE08)? ADCCFG08 : ADCCFG16;
xx=yy=zz=tt=bb=0;
for (i=0;i< (1 << POWSUM);i++)
{
ADCSC1 = ADC_AXIS_X;
//read X channel
while(!ADCSC1_COCO);
xx+= ADCR;
ADCSC1 = ADC_AXIS_Y;
while(!ADCSC1_COCO);
yy+= ADCR;
//read Y channel
ADCSC1 = ADC_AXIS_Z;
while(!ADCSC1_COCO);
zz+= ADCR;
}
//read Z channel
G_SLEEP = 0;
/* Send accelerometr to sleep mode */
if(estarmode_key == MODE16)
// switch between 8 and 16 bits mode
{
// 16 bits mode
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
20
Freescale Semiconductor
Power Management
xx = (xx << (16-(10+POWSUM)));
echoTransmitBuffer[7] = (unsigned char)
echoTransmitBuffer[8] = (unsigned char)
yy = (yy << (16-(10+POWSUM)));
echoTransmitBuffer[9] = (unsigned char)
echoTransmitBuffer[10] = (unsigned char)
zz = (zz << (16-(10+POWSUM)));
echoTransmitBuffer[11] = (unsigned char)
echoTransmitBuffer[12] = (unsigned char)
}
else
{
// 8 bits
echoTransmitBuffer[7] = (unsigned char)
echoTransmitBuffer[8] = (unsigned char)
echoTransmitBuffer[9] = (unsigned char)
}
((xx & 0xff00)>>8);// Axis X high
(xx & 0x00ff);// data: Axis X low
((yy & 0xff00)>>8);// Axis Y high
(yy & 0x00ff);// data: Axis Y low
((zz & 0xff00)>>8);// Axis Z high
(zz & 0x00ff);// data: Axis Z low
mode
(xx >> POWSUM);// data: Axis X
(yy >> POWSUM);// data: Axis Y
(zz >> POWSUM);// data: Axis Z
3.3 Power Management
A CR2032 Lithium battery provides a fairly limited charge for such a realtime-like demo that demands
frequent transmissions. Some sort of power management has to be implemented in order to keep the
current consumption at a reasonable level.
Typically, current consumptions of the Sensor board components are as follows:
• 433.92 MHz transceiver MC33696
– in Stand-by mode, 250 nA
– in Transmit mode, 13.5 mA
– in Receive mode, 9.2 mA
•
8-bit microcontroller MC9S08QG8
– in Stop mode, 750 nA
– in Wait mode, 1 mA
– in Run mode, 3.5 mA
•
low-g triaxial sensor MMA7260QT
– in Sleep mode, 3 µA
– in Normal mode, 500 µA
It is obvious that in a battery operated application care must be taken to ensure the lowest possible current
consumption, especially when the maximum current (provided by the battery) is somehow limited. A
CR2032 Lithium battery cannot provide current in the range of 20 mA for long periods of time. To alleviate
high current surges, an additional large capacitor has been designed - see Section 3.4.10.
For decreasing current consumption the ESTAR Sensor Board works in three different modes:
• Broadcast Mode - ESTAR Sensor Board looking for a USB stick
• Normal Run Mode - Normal ESTAR Sensor Board work
• Deep Sleep Mode - all components on the Sensor Board are sleep/stop/standby mode
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
21
Power Management
Table 3-1 ESTAR Current Consumption
ESTAR current consumption
Battery voltage [V]
3
2.7
2.4
Broadcast [mA]
7.3
7.3
7.3
Normal run 8-bit [mA]
4.52
4.45
4.3
Normal run 16-bit [mA]
5.22
5.05
4.85
Deep sleep [uA]
4.3
3.7
3
2.1
6.5
3.89
4.34
2.6
ESTAR Current Consumption
8
6
5
4
Current [mA] [ uA]
7
3
2
1
0
3
2.8
Broadcast [mA]
2.6
Battery voltage [V]
Normal run 8-bit [mA]
2.4
2.2
Normal run 16-bit [mA]
2
Deep sleep [uA]
Figure 3-4 ESTAR Sensor Board Current Consumption
3.3.1 Broadcast Mode
When a battery is connected to the Sensor Board, or after each wake-up from Deep Sleep Mode, the
ESTAR Sensor Board goes into Broadcast Mode. In this session, the Sensor Board is periodically looking
for a USB stick via the 5.3.2.1 CMD_TEST command with a ~60ms delay. When the Sensor Board
doesn’t succeed after 30 tests (a time of about 2.1 s), then it moves on to the Deep Sleep Mode again.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
22
Freescale Semiconductor
Power Management
3.3.2 Normal Run Mode
For transmission and reception operations using the MC33696, a specific scheme has been used to
ensure the battery is not depleted or overloaded. Targeting a 16 samples per second (~60 ms period)
transmission rate, the following scheme for one transmission/sleep cycle is used for the data transfer:
MC9S08QG8:
Wait
Wait
Run
Wait
Wait/Run
Wait
MC33696:
Standby
TX
Standby
RX
Standby
MMA7260QT:
Sleep
Normal
Sensor
stabilizes
wake-up
Sensor
being
measured
Sleep
time
data
transmitted
optional
receive
window
NOT TO SCALE
Figure 3-5 Normal Run Mode Details
As shown on the previous diagram, all parts of the Sensor Board remain most of the time in
Wait/Sleep/Standby modes, in which the total current consumption is below 500 µA.
During each loop, once the data has been acquired from the sensor, transmission over the MC33696
transceiver is initiated. The current consumption of the transmitter is ~17 mA at that time, but only for a
short period of time (typically ~7 ms).
In order to keep the sensor board informed on the status of connection (for example, if the data-receiving
side - USB stick - is out of range, disconnected, etc.), the reception has to be turned on after the data has
been transmitted. This is not really required within each loop cycle. In the actual implementation only on
every 8th loop is there a check to see if the Sensor Board receives any acknowledgment from the last 8
transmissions. If not, then the software significantly reduces the dead time to Deep Sleep Mode. The dead
time is actually set to 2 minutes and starts from each push on a board button. More details can be found
in the 5.3 ESTAR RF Protocol description.
For the receive window, the MC33696 Strobe oscillator is used. This option mainly reduces the current
consumption.
3.3.3 Deep Sleep Mode
When the dead counter in Broadcast Mode or Normal Run Mode overflows, the software puts the
MC33696 into the standby mode, MMA7260QT to the sleep mode and the MC9S08QG8 into the stop3
mode. Before the MCU is put into stop3 mode, all pins are set as inputs and the pull-ups internal resistors
are enabled (except those pins routed to the MC33696, because digital pins on the MC33696 are in
logical zero during standby mode).
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
23
ESTAR Sensor Board Hardware Overview
3.3.4 MC33696 Power Management Features
MC33696 provides two power saving modes:
• mode1 - can be used in receive mode. When activated, the strobe oscillator periodically wakes up
the MC33696 from standby. This is a power efficient and accurately timed way of waking-up the
application after a specified time. After wake up, the internal counter can put the chip into standby
again after ON time passes. If, during ON time, the chip receives any message preamble with the
right ID, it receives the complete message then goes into standby again. This feature is fully utilized
within the MC33696. The microcontroller only sets the required registers in the MC33696.
• mode 2 - standby is used for switching off the device and mostly for power saving.
3.4 ESTAR Sensor Board Hardware Overview
This section describes the Sensor board in terms of the hardware design. The MC9S08QG8
microcontroller drives both the MMA7260QT sensor and the MC33696 RF transceiver. The structure is
evident from Figure 3-2, Sensor Board Block Diagram. In the following sections, the details of the H/W
structure are described.
3.4.1 Analog Connections
The MMA7260QT sensor is directly connected to the AD0, AD1 and AD2 inputs of the analog-to-digital
converter. The software filtering, also described in Section 3.2, substitutes for external RC filters.
3.4.2 g-select Connections
The G-sel1 and G-sel2 MMA7260QT sensor input pins (used for selection of the acceleration range) are
connected to pins PTB0 and PTB7 of the microcontroller. The range can be controlled by software.
If the MMA7260QT is in sleep mode then PTB0 and PTB7 (or their alternate SCI functionality of RxD1
and TxD1, or KBI or AD inputs) may be used. These signals are also routed to the BDM connector - pins
3 and 5.
Pin PTB0 is also used for LED control.
3.4.3 g-sleep Connection
SLEEP is connected to the microcontroller PTA4 pin sharing its alternate RESET function when BDM
communication is active.
3.4.4 BDM (Background Debug Mode) Connections
A J2 connector is a non-standard footprint primarily intended for in-factory programming and testing via
“spring-needle” type of connections. The J2 connector carries all standard signals for Background Debug
Mode communication; therefore, if required, one may solder wires and a standard 2x3 pin 2.54 mm
(100 mil) pitch header for regular BDM re-programming. The pin numbering is shown in Figure 3-6.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
24
Freescale Semiconductor
ESTAR Sensor Board Hardware Overview
1
2
4
6
3
5
Figure 3-6 BDM Connector Layout
3.4.5 Button Connections
Two buttons (S1 and S2) are connected directly to pins PTA5 and PTB1. Both have internal pull-up
resistors. The first button is connected to IRQ and the second to the Keyboard interrupt module, therefore
allowing a direct microcontroller wake-up from the Stop modes.
3.4.6 MC33696 to MC9S08QG8 Microcontroller Interface
In order to fit all the necessary circuitry onto a 16-pin microcontroller, the full recommended MC33696
interface has had to be reduced. The full MC33696 interface includes the following connections:
• 3-wire Synchronous Peripheral Interface (SPI) connection (MISO, MOSI, SPICLK)
• Data - output pin from TIM module
• Serial interface enable (SEB)
• Configuration mode (CONFB)
• Receive Strength Signal Indicator Control input (RSSIC)
• RSSI analog output (RSSIOUT)
• Data Clock output to microcontroller (DATACLK)
• Low Voltage Detect output (LVD)
• Strobe oscillator external control input (STROBE)
On the ESTAR Sensor Board, the following signals are not used (reason, compensation):
• RSSIC - saving pins on the MCU, this signal is connected permanently to VCC, so RSSI is not
triggered and the measured value of RSSI is floating.
• RSSIOUT - saving pins on the MCU, the RSSI value is read by the digital interface.
• DATACLK - saving pins on the MCU, used time is generated from the TIM module in the MCU.
• LVD - saving pins on the MCU, this function is not used
• STROBE - saving pins on the MCU, the ESTAR Sensor Board permanently uses the strobe
oscillator in receive mode.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
25
ESTAR Sensor Board Hardware Overview
SPI, DATA, SEB and CONFB are vital for the communication and configuration of the MC33696. SPI is
connected to the MC9S08QG8 SPI module (pins PTB4/MISO1, PTB3/MOSI1 and PTB2/SPSCK1).
DATA is connected to both the microcontroller pins PTA0/TPM1CH0 and PTB4/MISO1.
• in transmit mode - pin PTB3/MOSI1 is in high-Z state and pin PTA0/TPM1CH0 generates the
transmitted message.
• in receive and configuration mode - pin PTA0/TPM1CH0 is in high-Z state and pin PTB3/MOSI1 is
used for the SPI module
Serial Interface Enable (SEB) allows individual selection in a multiple device system, where all devices
are connected via the same bus. When SEB is set high, pins SCLK, MOSI, and MISO are set to high
impedance.
Configuration Mode (CONFB) signal is used to control configuration mode. On a CONFB falling edge,
the on chip SPI is set to slave mode and prepared to receive a command byte via the SPI from the MCU.
This pin has the highest priority on chip.
RSSI Control Input (RSSIC) signal controls receive strength signal indicator in sample mode.
RSSI Analog Output (RSSIOUT) provides an analog value of receive strength signal.
Data Clock Output (DATACLK) can be used for the external clock input timer module to simplify
generating Manchestr code.
Low Voltage Detect Output (LVD) indicates a lower Vdd voltage than the internal reference threshold of 1.8 V.
Strobe Oscillator Control Pin (STROBE) can be used as an external control pin for active mode in
receive, or to connect an external capacitor for the strobe oscillator.
3.4.7 MC33696 RF Interface
The RF interface (antennas) was designed with cost and board size in mind. Therefore, a PCB layout
antenna is used. Several PCB antenna designs are available for the 433.92 MHz band (F-antenna, dipole,
loop). Because of the space limitation on the PCB a loop antenna has been selected.
The MC33696 transceiver is designed with separated RFIN (receive) and RFOUT (transmit) paths. To
combine both signal paths, a reference layout from a datasheet is used. On the Sensor Board the
“smile”-like antenna layout is used, because of the space restriction on the ring board design.
Figure 3-7 ESTAR Sensor Board Antenna Layout
The matching is provided by coil L2 and capacitors C17, C18. For the type and size of the components,
refer to the BOM
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
26
Freescale Semiconductor
ESTAR Sensor Board Hardware Overview
3.4.8 Clocking Options of MC9S08QG8
An MC9S08QG8 internal oscillator (ICG) is used as the main clock source for the microcontroller. The
protocol related timing is derived from the MCU bus clock. When the microcontroller itself is clocked from
an internal oscillator, the oscillator pins can be used as GPIO. This is highly beneficial to the limited pin
count microcontroller.
3.4.9 LED Indicator Connection
The LED diode signal is shared with g-select1/RXD. The reason is a limited pin count on the
microcontroller.
3.4.10 Power Supply
The Sensor board is powered by a Lithium coin-sized battery. The choice was the popular CR2032.
A surface mounted SMTU series battery holder is placed on the underside of the PCB. The SMTU series
holders provide (by mechanical construction) battery reverse protection, so no additional circuitry is
required.
A large tantalum capacitor (C1, 470 µF/4 V) improves the response of the power supply to current peaks
caused by reception or transmission. Coin-sized Lithium CR2032 batteries are targeted at a maximum
continuous discharge current in the range of 3 mA. Such a large capacitor helps to supply enough current
to the MC33696 during a receive/transmit without significant Vdd voltage drops.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
27
3.3pF
C18
C16
1nF
GND
L2
100nH
GND
100pF
C10
C11
1nF
C9
100pF
8
7
6
5
4
3
2
1
GNDPA2
RFOUT
GNDPA1
VCC2VCO
GNDLNA
RFIN
VCC2RF
RSSIOUT
GND
C4
6.8pF
1nF
Q1
C5
NX3225GA - 24Mhz
1
2
GND
C15
1nF
MC33696
ECHO+
100nF
GND
100nF
C8
R3
470K - 1%
VDD
GNDDIG
RSSIC
SPICLK
MOSI
MISO
CONFB
22
21
20
VDD
GND
18
17
19
SEB
24
23
TO MCU
only input
only output
GND
BDM
VDD
J2
BDM
+
BUTTON2/TXD
G_SEL1/RxD
SLEEP/BDM
BUTTON1/RES
LED
C1
GND BATT1 470uF/4V
Battery/Renata CR2032
SOURCE
Figure 3-8 Sensor Board Schematic
100nF
C6 C7
MISO
MOSI
SCLK
SEB
DATACLK
GND
VDD
GND
GND
C14
100nF
CONFB
XTALOUT
10
U3
C13
1nF - 5%
C12
100pF
VDD
G_SEL2
CONFB
SEB
MISO
VCCINOUT
11
32
BUTTON1/RES
SLEEP/BDM
VCC2OUT
12
VDD
L1
39nH
1
2
3
4
5
6
7
8
VCCDIG
13
MC33696 + RF
MC9S08QG8CDTE
C driver ECHO.C / H request signals RSSIC, CONFB, SEB
PTA0/KBI0/AD0/TPM1CH0/ACMP1+ PTA5/RESET/IRQ/TCLK
PTA1/KBI1/AD1/ACMP1PTA4/BKGD/MS/ACMP1O
PTA2/KBI2/AD2/SDA1
Vdd
PTA3/KBI3/AD3/SCL1
Vss
PTB0/KBI4/AD4/RxD1
PTB7/SCL1/EXTAL
PTB1/KBI5/AD5/TxD1
PTB6/SDA1/XTAL
PTB2/KBI6/AD6/SPSCK1
PTB5/TPM1CH1/SS1
PTB3/KBI7/AD7/MOSI1
PTB4/MISO1
VCCDIG2
14
Timer chanel output
MOSI
16
ADC_X 15
ADC_Y 14
ADC_Z 13
G_SEL1/RxD
12
LED1
BUTTON2/TXD 11
SPICLK
10
MOSI
9
U2
3
15
MCU
4
31
RBGAP
GND
XTALIN
9
SWITCH
30
VCC2IN
29
GNDSUBD
28
STROBE
27
LVD
26
VCCIN
25
GNDIO
GND
16
2
4
6
1
3
5
GND
GND
D1
LED
470R
R1
LED1
C2
10nF
VDD
C3
10nF
SLEEP/BDM
G_SEL2
G_SEL1/RxD
12
2
1
SLEEP
g-Sel2
g-Sel1
U1
ADC_Z
BUTTON1/RES
GND
BUTTON2/TXD
ADC_Y
13
GND
SPICLK
MOSI
MISO
1
1
1
1
ADC_X
14
15
GND
SPICLK
MOSI
MISO
TEST POINTS
Alps SKRP
S1
Alps SKRP
S2
BUTTONS
GND
Z
Y
X
MMA7260QT
VDD
ACCELEROMETER
3
VDD
EGND1
EGND2
EGND3
EGND4
17
18
19
20
VSS
4
1
2
3
4
3
4
28
1
2
3.4.11 Sensor Board Schematic
ESTAR Sensor Board Hardware Overview
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
Bill of Materials
3.5 Bill of Materials
Table 3-2 Sensor Board Bill of Materials
Item
Quantity
Reference
Part
Manufacturer
Manufacturer Order Code
1
1
BATT1
battery holder
CR2032
Renata
SMTU 2032-1
2
1
C1
100uF/6.3V
AVX
TAJB107K006R
3
2
C2,C3
10nF
AVX
06035C103KAZ2A
4
1
C4
6.8pF
PHYCOMP
223886715688
5
4
C5,C11,C15,C16
1nF
AVX
06035C102KAT2A
6
1
C13
1nF - 5%
AVX
6
4
C6,C7,C8,C14
100nF
AVX
06033G104ZAT2A
7
3
C9,C10,C12
100pF
AVX
06035A101JAT2A
9
1
C18
3.3pF
AVX
06032U3R3BAT2A
8
1
D1
KP-1608SEC
Kingbright
KP-1608SEC
9
1
J2
BDM + serial
N/A
10
1
L1
39nH
TDK
MLG1608B39NJT
11
1
L2
100nH
TDK
MLG1608B10JT
12
1
Q1
24MHz NX3225GA
NDK
NX3225GA 24MHz S1-4085-8050-8
13
1
R1
470R
resistor 0603 package
any available
15
1
R3
470k - 1%
resistor 0603 package
any available
16
2
S1,S2
switch SKRP
Alps
SKRPADE010
(or SKRPACE010 or SKRPABE010)
18
1
U1
MMA7260QT
Freescale
MMA7260QT
(MMA7260QR2 for tape and reel)
19
1
U2
MC9S08QG8CDTE
Freescale
MC9S08QG8CDTE
20
1
U3
MC33696
Freescale
MC33696FJE/R2
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
29
Sensor Board Layout
3.6 Sensor Board Layout
Copper
Silk Screen
Solder Mask
φ34.5mm
Top
Bottom
34.5mm=1.36in
Figure 3-9 Sensor Board PCB Layout (1:1)
3.7 Memory Usage in MC9S08QG8
Table 3-3 Memory Usage in MC9S08QG8
Memory Usage in MC9S08QG8
Type
Hexadecimal Value
DECimal Value
READ_ONLY (R)
1422
5154
READ_WRITE (R/W)
AC
172
Available Memory in MC9S08QG8
READ_ONLY (R)
2000
8192
READ_WRITE (R/W)
200
512
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
30
Freescale Semiconductor
Chapter 4
USB Stick Board Description
4.1 USB Stick Overview
The USB Stick provides a communication bridge between the Sensor Board connection over RF and the
PC application via the USB interface. On board there are also three indication LED’s and one push button.
The USB Stick accommodates:
• MCHC908JW32 - HC08 microprocessor with USB module
• MC33696 - RF low power transceiver for ISM bands
The USB Stick board utilizes the small footprint as the Sensor Board, being also a dual-layer printed
circuit board (PCB). It contains the MC33696 RF transceiver connected through an 8-bit MCHC908JW32
microcontroller to the USB. It’s main task is to receive data from the Sensor Board and transfer it to the
PC over the USB link.
PCB Antennas
MC33696
Button
LED indicators
MCHC908JW32
USB “A” Type Plug
Figure 4-1 USB Stick Board Overview
The USB stick board is powered from the USB. See Figure 4-2 for the stick board block diagram.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
31
USB Stick Board Description
+5 V USB
USB
SPI
MCHC908JW32
MCU
DATACLK
SEB
CONFB
STROBE
RSSIC
MC33696
433.92 MHz RF
MATCHING
CIRCUIT
Antenna
VDD
Figure 4-2 USB Stick Board Block Diagram
Figure 4-3 shows in more detail how different software and hardware modules co-operate with each
other. For the USB Stick board operation, several MCHC908JW32 peripheral modules are used.
• USB 2.0 Full-speed module (USB) - provides the interface with the PC
• Synchronous Peripheral Interface (SPI) - communication with the MC33696 (configuration and
receive)
• Timer/Pulse-Width modulator (TIM) - generates Manchester code for outgoing messages
• General Purpose Input/Output (GPIO) - control for the MC33696, button and LED’s
There are two main sw tasks running on the USB Stick board.
• receive data from the MC33696 transceiver and store in the RAM buffer
• handle the USB module communication, decode and provide the data from the RAM buffer
These two tasks are somewhat independent and the only common point between them is the
accelerometer, temperature, battery and buttons data buffer in RAM. The RF software communicates with
the Sensor Board and retrieves the latest accelerometer data. This is stored in RAM and can be
independently read by the PC application via the USB link. All transfers over RF are acknowledged. The
protocol employed on the PC side is just a subset of the simple STAR protocol used in the original
RD3112MMA7260Q demo. The protocol is described in Section 5.4.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
32
Freescale Semiconductor
ESTAR USB Stick Board Hardware Overview
MCHC908JW32
Software
Sensor & Button Data
“Virtual Serial Port”
or Mouse
USB Protocol
Handler
ESTAR RF Protocol Handler
Low-Level USB
Protocol Driver
ECHO Driver
Serial Peripheral Interface
(SPI) Module
Simple STAR
Protocol Handler
TIM
GPIO
USB 2.0
Full Speed Module
MC33696
USB Connection to PC
Figure 4-3 ESTAR USB Stick Board Software Overview
4.2 ESTAR USB Stick Board Hardware Overview
This section describes the USB Stick board in terms of the hardware design. The MCHC908JW32
microcontroller drives the MC33696 RF transceiver and communicates over USB with the PC. Refer to
Figure 4-2.
4.2.1 USB Connections
Two USB communication lines are connected directly via R1 to PTE2/D+ and R2 to PTE3/Dmicrocontroller pins. There, the R1 and R2 resistors define the output impedance of both drivers (ZDRV
as per chapter 7 of the USB 2.0 specifications).
Terminating the D+ line with a 1.5 kΩ pull-up resistor (required for full-speed signalling) is internal in the
MCHC908JW32.
A USB “A” type SMT Plug is designed at the edge of the USB Stick board allowing the stick to be
connected directly into a USB hub.
4.2.2 Power Supply
The USB Stick board uses a low-power bus-powered function for board power supply.The specifications
are defined in chapter 7.2.1.3 of the USB 2.0 specifications. This means that a maximum of one unit load
(100 mA) may be drawn by the USB Stick board.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
33
USB Stick Board Description
Voltage delivered by USB (VBUS) is defined as a minimum 4.4 V and a maximum 5.25 V on a Low-power
Bus-powered Function.
Ferrite beads are included on the VBUS and GND USB connections to minimize EMI. The recommended
type is listed in the BOM.
4.2.3 MC33696 to MCHC908JW32 Microcontroller Interface
On the USB Stick board, the full recommended MC33696 interface has been used. This includes the
following connections:
• 3-wire Synchronous Peripheral Interface (SPI) connection (MISO, MOSI, SPICLK)
• Output data from TIM module (DATA)
• Serial interface enable (SEB) signal
• Configuration control (CONFB) signal
• Strobe external control (STROBE) signal
• RSSI control (RSSIC) signal
• Data Clock signal (DATACLK)
The SPI connection is attached to the MCHC908JW32 SPI module signals (MISO, MOSI, SPCLK).
The STROBE signal is routed to GPIO signal PTA3.
The remaining three signals (SEB, CONFB and RSSIC) are connected to the GPIO signals of port D
(PTD0, PTD2 and PTD1).
All signals are described in more details in Section 3.4.6.
The MC33696 uses 5 V logic to interface with the MCU; the MC33696 also works with 3.3 V.
4.2.4 Oscillator and Clocking Options
The MCHC908JW32 microcontroller requires a stable clock, mainly for the Full-speed USB module
operations. USB specifications define an overall 2500 ppm (0.25%) accuracy. Basically, any generic
4 MHz crystal is sufficient for such accuracy. The main issue with 4 MHz crystals are their physical size.
Due to the nature of crystal resonating elements, the 4 MHz crystals are simply far too big for the USB
Stick in the ESTAR demo.
Another option is a SAW resonator (e.g., CERALOCKTM series from Murata). These are usually sorted
and selected by the manufacturer to fit the USB 2.0 Full-speed accuracy required. Today, only 6, 12, 24
and 48 MHz versions are available from Murata. A 6 MHz version has been used in the USB Stick design,
although the 6 MHz frequency is outside the MCHC908JW32 microcontroller specifications.
For final applications we recommended using a 4 MHz crystal that fits the current specification of the
MCHC908JW32 MCU.
4.2.5 LED Indicators Connections
The MCHC908JW32 microcontroller allows a direct drive of the LED’s on its three pins. PTB0, PTB1 and
PTB5 are high-current open-drain outputs, so the LED’s D1, D2 and D3 are connected to these
high-current outputs.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
34
Freescale Semiconductor
ESTAR USB Stick Board Hardware Overview
4.2.6 Button Connection
One button is implemented on the USB Stick board. It is connected to the IRQ microcontroller pin that has
an internal pull-up and allows for an easy software interrupt.
4.2.7 MON08 Interface
For MCHC908JW32 in-circuit programming, a MON08 interface is required. Several pins must be
connected to specific voltage levels in order for the MCHC908JW32 to enter the Monitor mode. The
details are described in the MCHC908JW32 data sheet, Chapter 7 Monitor ROM (MON).
To minimize the number of MON08 connections, several pins are hardwired to specific voltage levels
directly on the USB Stick board. Namely, PTA1 to Vdd, PTA2 and PTC1 to GND.
Pins PTA0, RST, IRQ and OSC1, together with the power supply lines, are routed to PCB pads MON08
connector (J3).
There is no standard physical connector to be soldered onto the J3 footprint. The J3 connector pads are
used during manufacturing for the initial in-circuit programming. Further re-programming of the USB Stick
maybe done using an AN2295 Bootloader as described in Section 5.5.
4.2.8 Optional Serial Interface
For the purpose of evaluating the USB functions of the MCHC908JW32 microcontroller, a few other pins
were routed to an additional PCB pads connector (J2). The two TIM timer pins are connected to J2
allowing emulation of SCI, IIC or such like serial interfaces in software. A simple example of a USB to
UART converter software is a part of the AN3153 Application Note - Using the Full-Speed USB Module
on the MCHC908JW32.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
35
R5
R4
R3
MIRQ
C2
100pF
Alps SKRP
3
4
GND
LED
D3
LED
D2
LED
D1
Q2
R7
1M
GND
VDD
1
25
26
OSC1
USB_DUSB_D+
R2 33R
R1 33R
J1
USB-A-MALE
GND
FB2
BEAD
1
2
3
4
FB1
BEAD
VDD
MRESET
MIRQ
OSC1
RXD
TXD
21
23
24
37
38
34
27
28
6
1
48
47
46
45
40
39
36
MRESET
MIRQ
GND
RxD
STROBE
PTA0
Murata CSTCR6M00G53
2
180
180
180
CONNECTORS, INTERFACES
GND
1
2
S1
GND
C10
2.2nF
R6
1k
VDD
VDD
VDD
C1
10nF
1
3
5
1
3
5
uMON08
J3
Serial
J2
2
4
6
2
4
6
VDD
GND
VDD
GND
2
3
12
20
MOSI
MOSI
SPICLK
MOSI
MISO
1
1
GND
RSSIC
1
GND
RSSIC
CONFB
1 SEB
CONFB
SEB
1
SPICLK
1
1
MOSI
MISO
TESTPOINTS
TxD
DATACLK
RxD
SEB
CONFB
RSSIC
13
14
15
16
17
18
19
22
7
4
41
5
USB_D+
USB_DSPICLK
MOSI
MISO
30
31
11
10
9
8
C3
1uF
1
C23
1nF
DATACLK
1 SWITCH
DATACLK
SWITCH
3.3pF
C22
L1
82nH
GND
C17
1nF
GND
C15
100pF
C14
100pF
C16
1nF
GND
4
3
SWITCH
GNDPA2
RFOUT
GNDPA1
VCC2VCO
GNDLNA
RFIN
VCC2RF
RSSIOUT
VCC_33V
8
7
6
5
4
3
2
1
U1
1nF
Q1
C6
NX3225GA 24MHz
1
2
GND
C5
6.8pF
C20
1pF
VCC_33V
Figure 4-4 USB Stick Schematics
PTA0
GND
NC
NC
NC
NC
GND
NC
NC
NC
PTD0
PTB0
PTD1
PTB1
PTD2
PTB5 U2
PTD3
MC68HC908JW32FC PTD4
PTD5
RESET
PTD6
IRQ
PTD7
CGMXFC
PTC0/T1CH0
PTC1/TCLK1
OSC1
PTC2/T1CH1
OSC2
PTC3
PTE2/PS2CLK/D+
PTE3/DPTE4/SPCLK
PTE5/MOSI
PTE6/MISO
PTE7/SS
43
PTA0/KBA0
PTA1/KBA1
PTA2/KBA2
PTA3/KBA3
PTA4/KBA4
PTA5/KBA5
PTA6/KBA6
PTA7/KBA7
32
REG25V
C4
100nF
35
REG33V
C13 C12
100p1nF 5%
VDD
MC33696
ECHO+
100nF
GND
100nF
C7 C8
100nF
C9
MISO
MOSI
SCLK
R8
470K - 1%
GND
GNDDIG
RSSIC
DATACLK
SEB
SPICLK
MOSI
MISO
CONFB
DATACLK
RSSIC
GND
23
22
21
20
19
18
17
TO MCU
24
GND
SEB
C11
100n
CONFB
10
MC33696 + RF
XTALOUT
VDD
VCCINOUT
11
GND
32
GND
VCC2OUT
12
MCU, USB, RS232, MON08
1
2
1
2
29
GNDSUBD
VCCDIG
13
L3
15nH
28 STROBE
STROBE
VCCDIG2
14
42
EPGND
EPGND
EPGND
EPGND
EPGND
EPGND
EPGND
EPGND
EPGND
108
107
106
105
104
103
102
101
100
27
LVD
15
VDD
VSS33
VSSPLL
29
33
31
XTALIN
26
VCCIN
RBGAP
VDDPLL
VSS
44
30
VCC2IN
SWITCH
9
25
GNDIO
GND
Freescale Semiconductor
16
4.2.9 USB Stick Schematics
ESTAR USB Stick Board Hardware Overview
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
36
Bill of Materials
4.3 Bill of Materials
Table 4-1USB Stick Bill of Material
Item
Quantity
1
1
C1
Reference
10nF
Part
AVX
Manufacturer
06035C103KAZ2A
Manufacturer Order Code
2
4
C2,C13,C14,C15
100pF
AVX
06035A101JAT2A
3
1
C3
1uF
PHYCOMP
223824619863
4
1
C5
6.8pF
PHYCOMP
223886715688
5
4
C6,C16,C17,C23
1nF
AVX
06035C102KAT2A
6
5
C4,C7,C8,C9,C11
100nF
AVX
06033G104ZAT2A
7
1
C20
1pF
PHYCOMP
223886715108
8
1
C22
3.3pF
AVX
06032U3R3BAT2A
9
1
C10
2.2 nF
AVX
06035C222KAZ2A
10
1
C12
1 nF 5%
AVX
06035A102JAT2A
11
3
D1,D2,D3
KP-1608SEC
Kingbright
KP-1608SEC
12
2
FB1,FB2
Ferrite bead
TDK
GLF1608T100M
13
1
J1
USB-A-MALE
Molex
48037-1000
14
1
J2
Serial
N/A
only footprint
15
1
J3
MON08
N/A
only footprint
16
1
L1
82nH
TDK
MLG1608B82NJT
17
1
L3
15nH
TDK
MLG1608B15NJT
18
1
Q1
NX3225GA 24MHz
NDK
NX3225GA 24MHz
S1-4085-8050-8
19
1
Q2
CSTCR6M00G15
Murata
CSTCR6M00G15
20
2
R1,R2
33R
resistor 0603 package
any available
21
3
R3,R4,R5
820R
resistor 0603 package
any available
22
1
R6
1k
resistor 0603 package
any available
23
1
R7
1M
resistor 0603 package
any available
24
1
R8
470k - 1%
resistor 0603 package
any available
25
1
S1
Alps SKRP
ALPS
SKRPAB
26
1
U1
MC33696
Freescale
MC33696FJE/R2
27
1
U2
68HC908JW32
Freescale
68HC908JW32
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
37
USB Stick Board Description
4.4 USB Stick Layout
Copper
Silk Screen
Solder Mask
Top
53mm
26 mm
Bottom
26mm = 1.02 in
53mm = 2.09 in
Figure 4-5 USB Stick PCB layout (1:1)
4.5 Memory Usage in MCHC908JW32
Table 4-2. Memory Usage in MCHC908JW32
Memory usage in MCHC908JW32 for Virtual Serial Port Application
Type
Hexadecimal Value
Decimal Value
READ_ONLY (R)
2DA3
11683
READ_WRITE (R/W)
1AA
426
Memory Usage in MCHC908JW32 for HID Class Application
READ_ONLY (R)
1820
6176
READ_WRITE (R/W)
119
281
Available Memory in MCHC908JW32
READ_ONLY (R)
8000
32768
READ_WRITE (R/W)
400
1024
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
38
Freescale Semiconductor
Chapter 5
Software Design
5.1 Introduction
This section describes the design of the ESTAR software blocks (mainly communication, because others
are general code which needn’t be described). The software description comprises these topics:
• ECHO Driver modifications description
• ‘Air’ ESTAR RF Protocol protocol description
• Serial STAR Protocol and ESTAR Extensions (over USB) protocol description
• AN2295 Bootloader (over USB) implementation notes
• Accelerometer reading in Section 3.2
5.2 ECHO Driver
The Echo driver is a simple ANSI C based code stack available as sample source code which can be used
to develop proprietary RF transceiver applications using the MC33696.
5.2.1 Echo Driver Features
•
•
•
•
•
•
Compact footprint:
– 2.1K FLASH
– 77 bytes + transmit buffer (MAX_DATA) + receive buffers((MAX_DATA+2) x count buffers)
RAM
MC33696 compatible
Very-low power, proprietary, bi-directional RF communication link
ANSI C source code targeted at the HCS08 and HC08 core
Sample application included, extremely easy to use
Liberally commented
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
39
Software Design
5.3 ESTAR RF Protocol
The ESTAR demo uses very simple protocol to transfer the accelerometer, button, voltage, temperature
and calibration data between the Sensor Board and the USB Stick over the RF medium. The protocol is
built on top of the ECHO Driver drivers that are available for the MC33696 transceiver.
All data is transferred in packets. This protocol is primarily targeted at simple demo purposes, allowing a
fast transfer of the accelerometer data in short packets with minimum overheads and with minimum
battery loads (most of the receive windows are eliminated, short transmit packets, etc.).
5.3.1 Packet Format
The ESTAR packet is contained inside the MC33696 standard packet structure.
The used packet becomes a payload data for the MC33696 standard packet and contains the following
fields:
• ID
• Header
• Command
• RX Strength
• Data
RF Signal
P+ID
P+ID
P+ID
P+ID
P+ID
P+Header
Data
EOM
P+ID Preamble+ID
Echo Driver Packet Format
P+Header Preamble+Header
EOM
End Of Message
Packet
Length
Data
Only for
Sensor
USB
ESTAR Packet Structure
Command
RX
Strength
Data
ESTAR Command Byte Structure
4 Status Bits
4-Bits Command
Figure 5-1 Packet Format
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
40
Freescale Semiconductor
ESTAR RF Protocol
5.3.1.1 ID
The ID value is used for identifying both transmitting and receiving devices. Packets with a different ID
are simply ignored.
This field is 6 bits long.
5.3.1.2 Header
The Header serves as identification sequence bits at the start of the load data bits.
This field is 4 bits long.
5.3.1.3 Command
This byte is split into two parts: the lower 4 bits contain the command number, the upper 4 bits contain
the status bits. The upper bits - status is defined as follows:
• Sensor Board to USB Stick
– MODE_BIT (0x20) - shows which mode of operation (16/8 - bits) the Sensor Board just worked
in
– ACK_BIT (0x10) - informs the USB board if a previous acknowledgment was received
• USB Stick to Sensor Board
– MODE_BIT (0x20) - informs the Sensor Board which is the latest mode of operation
– G_SEL bits (0x80,0x40) - these bits transmit the actual request for MMA7260Q scale to the
Sensor Board. The g-range data is intended to switch the g-range of the accelerometer sensor.
The lower bits contains commands which are defined and listed in Table 5-1.
Table 5-1 ESTAR Command List
Command
Command Code
Direction
Data
CMD_TEST
(0x01)
Both
none
CMD_TRIAX_DATA
(0x02)
Sensor Board to USB Stick
accelerometer values, button levels,
voltage, temperature
CMD_ACK
(0x04)
USB Stick to Sensor Board
acknowledgment for CMD_TRIAX_DATA
CMD_CALIB_R
(0x05)
Both
calibration data from Sensor Board and
request for it
CMD_CALIB_W
(0x06)
USB Stick to Sensor Board
calibration data to Sensor Board
CMD_CALIB_ACK
(0x07)
Sensor Board to USB Stick
acknowledgment for CMD_CALIB_W
command
5.3.1.4 RX Strength
This field reports the strength of the last received packet on the Sensor Board. This value simply tells us
how well the other side receives ‘our packets’. This is used only for additional ESTAR command over USB
protocol Signal Strength (user friendly) ’s’(0x73).
This field is 8 bits long.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
41
Software Design
5.3.1.5 Data
The Data field follows the Command field and may be empty if the actual command doesn’t require any
additional data. The data format is dependent on the Command. A detailed description is in the next
chapter.
5.3.2 ESTAR Protocol Commands Description
5.3.2.1 CMD_TEST
This command is sent when the Sensor Board tries to establish connection with the USB Stick. The
Sensor Board first sends this command and then waits for response. This sequence is repeated several
times until it gets a response. Once a USB Stick receives this command, it responds with a CMD_TEST
command.
5.3.2.2 CMD_TRIAX_DATA
Once the connection is established, the Sensor Board starts to periodically transmit accelerometer,
button, voltage, temperature and g-range status data towards the USB Stick.
The Data field contains 11 or 6 bytes, depending on actual working mode; the actual X, Y and Z
accelerometer values, a byte with status information, raw temperature and raw voltage.
Data Bytes:
0
1
Status
2
3
X Value
g-Range
bits:
msb
7
6
4
Y Value
5
6
Z Value
Unused
7
8
9
Raw
Temperature
10
Raw
Voltage
Button 2 Button1
5-2
1
0
lsb
Figure 5-2 CMD_TRIAX_DATA Data Format
Each transmission of a CMD_TRIAX_DATA packet is acknowledged by a CMD_ACK packet from the
USB Stick.
5.3.2.3 CMD_ACK
This command is sent as the data acknowledgement for CMD_TRIAX_DATA so the Sensor Board is
informed that the connection is still alive. If the receive window is opened by the Sensor Board and the
CMD_ACK has not been received, the operation (periodic transmission of a CMD_TRIAX_DATA packet)
continues but the Sensor Board will cut the dead time (the time till board switch off) by ~40 seconds. When
dead time counter overflows, the Sensor Board goes into deep sleep mode.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
42
Freescale Semiconductor
ESTAR RF Protocol
5.3.2.4 CMD_CALIB_R
This command is used for two purposes.
1. From the USB Stick to the Sensor Board - used as a request to read the calibration data stored in
the Sensor Board Flash memory
2. From the Sensor Board to the USB Stick - used as a reply to the request and immediately transmits
a message with the same command along with the calibration data. The data format is shown in
Figure 5-3:
Data Bytes:
0
1
X value (0 g)
2
3
X value (1 g)
4
5
Y value (0 g)
6
7
Y value (1 g)
8
9
Z value (0 g)
10
11
Z value (1 g)
Figure 5-3 CMD_CALIB_R Data Format
5.3.2.5 CMD_CALIB_W
This command carries the calibration data provided by the USB Stick for the Sensor Board and is sent
instead of a CMD_ACK packet. The calibration data is intended to be stored in the Sensor Board Flash
memory. The USB Stick keeps sending a CMD_CALIB_W until the Sensor Board confirms receipt using
a CMD_CALIB_ACK packet.
5.3.2.6 CMD_CALIB_ACK
This command is only used to acknowledge command CMD_CALIB_W as described in Section 5.3.2.5.
5.3.3 ESTAR RF Protocol Description
State machines are implemented in both devices for RF protocol. Each device has slightly different steps
because they have different functions and requirements on power saving. All other services in the USB
Stick are based on interrupts routines.
5.3.3.1 USB Stick RF State Machine
The state machine in the USB Stick contains 4 states:
1. NOT INIT - in this state software inits all software and hardware resources for RF. After everything
has been initialized, the software jumps to the next state NO_RF.
2. NO_RF - in this state, the software waits for the first transmission from the Sensor Board. After
receiving a proper message with the CMD_TEST command, the state machine passes over to
ACTIVE_RF. LED1 and LED2 are blinking in this state.
3. ACTIVATE_RF - this state activates the service for the first information exchange between the
Sensor Board and the USB Stick (mainly calibration data saved on the Sensor Board).When all the
first transmissions have finished the software jumps to the final state, RF_WORK.
4. RF_WORK - in this state the software is periodically receives a transmission from the air and
services it. If no transmission is received in a long time (time is set to <10s), the software
automatically jumps to the first state NOT_INIT.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
43
Software Design
5.3.3.2 Sensor Board RF State Machine
The state machine in the Sensor Board has 4 steps too, but different:
1. NOT_INIT - this state has a very similar function to the NOT_INIT state of the USB Stick state
machine.
2. NO_RF - in this state, the software periodically transmits a preliminary command CMD_TEST and
then waits for the correct reply. If the Sensor Board doesn’t receive a correct answer, then
transmission is repeated up to 30 times and then the Sensor Board goes into the RF_SLEEP state.
If the Sensor Board receives a correct answer then the state machine jumps to state RF_WORK.
3. RF_WORK - in this state the software periodically transmits data to the USB Stick by
CMD_TRIAX_DATA and answers all other commands from the USB Stick (mainly the
CMD_CALIB_W command). During this time there is dead running time which can send the device
into sleep mode (RF_SLEEP). Under normal conditions this time is set as 2 minutes from the last
button press, but if the Sensor Board doesn’t receive any acknowledgement after 8 consecutive
transmissions, the dead time is reduced by ~40 seconds. If dead time overflows, the state machine
jumps to the final state of RF_SLEEP.
4. RF_SLEEP - in this state the software only switches off the periodic timer for the
CMD_TRIAX_DATA and puts the device into sleep mode. When any button on the Sensor Board
is pushed, the system is woken up and the state machine is set to NOT_INIT state.
5.3.3.3 RF Communication Overview, Establish Connection Time Flow
Complete initialization of RF communication takes only six steps under ideal conditions, as shown in
picture Figure 5-4. This figure shows a really ideal situation, but the reality is different. In these cases, the
ESTAR can repeat all commands and transfers until it receives a correct answer or the dead counter in
any device overflows.
Step 1. - After the Sensor Board wakes up from sleep mode it periodically sends the CMD_TEST
command. Then the USB Stick can receive one of many CMD_TEST commands and jumps into the
ACTIVATE_RF state.
Step 2. - The Sensor Board doesn’t know that the USB Stick has received the CMD_TEST command and
sends the next one.
Step 3. - The USB Stick is in the ACTIVATE_RF state and generates an acknowledgment (CMD_TEST)
in reply to the CMD_TEST command from the Sensor Board.
Step 4. - Because the Sensor Board is placed in the RF_WORK state, it starts to periodically generate
the CMD_TRIAX_DATA command and send it over the air.
Step 5. - The USB Stick is still in the ACTIVATE _RF state. After the command CMD_TRIAX_DATA is
received from the Sensor Board, USB Stick requests calibration data using the CMD_CALIB_R
command.
Step 6. - If the Sensor Board receives in the RF_WORK state a CMD_CALIB_R command, it immediately
sends the actual calibration data saved in Flash memory. When the USB Stick receives this message the
preparation stage for communication ends, and both devices are ready for normal communication.
Step n. - The Sensor Board continues transmitting CMD_TRIAX_DATA messages and waits for an
acknowledgment CMD_ACK from the USB Stick board.
Step n+1. - After each correctly received CMD_TRIAX_DATA command from the Sensor Board, the USB
Stick transmits a CMD_ACK command as an acknowledgment.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
44
Freescale Semiconductor
ESTAR RF Protocol
Step x. - This step is used only when the user writes calibration data to the Sensor Board over a terminal
or GUI (RD3152MMA7260Q_SW.exe). The USB Stick transmits a CMD_CALIB_W command with the
new calibration data.
Step x+1. - When the Sensor Board receives a CMD_CALIB_W command with new calibration data, it
immediately transmits a CMD_CALIB_ACK command as an acknowledgment.
Sensor Board
NOT_INIT
USB Stick Board
AIR
NOT_INIT
1. step - S->U req. CMD_TEST
NO_RF
NO_RF
2. step - S->U req. CMD_TEST
3. step - U->S ack. CMD_TEST
4. step - S->U data CMD_TRIAX_DATA
ACTIVATE_RF
5. step - U->S req. CMD_CALIB_R
6. step - S->U data CMD_CALIB_R
n. step - S->U data CMD_TRIAX_DATA
RF_WORK
n+1. step - U->S ack. CMD_ACK
x. step - U->S data CMD_CALIB_W
RF_WORK
x+1. step - S->U ack. CMD_CALIB_ACK
RF_SLEEP
S->U - Sensor to USB
U->S USB to Sensor
req. - request
ack. - acknowledgment
data - data message
Time
Figure 5-4 RF Protocol Overview of Both Software State Machines in Both Devices
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
45
Software Design
5.4 STAR Protocol and ESTAR Extensions (over USB)
The ESTAR demo uses a subset of the original STAR demo protocol commands. This way, most of the
software originally developed for the RD3112 (STAR) is also usable with the ESTAR.
The STAR demo communicates over the RS232 serial line with a simple text-based protocol. The same
protocol is used in ESTAR for communication between the USB Stick and a PC (over a virtual serial port).
The PC application sees the same interface (serial port) and the same protocol as if a STAR demo was
connected.
5.4.1 Communication Handshake ‘R’ (0x52)
Initially, a handshake (commands needed to test/establish the connection between the PC and the
ESTAR demo) is conducted. This is accomplished by the PC sending an ‘R’ command, the ESTAR demo
responding with ‘N’. In this way, the PC application sees that the demo is ready for communication.
Communication is reset, operation mode is set to 8-bit (default value) and any debug or system modes
are disabled.
All subsequent commands will carry only 8-bit values (backward compatibility).
‘R’
PC to demo
‘N’
demo to PC
Figure 5-5 Communication Handshake ‘R’ (0x52)
5.4.1.1 Extended Communication Handshake ‘r’ (0x72)
To determine whether an ESTAR or STAR demo is connected, the ESTAR (and ZSTAR) demo
implements an Extended Handshake Communication command. Once the PC sends the ‘r’ command,
the ESTAR demo responds with a ‘z’ and switches itself to 16-bit mode.
All subsequent commands will carry left justified 16-bit values (extended values). The communication
uses big endianism, i.e., more significant byte first.
‘r’
PC to demo
‘z’
demo to PC
Figure 5-6 Extended Communication Handshake ‘r’ (0x72)
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
46
Freescale Semiconductor
STAR Protocol and ESTAR Extensions (over USB)
5.4.2 Accelerometer Data Transfer ‘V’ (0x56)
The PC sends the Values ‘V’ command, the demo responds with 6 bytes (or 9 bytes in 16-bit mode) in
the following sequence:
'x', X-value, 'y', Y-value, 'z', Z-value, simply an ‘x’ character followed by the actual X-axis accelerometer
binary value, then a ‘y’ followed by the actual Y-axis accelerometer binary value and a ‘z’ followed by the
actual Z-axis accelerometer binary value. Since the ESTAR demo caches the last (over the air)
transmitted values, these values are immediately provided to the PC.
‘V’
PC to demo
‘x’
X-axis value
‘y’
Y-axis value
‘z’
Z-axis value
demo to PC
Figure 5-7 Accelerometer Data Transfer ‘V’ (0x56)
5.4.2.1 Extended Accelerometer Data Transfer ‘v’ (0x76)
The ESTAR demo has two buttons placed on the Sensor Board. The microcontroller on the Sensor board
is capable of measuring the internal bandgap voltage reference and temperature. To acquire the actual
state of these values, the original ‘V’ command has been extended to a ‘v’ command, providing the same
information, followed by a ‘s’ character and a binary byte containing the actual state. The least two
significant bits are used, the others are used for packet error ratio. If a button is pressed, the actual bit is
set to ‘1’, otherwise, the bit is ‘0’.
The status data is followed by a ‘t’ character with the raw temperature value, and finally a ‘b’ character
followed by the raw bandgap voltage value.
‘v’
PC to demo
‘x’
X-axis
value
‘y’
Y-axis
value
‘z’
Z-axis
value
‘s’
buttons +
packet err
‘t’
raw
temperature
‘b’
raw
bandgap
demo to PC
Figure 5-8 Extended Accelerometer Data Transfer ‘v’ (0x76)
To obtain a true battery voltage from the raw bandgap value, the following formula may be used:
65536
V batt = ------------------------- ¥ 1.20V
rawbgap
(5-1)
assuming rawbgap has a 16-bit format value. In 8-bit mode, the number 65536 must be changed to 256.
The real temperature can be calculated from the bandgap reference voltage and the raw temperature
value; first, the true voltage of the temperature sensor is obtained:
rawtemperature
V temp = ---------------------------------------------- ¥ 1.20V
rawbgap
(5-2)
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
47
Software Design
then, if the temperature is above 25°C, i.e. voltage is above 0.7012V, the real temperature is:
V temp – 0.7012
temperature = 25 – ⎛⎝ ----------------------------------------⎞⎠
0.001646
(5-3)
otherwise (temperatures below 25°C):
V temp – 0.7012
temperature = 25 – ⎛⎝ ----------------------------------------⎞⎠
0.001769
(5-4)
5.4.3 Calibration Data ‘K’ (0x4B)
The calibration data is the accelerometer values for specific g (acceleration) levels. The values for 0 g and
1 g (Earth gravity) are provided for each axis. These values are stored in the Flash memory of the Sensor
Board and are transferred to the USB Stick once the air connection is established (as described in
Section 5.3.2.4). These values are stored in the USB Stick for retrieval by the PC using the ‘K’ command.
The PC sends the Calibration data ‘K’ command, the demo responds with 9 bytes in 8-bit mode (or 15
bytes in 16-bit mode) in the following sequence:
'X', Xval0, Xval1, 'Y', Yval0, Yval1, Z', Zval0, Zval1, simply an ‘X’ character followed by the 0g and 1g
X-axis calibration accelerometer binary values, and the same for Y- and Z-axes.
‘K’
PC to demo
‘X’
x (0 g) x (1 g)
‘Y’
y (0 g) y (1 g)
‘Z’
z (0 g) z (1 g)
demo to PC
Figure 5-9 Calibration Data ‘K’ (0x4B)
5.4.4 Calibration Process ‘k’ (0x6B)
The calibration process is initiated by a ‘k’ command from the PC, followed by 6 bytes of calibration data.
These are stored in the Flash memory of the Sensor Board. More in Section 5.3.2.5.
The calibration data contains 6 bytes in 8-bit mode (or 12 bytes in 16-bit mode) in the following sequence:
Xval0, Xval1, Yval0, Yval1, Zval0, Zval1 - 0g and 1g calibration accelerometer binary values for X-, Yand Z-axes. No response from the demo is provided. Verification of the calibration data stored can be
done using the Calibration Data ‘K’ (0x4B) command.
‘k’
x (0 g)
x (1 g) y (0 g)
y (1 g)
z (0 g)
z (1 g)
PC to demo
demo to PC
Figure 5-10 Calibration Process ‘k’ (0x6B)
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
48
Freescale Semiconductor
STAR Protocol and ESTAR Extensions (over USB)
5.4.4.1 Remaining STAR Demo Commands
The remaining STAR commands, such as 'F', 'G', 'H', '0', '1', '2', '3' and 'E' are not yet implemented in this
version of the ESTAR demo.
5.4.5 Additional ESTAR Commands
5.4.5.1 g-Select Reading ‘G’ (0x47)
The ESTAR demo allows dynamic selection of the g-range for the accelerometer sensor (see details in
Section 3.4.2), thus additional commands are implemented to read and change the g-range.
When the PC issues a ‘G’ command, the ESTAR demo responds with the g-range actually selected. A
‘0’, ‘1’, ‘2’ or ‘3’ character is returned where ‘0’ is for the 1.5g range, ‘1’ for 2.0g, ‘2’ for 4.0g and ‘3’ for the
6.0g range. If a different sensor (e.g. MMA7261QT) is implemented on the Sensor Board, the g-ranges
are 2.5g, 3.3g, 6.7g and 10g respectively.
‘G’
PC to demo
g-select value
demo to PC
Figure 5-11 g-Select Reading ‘G’ (0x47)
5.4.5.2 g-Select Setting ‘g’ (0x67)
To select the g-range of the sensor on the ESTAR Sensor Board, a ‘g’ command is issued. It needs to be
followed by the required g-range (‘0’, ‘1’, ‘2’ or ‘3’). The USB Stick board then communicates this selection
to the Sensor Board over the air (see more in Section 5.3.1.3).
No response from the demo is provided. To verify which g-range has been selected, the g-Select Reading
‘G’ (0x47) command can be used.
‘g’
g-select value
PC to demo
demo to PC
Figure 5-12 g-Select Setting ‘g’ (0x67)
5.4.5.3 Info ‘I’ (0x49)
The Info command ‘I’ has only been added to determine which version, compile date, and author of the
USB Stick software has been implemented. The demo returns plain text information, and this command
is usually issued over terminal (e.g., HyperTerminal) software.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
49
Software Design
‘I’
PC to demo
info text, version, date, etc.
demo to PC
Figure 5-13 Info ‘I’ (0x49)
5.4.5.4 ESTAR Help ‘H’(0x48), ‘h’(0x68)
The help command only returns plain text information on all ESTAR commands; this command is
implemented for an easier human interface over a terminal
‘H’ or ‘h’
PC to demo
Help text for ESTAR commands
demo to PC
Figure 5-14 ESTAR Help ‘H’(0x48), ‘h’(0x68)
5.4.5.5 Signal Strength (user friendly) ’s’(0x73)
This command return in a user friendly representation values on the receive strength signals for both
devices. Values are in hex code and the scale is 0x00 - 0x1F.
‘s’
PC to demo
Information on the signal strength both devices
demo to PC
Figure 5-15 Signal Strength (user friendly) ’s’(0x73)
5.4.5.6 Signal Strength (binary) ‘S’(0x53)
This command sends the same information as the command Signal Strength (user friendly) ’s’(0x73), but
in binary code. It’s designed for the demo application RD3162MMA7260Q_SW.exe.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
50
Freescale Semiconductor
STAR Protocol and ESTAR Extensions (over USB)
‘S’
PC to demo
‘s’
RSSI
USB
RSSI
key
demo to PC
Figure 5-16 Signal Strength (binary) ‘S’(0x53)
5.4.5.7 Read MC33696 Registers on USB Dongle ‘A’(0x41), ‘a’(0x61)
The USB Stick reads all the MC33696 registers (bank A) on the board and then returns them in friendly
mode to the terminal. All values are in hex code.
‘A’ or ‘a’
PC to demo
Return MC33696 registers values
demo to PC
Figure 5-17 Read MC33696 Registers on USB Dongle ‘A’(0x41), ‘a’(0x61)
5.4.5.8 Temperature and Battery ‘T’(0x54), ‘t’(0x74)
The Temperature and battery command returns the received temperature and battery values from the
Sensor Board in user friendly mode. Temperature is in non computed raw format (hex), but battery voltage
is calculated in the USB Stick up to two digits after decimal point. If the Sensor Board is not connected,
the USB Stick informs the user.
‘T’ or ‘t’
PC to demo
Information on the Sensor board temperature and voltage
demo to PC
Figure 5-18 Temperature and Battery ‘T’(0x54), ‘t’(0x74)
5.4.5.9 Working Mode ‘M’(0x4D), ‘m’(0x6D)
The USB Stick returns the actual working mode (8/16 bit) for both devices in user friendly mode. If the
Sensor Board is not connected, the USB Stick informs the user.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
51
Software Design
‘M’ or ‘m’
PC to demo
Information on the mode (8-16bit) for both devices
demo to PC
Figure 5-19 Working Mode ‘M’(0x4D), ‘m’(0x6D)
5.4.5.10 Show Calibration Data ‘q’(0x71)
The command Show calibration data ‘q’ returns calibration data from RAM memory in the USB Stick. If
the Sensor Board is not connected the command returns the value from the last communication with it. If
the sensor board has never been connected, the command returns the default values from Flash memory.
‘q’
PC to demo
Calibration data shown in decimal system
demo to PC
Figure 5-20 Show Calibration Data ‘q’(0x71)
5.4.5.11 Read g-Select ‘N’(0x4E),’n’(0x6E)
This command has a similar function as in Section 5.4.5.1). The only difference is in visualization. This is
a user friendly command. If the Sensor Board is not connected, the USB Stick informs the user.
‘N’ or ‘n’
PC to demo
G-select information in user friendly mode
demo to PC
Figure 5-21 Read g-Select ‘N’(0x4E),’n’(0x6E)
5.4.5.12 Debug On ‘U’ (0x55) and Debug Off ‘u’ (0x75)
Various debug information can be observed after issuing a ‘U’ command, usually using terminal (e.g.
HyperTerminal) software. Mainly, information on the air protocol is displayed in text.
The debug information is no longer displayed after issuing a ‘u’ command or Communication Handshake
‘R’ (0x52).
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
52
Freescale Semiconductor
Bootloader
‘U’
‘u’
PC to demo
various debug information
mainly on air protocol
no debug info
demo to PC
Figure 5-22 Debug On ‘U’ (0x55) and Debug Off ‘u’ (0x75)
5.4.6 Further Debug and Test Commands
5.4.6.1 Semi-Automatic Self-Calibration
For the purpose of easier semi-automatic calibration of the ESTAR demo, an additional Calibration
command ‘Q’ (0x51) has been added. This command is usually issued over terminal (e.g. HyperTerminal)
software.
A user is required to place the Sensor Board into 3 specific positions, in which the Earth gravity will induce
a maximum acceleration in each of X, Y, and Z axes. After issuing the first ‘Q’ command, the Sensor
Board must be placed flat, i.e. with the Z-axis aiming towards the Earth’s core. After the second issue of
a ‘Q’ calibration command, the board’s X-axis has to be aimed towards the Earth’s core. The board should
‘stay’ on its right edge. Next, the Y-axis is calibrated, with the board ‘staying’ on its top edge. Finally, after
issuing the fourth ‘Q’ command, the calibration data is sent to the Sensor Board, actually using the
CMD_CALIB_W command. Text help is provided during the self-calibration process.
5.5 Bootloader
There’s bootloader software implemented in MCHC908JW32 microcontroller. The bootloader is based on
AN2295 Application Note - Developer’s Serial Bootloader for M68HC08 and HCS08 MCU’s and
AN2295SW accompanied software. The original AN2295 bootloader targets serial connections between
the PC and applications, and since the MCHC908JW32 implements a virtual serial port application, the
USB version of the AN2295 bootloader has been created to allow reprogramming of Flash memory in the
USB Stick.
The USB virtual serial port software is fully described in AN3153 Application note - Using the Full-Speed
USB Module on the MCHC908JW32; the MCHC908JW32 bootloader implements the same virtual serial
port but under a different PID (the PC sees that serial port as a different application from ESTAR).
The bootloader drivers installation guide can be found in chapter 6.1.2 of AN2295 Bootloader Drivers
Installation.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
53
Software Design
5.5.1 Bootloading Procedure
1. Find the folder with binaries on the installation CD:
2. Start (double-click) the CMD.EXE shortcut, a command line window should appear:
3. Now type: hc08sprg [bootloader com port number] [binary (S file) that you want to bootload], just
like this:
hc08sprg.exe com6 ESTAR_Dualboot.S19
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
54
Freescale Semiconductor
Bootloader
4. Press ENTER and initial bootloader communication will start:
If this screen does not appear, remove the USB stick and start from the beginning.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
55
Software Design
5. Just confirm with Y, and the binary will be loaded onto the USB stick:
The bootloader disappears (in Device Manager) and the newly loaded software starts to execute.
Using this procedure the software in the USB Stick can be changed anytime.
5.5.2 Dualboot Guidelines
NOTE:
The USB Stick comes with two factory set dualboot-aware applications
already pre-programmed.
USB Stick and AN2295 Bootloader software provide a way of having two different software (devices) in
one USB Stick. In order to do this, two dualboot-aware versions of the software need to be consecutively
bootloaded onto the USB Stick:
Follow the sequence of instructions in the 5.5.1 Bootloading Procedure for two dualboot versions of
software:
1. First bootload ESTAR_Dualboot.S19.
After bootloading, ESTAR Triaxial Demo (COMx) should appear in Device Manager.
2. Next, remove the USB stick again, press the button, re-insert the stick and bootload
HID ESTAR_Dualboot.S19 software in.
After bootloading, a new device (ESTAR Triaxial Mouse) should appear:
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
56
Freescale Semiconductor
Bootloader
The ‘tilt’ mouse will install automatically and also appear in the Device Manager:
5.5.2.1 Dualboot Applications Switching
Having both dualboot-aware applications programmed onto the USB Stick, they can be switched just by
quickly pressing the button (having the USB Stick inserted into the USB slot). The applications will appear
and disappear accordingly.
Please note that the ‘tilt’ mouse application must have sensor board calibrated correctly (e.g. using
RD3152MMA7260Q_SW.exe or Semi-Automatic Self-Calibration procedure).
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
57
Software Design
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
58
Freescale Semiconductor
Chapter 6
Application Setup
6.1 ESTAR Installation Procedure
6.1.1 USB stick Installation
First of the all, install the USB stick to your PC. Please follow the next steps.
1. Plug the USB stick into a USB slot.The ‘Found New Hardware’ announcement should appear:
2. Then the installation wizard starts searching for new hardware. Choose “Install from a list or special
location”
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
59
Application Setup
3. Point to the Installation CD as the driver path:
4. Installation should continue:
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
60
Freescale Semiconductor
ESTAR Installation Procedure
5. If you are using Windows XP SP1, you will be asked to stop or continue installation because the
drivers are not certified by Microsoft. Select the “Continue Anyway” button
6. Installation should successfully finish.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
61
Application Setup
7. Check whether a new serial port (ESTAR Triaxial Demo) has appeared in your Device Manager
(My Computer, right click, Manage, Device Manager):
8. If required, the ESTAR Triaxial Demo COM port may be renumbered using the standard procedure
in the Windows operating system:
Right click for Properties, Port Settings tab, Advanced button and change the COM port number
accordingly.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
62
Freescale Semiconductor
ESTAR Installation Procedure
9. Launch the RD3152 software “RD3152MMA7260QSW.exe" and select the COM port number
which you may have assigned in Device Manager.
If no error message appears, the COM port is opened correctly and the software communicates with the
USB stick.
10. Now let’s go and check the data from the ESTAR Sensor Board.
Raw data, 2D/3D screen, or Scope work should be used for this purpose. While moving (turning, shaking)
with an ESTAR Sensor Board, data from each separate axis should change accordingly.
The RD3152MMA7260QSW calibration screen can be used for sensor calibration (calibration data is
stored in the Sensor Board).
6.1.2 AN2295 Bootloader Drivers Installation
This procedure assumes that ESTAR Demo drivers are already installed. The drivers are also common
for the bootloader (= are already present in the Windows folders). If not, the procedure will be identical to
the ESTAR drivers installation.
1. Press the Button on the USB stick and insert it into a USB connector (keeping the button pressed
when inserted).
The following window appears:
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
63
Application Setup
2. The PC searches for an appropriate driver (as in the ESTAR Demo, in some instances a folder with
drivers (star.inf and usbser-zstar.sys) needs to be selected).
3. If the PC shows a window for a digital signature then click Yes, and the bootloader port will be
installed (as seen in the Device manager):
4. Right click My computer on the Desktop > Properties, Hardware tab, Device Manager button.
5. A similar setup should be observed:
6. Note down the COM port number (here, COM8); this is the port number of the Bootloader.
When the software in the USB stick needs to be updated, the Bootloader can be invoked anytime, just by
pressing the button while inserting the USB stick into the USB slot.
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
64
Freescale Semiconductor
Appendix A
References
The following documents can be found on the Freescale web site: http://www.freescale.com.
1.
2.
3.
4.
5.
6.
7.
AN2295 Application Note - Developer’s Serial Bootloader for M68HC08 and HCS08 MCU’s
AN3153 Application Note - Using the Full-Speed USB Module on the MCHC908JW32
MC9S08QG8 Datasheet
MCHC908JW32 Datasheet
MMA7260QT Datasheet
USB2.0 Specification (www.usb.org)
AN2961 Echo Driver Software
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
Freescale Semiconductor
65
434 MHz Wireless Triple Axis Accelerometer Reference Design, Rev. 0
66
Freescale Semiconductor
How to Reach Us:
Home Page:
www.freescale.com
Web Support:
http://www.freescale.com/support
USA/Europe or Locations Not Listed:
Freescale Semiconductor, Inc.
Technical Information Center, EL516
2100 East Elliot Road
Tempe, Arizona 85284
+1-800-521-6274 or +1-480-768-2130
www.freescale.com/support
Europe, Middle East, and Africa:
Freescale Halbleiter Deutschland GmbH
Technical Information Center
Schatzbogen 7
81829 Muenchen, Germany
+44 1296 380 456 (English)
+46 8 52200080 (English)
+49 89 92103 559 (German)
+33 1 69 35 48 48 (French)
www.freescale.com/support
Japan:
Freescale Semiconductor Japan Ltd.
Headquarters
ARCO Tower 15F
1-8-1, Shimo-Meguro, Meguro-ku,
Tokyo 153-0064
Japan
0120 191014 or +81 3 5437 9125
support.japan@freescale.com
Asia/Pacific:
Freescale Semiconductor Hong Kong Ltd.
Technical Information Center
2 Dai King Street
Tai Po Industrial Estate
Tai Po, N.T., Hong Kong
+800 2666 8080
support.asia@freescale.com
For Literature Requests Only:
Freescale Semiconductor Literature Distribution Center
P.O. Box 5405
Denver, Colorado 80217
1-800-441-2447 or 303-675-2140
Fax: 303-675-2150
LDCForFreescaleSemiconductor@hibbertgroup.com
ESTARRM
Rev. 0
02/2007
RoHS-compliant and/or Pb-free versions of Freescale products have the functionality
and electrical characteristics of their non-RoHS-compliant and/or non-Pb-free
counterparts. For further information, see http://www.freescale.com or contact your
Freescale sales representative.
For information on Freescale’s Environmental Products program, go to
http://www.freescale.com/epp.
Information in this document is provided solely to enable system and software
implementers to use Freescale Semiconductor products. There are no express or
implied copyright licenses granted hereunder to design or fabricate any integrated
circuits or integrated circuits based on the information in this document.
Freescale Semiconductor reserves the right to make changes without further notice to
any products herein. Freescale Semiconductor makes no warranty, representation or
guarantee regarding the suitability of its products for any particular purpose, nor does
Freescale Semiconductor assume any liability arising out of the application or use of any
product or circuit, and specifically disclaims any and all liability, including without
limitation consequential or incidental damages. “Typical” parameters that may be
provided in Freescale Semiconductor data sheets and/or specifications can and do vary
in different applications and actual performance may vary over time. All operating
parameters, including “Typicals”, must be validated for each customer application by
customer’s technical experts. Freescale Semiconductor does not convey any license
under its patent rights nor the rights of others. Freescale Semiconductor products are
not designed, intended, or authorized for use as components in systems intended for
surgical implant into the body, or other applications intended to support or sustain life,
or for any other application in which the failure of the Freescale Semiconductor product
could create a situation where personal injury or death may occur. Should Buyer
purchase or use Freescale Semiconductor products for any such unintended or
unauthorized application, Buyer shall indemnify and hold Freescale Semiconductor and
its officers, employees, subsidiaries, affiliates, and distributors harmless against all
claims, costs, damages, and expenses, and reasonable attorney fees arising out of,
directly or indirectly, any claim of personal injury or death associated with such
unintended or unauthorized use, even if such claim alleges that Freescale
Semiconductor was negligent regarding the design or manufacture of the part.
Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc.
All other product or service names are the property of their respective owners.
© Freescale Semiconductor, Inc. 2007. All rights reserved.