Sensors Fundamentals
Dragos Bogdan, MCU Application Engineer
Analog Devices
Class ID: CL06B
Renesas Electronics America Inc.
© 2012 Renesas Electronics America Inc. All rights reserved.
Dragos Bogdan : MCU Application Engineer
 Dragos holds a BS degree in Applied Electronics and a MS
degree in Advanced Manufacturing Engineering
Management. He has extensive experience in embedded
systems design and implementation both from software and
hardware perspective.
 He has joined ADI in 2011 as MCU Application Engineer. His
current job responsibilities include device drivers design and
implementation and writing technical documentation for ADI
MCU reference designs. He leads the ADI Romania MCU
development team.
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© 2012 Renesas Electronics America Inc. All rights reserved.
Renesas Technology & Solution Portfolio
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Agenda
 Introduction
 Sensors fundamentals
 ADI sensors
 Sensors data acquisition
 ADI support for sensors applications
 Hands on lab
 Summary
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© 2012 Renesas Electronics America Inc. All rights reserved.
Introduction
 The Sensor Fundamentals lab provides an introduction to
some of the ADI sensors and to the evaluation boards for
these sensors compatible with Renesas MCU platforms
 We will show the process of exchanging data with ADI digital
sensors
 We will show the steps required to read data from ADI
analog sensors using the A/D converter incorporated in a
Renesas MCU
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© 2012 Renesas Electronics America Inc. All rights reserved.
Sensors Fundamentals
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What is a Sensor?
 A sensor is a device that receives a signal or a stimulus and
responds with an electrical signal
 Sensors are used to measure various physical properties:
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Temperature
Tilt, inertial forces, shock and vibration - accelerometers
Angular rate (how quickly an object turns) - gyroscopes
Sound intensity - microphones
© 2012 Renesas Electronics America Inc. All rights reserved.
Sensors Classification
 Sensors can be classified according to the physical property
the sensor is designed to measure
 From a signal-conditioning viewpoint, sensors can be
classified as:
 Active sensors – require an external source of excitation.
 Passive sensors – generate their own electric output signal
without requiring external voltages or currents
 From the output electrical signal viewpoint, sensors can be
grouped in two categories:
 Analog sensors – produce analog output
 Digital sensors – provide digital output
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ADI Sensors
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Analog Devices Sensors Product Range
 Analog Devices sensor portfolio focuses on:
 Motion
 Temperature
 Sound
 ADI offers the broadest MEMS (MicroElectroMechanical
Systems) inertial sensor portfolios in the industry, including:
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High performance low-g accelerometers
High-g accelerometers
Gyroscopes
Fully integrated Inertial Measurement Units (IMUs)
High performance MEMS microphones
© 2012 Renesas Electronics America Inc. All rights reserved.
ADI Sensors Evaluation
 ADI offers for most of its products at least one type of evaluation
board. Some boards can be connected directly to PCs using USB or
Serial ports, others to FPGA or MCU development boards using
special connectors
 The ADI evaluation boards compatible and directly connectable to
the Renesas MCU platforms are the Pmods
 Connections between a Renesas MCU other ADI evaluation boards
can be made using wires
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What are the Pmods?
 Small I/O interface boards that offer an ideal way to extend
the capabilities of development boards
 Communicate with system boards using 6 or 12-pin
connectors
 Four main categories
1.
2.
3.
4.
Input / output
Sensor / actuators
Data acquisition and conversion
Connectors
 Complete list at:
www.digilentinc.com/AnalogDevices
3-axis
Accelerometer
 Renesas MCU development boards with
Pmod connectors
 RL78/G13 RDK
 RL78/G14 RDK
 RX63N RDK
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Serial
converter
& interface
Two 12-bit
A/D inputs
ADI Pmods – Data Acquisition and Conversion
PmodAD1 - Two 12-bit A/D
inputs
Analog Devices AD7476
Sampling rate: 1MSPS
Resolution: 12 bit
No. of Channels: 2
Interface: SPI
ADC type: SAR
PmodAD4 – 1 channel 16-bit
A/D converter
Analog Devices AD7980
Sampling rate: 1MSPS
Resolution: 16 bit
No. of Channels: 1
Interface: SPI
ADC type: PULSAR®
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PmodAD2 - 4 channel 12-bit
A/D converter
Analog Devices AD7991
Sampling rate: 1MSPS
Resolution: 12 bit
No. of Channels: 4
Interface: I2C
ADC type: SAR
PmodAD5 - 4 channel 24-bit
A/D converter
Analog Devices AD7193
Sampling rate: 4.8kSPS
Resolution: 24 bit
No. of Channels: 4
Interface: SPI
ADC type: Σ-Δ
ADI Pmods – Data Acquisition and Conversion
PmodAD6 - 1 channel 24-bit
A/D converter
Analog Devices AD7091R
Sampling rate: 1MSPS
Resolution: 12 bit
No. of Channels: 1
Interface: SPI
ADC type: SAR
Ultralow power
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PmodIA – High precision
impedance converter
Analog Devices AD5933
High precision impedance converter
system solution that
combines an on-board
frequency generator
with a 12-bit, 1 MSPS,
A/D converter.
ADI Pmods – Data Acquisition and Conversion
PmodDA1 - 8-bit dual D/A
converter
Analog Devices AD7303
Clock rate: up to 30MHz
Resolution: 8 bit
No. of Channels: 2
Interface: SPI
PmodDA4 – 8 channels 12-bit
D/A converter
Analog Devices AD5628
Clock rate: up to 50MHz
Resolution: 16 bit
No. of Channels: 8
Interface: SPI
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PmodDA3 - 1 channel 16-bit
D/A converter
Analog Devices AD5541A
Clock rate: up to 50MHz
Resolution: 16 bit
No. of Channels: 1
Interface: SPI
PmodPOT – Digital
potentiometer
Analog Devices AD5160
Resolution: 256 positions
Interface: SPI
ADI Pmods – Input / Output
PmodIOXP – I/O Expansion
Module
Analog Devices ADP5589
Functions as an I/O port expander
and keypad matrix decoder
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PmodRS232 – Serial converter
& interface
Analog Devices ADM3232E
Translates voltage from the logic levels
used by system boards to the RS232
voltage
ADI Pmods – Sensors
PmodACL – 3-axis accelerometer
Analog Devices ADP5589
PmodACL2 – 3-axis MEMS
accelerometer
Analog Devices ADXL362
Low power, 3-axis accelerometer with high
resolution (13-bit). Measurement at up to
±16 g. Digital output
data is formatted as
16-bit 2’s complement
and is accessible through
either a SPI or I2C.
Ultralow power, 3-axis MEMS accelerometer.
Consumes less than
2 μA at a 100 Hz output
data rate and 270 nA
when in motion triggered
wake-up mode.
12 bit output resolution.
PmodGYRO2 – Angular rate sensor
(gyroscope)
Analog Devices ADXRS453
PmodTMP2 – High accuracy digital
temperature sensor
Analog Devices ADT7420
Intended for industrial, instrumentation,
and stabilization applications in high
vibration environments.
High accuracy rate sensing
in harsh environments
where shock and vibration
are present.
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Contains an internal band gap reference, a
temperature sensor, and a 16-bit ADC to
monitor and digitize
the temperature to
0.0078°C resolution.
The ADC resolution is
set to 13 bits (0.0625°C)
and can be programmed
through the serial interface.
Sensors Data Acquisition
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Sensors Interfacing With MCUs
 When a sensor has to be interfaced with a microcontroller,
the classification from the output electrical signal viewpoint
is important
 Usually, digital sensors can be connected directly to a
microcontroller through the integrated data peripherals.
Many sensors can be connected to the same peripheral.
 If an analog sensor has to be interfaced, the analog sensor
data has to be digitized. This process can be done with an
A/D converter.
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Sensors Interfacing With MCUs
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I2C Communication
 ADT7420 – Reading back data from the ID register
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SPI Communication
 ADXL345 – Reading back data from the ID register
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Analog Output
 ADMP401 - The output signal amplified by SSM2167
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Digital or Analog?
Digital Sensors
 Can be connected directly to MCU.
 Many sensors can be connected to
the same bus.
 More expensive than analog
sensors.
 Bigger than analog sensors.
 Are built to meet the requirements
of most customers.
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Analog Sensors
 Usually, the analog signal has to be
conditioned to meet the input
requirements of the ADC.
 Each sensor needs an ADC.
 Cheaper than digital sensors.
 Smaller than digital sensors.
 ADC can be chosen to satisfy your
specific sample rate and resolution
requirements.
ADI Support for Sensors Applications
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EZ.Analog.com
 EngineerZone (ez.analog.com) is a technical support forum
from Analog Devices
 It allows you direct access to ADI technical support engineers
 Use it also to connect with other developers who face similar
design challenges
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Wiki.Analog.com
 Complementary site to EZ, the Wiki (wiki.analog.com) is a
collaborative space allowing the sharing of knowledge and
content between ADI engineers and the design engineering
community
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© 2012 Renesas Electronics America Inc. All rights reserved.
Sensors Drivers
 The drivers for a wide list of ADI products can be downloaded from
the Wiki page. The drivers may be used without modifications, with
any microcontroller, but the specific communication functions for
the desired type of processor and communication protocol have to
be implemented.
 For each driver can be downloaded also implementation examples
for different types of processors including the Renesas RL78G13,
Renesas RX62N and Renesas RX63N
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Hands on Lab
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© 2012 Renesas Electronics America Inc. All rights reserved.
Hands on Lab
 During the hands on part of the lab the attendees are guided
through a series of steps required to create a new project for
the selected Renesas MCU, establish communication through
SPI and I2C with different ADI digital sensors, read data
from an ADI analog sensor through the A/D converter found
on the Renesas MCU.
 The data read from the ADI sensors is displayed on the LCD
found on the Renesas RDK thus providing direct feedback
without the need of additional hardware resources. Each
sensor has a separate display page showing the values read
from the sensor and also data graphs where possible.
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© 2012 Renesas Electronics America Inc. All rights reserved.
Summary
 The lab provided an introduction to some of the ADI sensors
and to the evaluation boards for these sensors compatible
with Renesas MCU platforms
 The ADI support websites for sensors applications were
presented:
 wiki.analog.com - reference projects documentation and source
code
 ez.analog.com - technical support forum
 During the lab the attendees learnt how to create a new
project for a Renesas MCU and how to exchange data with
ADI digital and analog sensors
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Questions?
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Please Provide Your Feedback…
 Please utilize the ‘Guidebook’ application to leave feedback
or
 Ask me for the paper feedback form for you to use…
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© 2012 Renesas Electronics America Inc. All rights reserved.
Renesas Electronics America Inc.
© 2012 Renesas Electronics America Inc. All rights reserved.