MC3635 Accelerometer Driver
Quick Start Guide and Demo
GENERAL DESCRIPTION
The MC3635 is an ultra-low power, low
noise, integrated digital output 3-axis
accelerometer with a feature set optimized
for wearables and the Internet of Moving
Things (IoMT) devices. With its low power
modes and tiny footprint this accelerometer
extends sensor battery life and reduces the
space required for the sensor by up to 3X.
Low noise and low power are inherent in
the monolithic fabrication approach.
The EV3635A is a prebuilt circuit board with
the MC3635 accelerometer sensor, with an
internal sample rate from 14 to 1300
samples/second. It measures acceleration
with a wide usage range, from +/-2g up to
+/-16g. It offers 8-bit to 14-bit high-precision
ADC output which is easy mounted onto a
microcontroller platform, such as Arduino.
The accelerometer communicates via I2C
(or SPI) and gives out motion detection or
sample acquisition conditions to trigger an
interrupt toward a MCU.
Sensor data is easily read by simply
connecting DVDD to 3.3V, GND to ground,
and SPI (DOUT, SCK, SCL) pins to your
Arduino SPI (MISO, MOSI, CLK)
respectively. Download the MC3635 library
from mCube’s website onto the board, run
the example sketch, and then sensor data
shortly comes out in raw data count and SI
unit accelerometer measurements.
MC3635 FEATURES
Range, Sampling & Power
±2,4,8,12 or 16g ranges
8, 10 or 12-bit resolution with FIFO
o
14-bit single samples
14 - 1300 samples/sec
o
Sample trigger via internal
oscillator, clock pin or software
command
Sniff and Wake Modes
o
0.4 μA Sniff current @ 6Hz
Ultra-Low Power with FIFO
o
0.9 μA typical current @ 25Hz
o
1.6 μA typical current @ 50Hz
o
2.8 μA typical current @ 100Hz
o
36 μA typical current @ 1300Hz
I2C interface, up to 1 MHz
SPI Interface, up to 4 MHz
1.6 × 1.6 × 0.94 mm 12-pin package
Single-chip 3D silicon MEMS
Low noise down to 2.3mgRMS
Simple System Integration
mCube Proprietary.
© 2016 mCube Inc. All rights reserved.
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MC3635 Accelerometer Driver
Quick Start Guide and Demo
TABLE OF CONTENTS
1
1.1
1.2
1.3
1.4
1.5
General Operation ........................................................................................................... 3
PINOUTS ............................................................................................................................. 3
POWER PINS ...................................................................................................................... 3
SPI PINS .............................................................................................................................. 4
I2C PINS .............................................................................................................................. 4
INTERRUPT PINS ............................................................................................................... 5
2
3
3.1
3.2
ASSEMBLY AND TEST ................................................................................................... 6
DEMO .............................................................................................................................. 7
DOWNLOAD THE DRIVER FROM GITHUB ........................................................................ 7
LOAD THE DEMO ............................................................................................................... 7
4
4.1
4.2
4.3
4.4
4.5
4.6
LIBRARY REFERENCE ................................................................................................ 10
CREATE MCUBE_MC3635 OBJECT ................................................................................ 10
INITIALIZE AND CONFIGURE SENSOR ........................................................................... 10
SET RANGE ...................................................................................................................... 10
READ RANGE ................................................................................................................... 10
READ RESOLUTION ......................................................................................................... 10
READ RAW COUNT DATA ................................................................................................ 10
5
5.1
5.2
DOWNLOADS ............................................................................................................... 11
MC3635 ACCELEROMETER DATASHEET ...................................................................... 11
ALL OTHER MCUBE DOCUMENTATION ......................................................................... 11
6
7
8
9
SCHEMATICS ............................................................................................................... 12
ASSEMBLY DRAWING ................................................................................................. 14
REVISION HISTORY ..................................................................................................... 15
LEGAL ........................................................................................................................... 16
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MC3635 Accelerometer Driver
Quick Start Guide and Demo
1 GENERAL OPERATION
1.1 PINOUTS
Diagram View from front
Labels on back of device (note: pins are
flipped because view is of the back)
Note: for normal use, the current measurement jumper should we closed. Otherwise, it can be
used to measure current. Please refer to Section 2.1 for more information on current
measurement tests.
1.2 POWER PINS
DVDD
– 1.8V/3.3V Power Supply Input
GND
– Ground Pin for Power and Logic
For use with an Arduino, a small modification must be made to the Arduino for it to output at a
3.3V level. By default, Arduinos operate at 5V, which is higher than the maximum voltage
rating for the MC3635 at 3.7V.
An excellent tutorial on modifying an Arduino for use at 3.3V is located at:
https://learn.adafruit.com/arduino-tips-tricks-and-techniques/3-3v-conversion
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MC3635 Accelerometer Driver
Quick Start Guide and Demo
1.3 SPI PINS
To setup using the SPI protocol, connect the following pins. Note that factory preset
configuration of the EV3635A evaluation board is for SPI; no additional rework is required to
start communicating with the device. See Section 7 for more information.
Connect the
SCL
(I2C clock pin) to your microcontroller’s SPI clock line.
Connect the
SDA
(I2C data pin) to your microcontroller’s SPI MOSI line.
Connect the
SDO
SPI pin to your microcontroller’s SPI MISO line
Connect the
CSN
SPI pin to your microcontroller’s CSN SPI line
Use SPI Mode : CPOL = 1, CPHA = 1, MSB first.
1.4 I2C PINS
To setup using the I2C protocol, connect the following pins. Note that factory preset
configuration of the EV3635A evaluation board is for SPI, not I2C. To reconfigure for I2C,
rework is needed. See Section 7 for more information.
Connect the
SCL
(I2C clock pin) to your microcontroller’s I2C clock line.
Connect the
SDA
(I2C data pin) to your microcontroller’s I2C data line.
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MC3635 Accelerometer Driver
Quick Start Guide and Demo
NOTE:
DO NOT install more than one setup pull-up resistors per I2C bus.
1.5 INTERRUPT PINS
INTn
- HW interrupt signal pin. It will be driven by the chip when data is ready to read, or
a motion event is detected by the accelerometer. (Not currently supported in the library
for the interrupt pin, so please check the datasheet for the commands toward related
registers).
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