MC3630 Datasheet, PDF (23/83 Pages) –

MC3630 3-Axis Accelerometer
Preliminary Datasheet
4 General Operation
The device supports the reading of samples and device status upon interrupt or via polling. It
contains a 12-bit 32 sample FIFO with programmable watermark. The device is internally
clocked but also includes a manual trigger mode. It can be put into several low power modes,
depending upon the desired sensing application. The device can run in full-featured mode from
its fast internal clock or from a slower heartbeat clock, with limited functionality and at lower
power. The device can connect as a slave to either a SPI or I2C master.
Sensor Sampling
X, Y and Z accelerometer data is stored in registers XOUT, YOUT, and ZOUT registers. The
data is represented as 2’s complement format.
The desired resolution and full scale acceleration range are set in the RANGE_C register.
Offset and Gain Calibration
The default digital offset and gain calibration data can be read from the device, if necessary, in
order to reduce the effects of post-assembly influences and stresses which may cause the
sensor readings to be offset from their factory values.
Reset
Immediate after a power up event, the first transaction can be either I2C or SPI instruction. If
chip select is pull low, the device assumes it is in SPI mode.
The device can be completely reset via an I2C or SPI instruction. Writing 0x1 into register
0x24[6] causes a power-on reset operation to execute. No attempt should be made to access
registers within 1mSec after issuing this operation. The device must be placed in STANDBY
mode before executing the reset. The pin DOUT_A1 is sampled for the purposes of setting the
I2C device address after this reset operation.
NOTE: Immediately after a RESET or power-up event, several registers must be written with
initialization values as shown below. The recommended sequence is:
Step
Address
Value which must be written
Comment
1
0x10
0x01
Go to standby
2
0x24
0x40
Reset (or Power-On)
3
Wait at least 1mSec
Wait for reset to complete
4
0x0D
For SPI: 0x80
For I2C: 0x40
Specify interface
5
0x0F
0x42
Initialization
6
0x20
0x01
Initialization
7
0x21
0x80
Initialization
8
0x28
0x00
Initialization
9
0x1A
0x00
Initialization
10
Configure remaining registers and use sensor as normal
Table 9. Recommended Initialization Sequence
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APS-048-0047v1.2
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