Digilent 410-285P - Manual (Page 2)

Digilent PmodCMPS
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Read
A read operation can be initiated with a Start condition on the I
2 C bus, followed by 0x3D. After the PmodCMPS
acknowledges that it has been addressed on the 9 th clock pulse, the data to be read will be output from the
device on the next 8 clock pulses. The data sent will be from the address pointed to by the internal address
pointer. This will have either been automatically incremented from the previous read operation, or set by the
previous write operation.
1. 7-bit address of the PmodCMPS + read bit (1)
2. Master reads data byte sent from PmodCMPS
3. (Loop)
Note
that step three is necessary when reading the 6 axis data registers. The master should read all six data
registers at once.
Set Address Pointer
The address pointer can be set to any register by only completing steps one and two from the write procedure
(listed above). After the PmodCMPS acknowledges the register address, the master should create a Stop
condition on the I
2
C bus.
Note:
For more information on the operation of the PmodCMPS, please see the HMC5883L data sheet
available from www.honeywell.com .