PNI RM3100 Sensor Suite - Manual (Page 42)

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RM3100 & RM2100 Sensor Suite User Manual Page 41 of 45
Once the measurement sequence is completed on all desired axes, the DRDY pin
is set HIGH and the MISO pin goes low, indicating data is read. The MagI2C is
placed in Idle Mode.
When the host is ready to read the measured values, set SSN to LOW. If SSN
already is LOW, then toggle SSN from LOW to HIGH to LOW.
Assuming the X axis was one of the axes to be measured, send the MX2 Read
address, 0xA4, to begin reading the Measurement Results registers. The
measurement readings will now clock out, with the 3 bytes of X-axis data
presented first, then Y-axis data, then Z-axis data. The first nine (9) bytes
represent a complete 3-axis measurement.
Return SSN to HIGH to free up the host to communicate with other devices and
to ensure the next Command Byte sent to the MagI2C is interpreted properly.
5.8 Examples using the I
2
C Interface
5.8.1 Set the Cycle Count Registers
A sample command sequence is provided below which sets the cycle count value to 100
D
(64
H
) for all 3 axes. This is for illustrative purposes and the value could be different
and/or the number of axes to be addressed could be different. Note only the initial Cycle
Count register address needs to be sent, as the MagI2C automatically increments to the
next register.
START MagI2C ADDRESS RW ACK CCX1 REG. ADDRESS (N) ACK DATA TO CCX1 REG (N) ACK DATA TO CCX0 REG (N+1) ACK
S 0 1 0 0 0 X X 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 1 0 0 0
From Host to MagI2C
From MagI2C to Host
DATA TO CCY1 REG (N+2) ACK DATA TO CCY0 REG (N+3) ACK DATA TO CCZ1 REG (N+4) ACK DATA TO CCZ0 REG (N+5) ACK STOP
0 0 0 0 0 0 0 0 0 0 1 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 1 0 0 0 P