CM6327A
USB Single-Chip Audio Solution for Mono Microphone
During the write transfer, the MCU continues acting as the master, and the transfer direction is not changed.
The following figure gives an example of one byte write transfer.
MCU write:
S
0x70
0
addr
0
Byte 0
0
Byte 1
0
….
0
Byte N
0
P
From CM6327A to MCU
START condition
From MCU to CM6327A
STOP condition
S
0
P
1
Positive acknowledge
Negative acknowledge
Byte N
One byte data
The CM6327A’s slave address is 0x70, which will also tell the CM6327A when it’s receiving a write command.
CM6327A regards the first coming data byte as the register address. The second data byte is the data
content that the MCU writes at the register address. The CM6327A will auto-increment the register address
to the next register address for the following data writes.
The figure below shows an example of a read transfer. The MCU read command cannot set the register
address, so the MCU must use a write command to set the register address first, and then start the read
command. Because the CM6327A auto-increments the register address, the second data byte will be the
register data on the next address.
MCU read:
S
S
0x70
0x71
0
0
addr
0
0
Byte 0
Byte 1
0
…..
0
Byte N
1
P
From CM6327A to MCU
START condition
From MCU to CM6327A
STOP condition
S
0
P
1
Positive acknowledge
Negative acknowledge
Byte n One byte of data
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