CS42406
4.10.1a INCR (Auto Map Increment)
The CS42406 has MAP auto increment capability enabled by the INCR bit (the MSB) of the MAP. If INCR
is set to 0, MAP will stay constant for successive I²C writes or reads and SPI writes. If INCR is set to 1,
MAP will auto increment after each byte is written, allowing block reads or writes of successive registers.
Default = ‘0’
0 - Disabled
1 - Enabled
4.10.1b MAP0-3 (Memory Address Pointer)
Default = ‘0000’
4.10.2
I²C Mode
In the I²C mode, data is clocked into and out of the bi-directional serial control data line, SDA, by the serial
control port clock, SCL. There is no CS pin. Pin AD0 enables the user to alter the chip address
(001000[AD0][R/W]) and should be tied to VLC or GND as required, before powering up the device. If the
device ever detects a high to low transition on the AD0/CS pin after power-up, SPI mode will be selected.
4.10.2a I²C Write
To write to the device, follow the procedure below while adhering to the control port timing as described
in “Switching Specifications - Control Port Interface” on page 27.
1) Initiate a START condition to the I²C bus followed by the address byte. The upper 6 bits must be
001000. The seventh bit must match the setting of the AD0 pin, and the eighth must be 0. The eighth
bit of the address byte is the R/W bit.
2) Wait for an acknowledge (ACK) from the part, then write to the memory address pointer, MAP. This
byte points to the register to be written.
3) Wait for an acknowledge (ACK) from the part, then write the desired data to the register pointed to by
the MAP.
4) If the INCR bit (see section 4.10.1a) is set to 1, repeat the previous step until all the desired registers
are written, then initiate a STOP condition to the bus.
5) If the INCR bit is set to 0 and further I²C writes to other registers are desired, it is necessary to repeat
the procedure detailed from step 1. If no further writes to other registers are desired, initiate a STOP
condition to the bus.
DATA
1-8
MAP
1-8
W
ACK
ACK
ACK
001000 AD0
SDA
SCL
Stop
Start
Figure 38. I²C Write
4.10.2b I²C Read
To read from the device, follow the procedure below while adhering to the control port Switching Specifi-
cations. During this operation it is first necessary to write to the device, specifying the appropriate register
through the MAP.
37
CIRRUS [ CIRRUS LOGIC ]
