CS4349
MAP or the default address (see
if an I²C read is the first operation performed on the
device.
3. Once the device has transmitted the contents of the register pointed to by the MAP, issue an ACK.
4. If the INCR bit is set to 1, the device will continue to transmit the contents of successive registers.
Continue providing a clock and issue an ACK after each byte until all the desired registers are read;
then initiate a STOP condition to the bus.
5. If the INCR bit is set to 0 and further I²C reads from other registers are desired, it is necessary to
initiate a repeated START condition and follow the procedure detailed from steps 1 and 2 from the I²C
Write instructions, followed by step 1 of the I²C Read section. If no further reads from other registers
are desired, initiate a STOP condition to the bus.
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18
19
24 25 26 27 28
SCL
CHIP ADDRESS
MAP BYTE
INC 6
ACK
START
5
4
3
2
1
0
ACK
7
DATA
6
1
0
7
DATA +1
6
1
0
7
DATA +n
6
1
0
SDA
1 0 0 1 0 AD1 AD0 R/W
ACK
ACK
STOP
Figure 18. Control Port Timing, I²C Mode
6.3
SPI Mode
In SPI Mode, data is clocked into the serial control data line, CDIN, by the serial control port clock, CCLK
(see
for the clock to data relationship). There are no AD0 or AD1 pins. Pin CS is the chip select
signal and is used to control SPI writes to the control port. When the device detects a high-to-low transition
on the AD0/CS pin after power-up, SPI Mode will be selected. All signals are inputs and data is clocked in
on the rising edge of CCLK.
6.3.1
SPI Write
To write to the device, follow the procedure below while adhering to the control port switching specifica-
tions in
1. Bring CS low.
2. The address byte on the CDIN pin must then be 10011110 (R/W = 0).
3. Write to the memory address pointer, MAP. This byte points to the register to be written.
4. Write the desired data to the register pointed to by the MAP.
5. If the INCR bit (see
is set to 1, repeat the previous step until all the desired registers are
written, then bring CS high.
6. If the INCR bit is set to 0 and further SPI writes to other registers are desired, it is necessary to bring
CS high, and follow the procedure detailed from step 1. If no further writes to other registers are
desired, bring CS high
26
DS782F1
CIRRUS [ CIRRUS LOGIC ]
