Datasheet
ADAU1761
Rev. C | Page 39 of 92
The R/
W
bit determines the direction of the data. A Logic 0 on
the LSB of the first byte means that the master will write infor-
mation to the peripheral, whereas a Logic 1 means that the
master will read information from the peripheral after writing
the subaddress and repeating the start address. A data transfer
takes place until a stop condition is encountered. A stop
condition occurs when SDA transitions from low to high while
SCL is held high. shows the timing of an I
2
C write,
and shows an I
2
C read.
Figure 49
Figure 50
Stop and start conditions can be detected at any stage during the
data transfer. If these conditions are asserted out of sequence with
normal read and write operations, the ADAU1761 immediately
jumps to the idle condition. During a given SCL high period,
the user should only issue one start condition, one stop condition,
or a single stop condition followed by a single start condition. If
an invalid subaddress is issued by the user, the ADAU1761 does
not issue an acknowledge and returns to the idle condition.
If the user exceeds the highest subaddress while in autoincrement
mode, one of two actions is taken. In read mode, the ADAU1761
outputs the highest subaddress register contents until the master
device issues a no acknowledge, indicating the end of a read. A
no acknowledge condition is where the SDA line is not pulled
low on the ninth clock pulse on SCL. If the highest subaddress
location is reached while in write mode, the data for the invalid
byte is not loaded into any subaddress register, a no acknowledge
is issued by the ADAU1761, and the part returns to the idle
condition.
R/W
0
SCL
SDA
SDA
(CONTINUED)
SCL
(CONTINUED)
111
ADDR0ADDR1
0
START BY
MASTER
FRAME 1
CHIP ADDRESS BYTE
FRAME 2
SUBADDRESS BYTE 1
FRAME 3
SUBADDRESS BYTE 2
FRAME 4
DATA BYTE 1
ACK BY
ADAU1761
ACK BY
ADAU1761
ACK BY
ADAU1761
ACK BY
ADAU1761
STOP BY
MASTER
07680-032
Figure 49. I
2
C Write to ADAU1761 Clocking
R/W
SCL
SDA
SDA
(CONTINUED)
SCL
(CONTINUED)
SDA
(CONTINUED)
SCL
(CONTINUED)
START BY
MASTER
FRAME 2
SUBADDRESS BYTE 1
FRAME 3
SUBADDRESS BYTE 2
FRAME 4
CHIP ADDRESS BYTE
FRAME 1
CHIP ADDRESS BYTE
FRAME 5
READ DATA BYTE 1
ACK BY
ADAU1761
ACK BY
ADAU1761
ACK BY
ADAU1761
ACK BY
ADAU1761
STOP BY
MASTER
ACK BY
MASTER
REPEATED
START BY MASTER
R/W
0
7680-033
ADDR0
ADDR0ADDR1
ADDR1
0111
0
0111
0
Figure 50. I
2
C Read from ADAU1761 Clocking