
17
Maxim Integrated
Dual Automotive, Audio Line Drivers
with I2C Control and Diagnostic
MAX13325/MAX13326
START and STOP Conditions
A master device initiates communication by issuing
a START condition, which is a high-to-low transition
on SDA with SCL high. A START condition from the
master signals the beginning of a transmission to the
MAX13325/MAX13326. The master terminates transmis-
sion by a STOP condition (see the Acknowledge Bit
section). A STOP condition is a low-to-high transition
on SDA while SCL is high (Figure 3). The STOP condi-
tion frees the bus. If a Repeated START condition is
generated instead of a STOP condition, the bus remains
active. When a STOP condition or incorrect slave ID is
detected, the device internally disconnects SCL from the
serial interface until the next START or Repeated START
condition, minimizing digital noise and feedthrough.
Acknowledge Bit
The acknowledge (ACK) bit is a clocked 9th bit that
the MAX13325/MAX13326 use to handshake receipt of
each byte of data when in write mode. The MAX13325/
MAX13326 pull down SDA during the entire master-
generated 9th clock pulse if the previous byte is suc-
cessfully received (see Figure 4). Monitoring ACK
allows for detection of unsuccessful data transfers. An
unsuccessful data transfer occurs if a receiving device
is busy or if a system fault has occurred. In the event
Figure 3. START/STOP Conditions
Figure 4. Acknowledge and Not-Acknowledge Bits
Table 18. Slave Address
SDA
START
CONDITION
STOP
CONDITION
SCL
SDA
S
SCL
18
NOT ACKNOWLEDGE
ACKNOWLEDGE
9
ADD1
ADD0
A6
A5
A4
A3
A2
A1
A0
R/W
SLAVE
ADDRESS
READ
(HEX)
SLAVE
ADDRESS
WRITE
(HEX)
MODE
GND
—
Stand-
alone
VL
GND
1
0
1
1/0
0xC3
0xC2
I2C
GND
VL
1
0
1
0
1/0
0xC5
0xC4
I2C
VL
1
0
1
1/0
0xC7
0xC6
I2C
SCL
VL
1
0
1
0
1/0
0xC9
0xC8
I2C
SDA
VL
1
0
1
0
1
1/0
0xCB
0xCA
I2C
VL
SCL
1
0
1
0
1/0
0xCD
0xCC
I2C
VL
SDA
1
0
1
1/0
0xCF
0xCE
I2C