MAX7311 Maxim, MAX7311 Datasheet - Page 8

• Manufacturer Part Number: MAX7311
• Description: The MAX7311 2-wire-interfaced expander provides 16-bit parallel input/output (I/O) port expansion for SMBus™ and I²C applications
• Manufacturer: Maxim

MAX7311 generates the acknowledge bit since the
MAX7311 is the recipient. When the MAX7311 is trans-
mitting to the master, the master generates the
acknowledge bit.
The MAX7311 has a 7-bit-long slave address (Figure 6).
The 8th bit following the 7-bit slave address is the R/W
bit. Set this bit low for a write command and high for a
read command.
2-Wire-Interfaced 16-Bit I/O Port Expander
with Interrupt and Hot-Insertion Protection
Figure 6. Slave Address
Table 1. Command Byte Register
Figure 7. Writes to Output Registers Through Write Byte Protocol
8
_______________________________________________________________________________________
COMMAND BYTE
SDA
SDA
ADDRESS (HEX)
SCL
SDA
MSB
A6
CONDITION
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
0xFF
START
WRITE TO PORT
DATA OUT PORT 1
READ FROM PORT 2
S
A5
1
2
SLAVE ADDRESS
A4
PROGRAMMABLE
3
4
A3
5
R/W
Input port 1
Input port 2
Output port 1
Output port 2
Port 1 polarity inversion
Port 2 polarity inversion
Port 1 configuration
Port 2 configuration
Timeout register
Factory reserved. (Do not write to this register.)
6
A2
7
ACKNOWLEDGE
8
FROM SLAVE
A1
9
A
0
LSB
Slave Address
A0
0
COMMAND BYTE
0
FUNCTION
R/W
0
0
ACK
0
1
ACKNOWLEDGE
FROM SLAVE
0 A
7
6
Slave address pins AD2, AD1, and AD0 choose 1 of 64
slave ID addresses (Table 7).
The command byte is the first byte to follow the 8-bit
device slave address during a write transmission
(Table 1, Figure 7). The command byte is used to deter-
mine which of the following registers are written or read.
Transmit data to the MAX7311 by sending the device
slave address and setting the LSB to a logic zero. The
command byte is sent after the address and deter-
mines which registers receive the data following the
command byte (Figure 7).
PORT 1 DATA
5
4
3
2
Read byte
Read byte
Read/write byte
Read/write byte
Read/write byte
Read/write byte
Read/write byte
Read/write byte
Read/write byte
1
ACKNOWLEDGE
0 A
FROM SLAVE
PROTOCOL
7
t
PV
—
6
PORT 2 DATA
5
4
3
Data Bus Transaction
2
Writing to Port Registers
1
ACKNOWLEDGE
0
FROM SLAVE
A
t
PV
POWER-UP
XXXX XXXX
XXXX XXXX
1111 1111
1111 1111
0000 0000
0000 0000
1111 1111
1111 1111
0000 0001
DEFAULT
—