Datasheet

B2 B1
B0B5
B4
B3
B7
B6
0
Slave Address
1
0 0
0 0
AD
DR
R/W
Fixed
Programmable
TCA6416A
www.ti.com SCPS194A –MAY 2009–REVISED NOVEMBER 2009
Table 4. Interface Definition
BIT
BYTE
7 (MSB) 6 5 4 3 2 1 0 (LSB)
I
2
C slave address L H L L L L ADDR R/W
P07 P06 P05 P04 P03 P02 P01 P00
I/O data bus
P17 P16 P15 P14 P13 P12 P11 P10
Device Address
The address of the TCA6416A is shown in Figure 6.
Figure 6. TCA6416A Address
Table 5. Address Reference
ADDR I
2
C BUS SLAVE ADDRESS
L 32 (decimal), 20 (hexadecimal)
H 33 (decimal), 21 (hexadecimal)
The last bit of the slave address defines the operation (read or write) to be performed. A high (1) selects a read
operation, while a low (0) selects a write operation.
Control Register and Command Byte
Following the successful acknowledgment of the address byte, the bus master sends a command byte, which is
stored in the control register in the TCA6416A. Three bits of this data byte state the operation (read or write) and
the internal registers (input, output, polarity inversion, or configuration) that will be affected. This register can be
written or read through the I
2
C bus. The command byte is sent only during a write transmission.
Once a new command has been sent, the register that was addressed continues to be accessed by reads until a
new command byte has been sent.
Figure 7. Control Register Bits
Table 6. Command Byte
CONTROL REGISTER BITS
COMMAND BYTE POWER-UP
REGISTER PROTOCOL
(HEX) DEFAULT
B7 B6 B5 B4 B3 B2 B1 B0
0 0 0 0 0 0 0 0 00 Input Port 0 Read byte xxxx xxxx
(1)
0 0 0 0 0 0 0 1 01 Input Port 1 Read byte xxxx xxxx
0 0 0 0 0 0 1 0 02 Output Port 0 Read/write byte 1111 1111
0 0 0 0 0 0 1 1 03 Output Port 1 Read/write byte 1111 1111
0 0 0 0 0 1 0 0 04 Polarity Inversion Port 0 Read/write byte 0000 0000
0 0 0 0 0 1 0 1 05 Polarity Inversion Port 1 Read/write byte 0000 0000
0 0 0 0 0 1 1 0 06 Configuration Port 0 Read/write byte 1111 1111
0 0 0 0 0 1 1 1 07 Configuration Port 1 Read/write byte 1111 1111
(1) Undefined
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