SCPS192E April 2009 – January 2023 TCA6408A
PRODUCTION DATA
Following the successful acknowledgment of the address byte, the bus controller sends a command byte, which is stored in the Control Register in the TCA6408A. Two bits of this data byte will state both 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 I2C bus. The command byte is sent only during a write transmission.
CONTROL REGISTER BITS | COMMAND BYTE (HEX) | REGISTER | PROTOCOL | POWER-UP DEFAULT | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|
B7 | B6 | B5 | B4 | B3 | B2 | B1 | B0 | ||||
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 00 | Input Port | Read byte | xxxx xxxx |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 01 | Output Port | Read/write byte | 1111 1111 |
0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 02 | Polarity Inversion | Read/write byte | 0000 0000 |
0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 03 | Configuration | Read/write byte | 1111 1111 |