ZHCSEZ2D January 2014 – October 2021 TCA9539-Q1
PRODUCTION DATA
- 1 特性
- 2 应用
- 3 说明
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Parameter Measurement Information
- 8 Detailed Description
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
8.6.2 Control Register And Command Byte
Following the successful acknowledgment of the address byte, the bus controller sends a command byte shown in Table 8-3 that is stored in the control register in the TCA9539-Q1. Three bits of this data byte state the operation (read or write) and the internal register (input, output, Polarity Inversion or Configuration) that is affected. This register can be written or read through the I2C bus. The command byte is sent only during a write transmission.
When a command byte has been sent, the register pair that was addressed continues to be accessed by reads until a new command byte has been sent. Figure 8-6 shows the control register bits.
Figure 8-6 Control Register Bits| CONTROL REGISTER BITS | COMMAND BYTE (HEX) | REGISTER | PROTOCOL | POWER-UP DEFAULT | ||
|---|---|---|---|---|---|---|
| B2 | B1 | B0 | ||||
| 0 | 0 | 0 | 0x00 | Input Port 0 | Read byte | xxxx xxxx |
| 0 | 0 | 1 | 0x01 | Input Port 1 | Read byte | xxxx xxxx |
| 0 | 1 | 0 | 0x02 | Output Port 0 | Read-write byte | 1111 1111 |
| 0 | 1 | 1 | 0x03 | Output Port 1 | Read-write byte | 1111 1111 |
| 1 | 0 | 0 | 0x04 | Polarity Inversion Port 0 | Read-write byte | 0000 0000 |
| 1 | 0 | 1 | 0x05 | Polarity Inversion Port 1 | Read-write byte | 0000 0000 |
| 1 | 1 | 0 | 0x06 | Configuration Port 0 | Read-write byte | 1111 1111 |
| 1 | 1 | 1 | 0x07 | Configuration Port 1 | Read-write byte | 1111 1111 |