SCPS279 February   2022 TCA9537

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 I2C Bus Timing Requirements
    8. 6.8 Switching Characteristics
    9. 6.9 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 I/O Port
      2. 8.3.2 Interrupt (INT) Output
      3. 8.3.3 RESET Input
    4. 8.4 Device Functional Modes
      1. 8.4.1 Power-On Reset
      2. 8.4.2 Powered-Up
    5. 8.5 Programming
      1. 8.5.1 I2C Interface
        1. 8.5.1.1 Writes
        2. 8.5.1.2 Reads
      2. 8.5.2 Software Reset Call
    6. 8.6 Register Maps
      1. 8.6.1 Device Address
      2. 8.6.2 Control Register and Command Byte
      3. 8.6.3 Register Descriptions
  9. 9 Application Information Disclaimer
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
        1. 9.2.1.1 Minimizing ICC When I/Os Control LEDs
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 Power-On Reset
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.6.2 Control Register and Command Byte

Following the successful acknowledgment of the address byte, the bus controller sends a command byte that is stored in the control register in the TCA9537. This data byte states the operation (read or write) and the internal register (Input, Output, Polarity Inversion, or Configuration) that sre affected. This register can be written or read through the I2C bus. The command byte is sent only during a write transmission.

Once a command byte has been sent, the register that was addressed continues to be accessed by reads until a new command byte has been sent.

Table 8-2 Command Byte
COMMAND BYTE
(HEX)		REGISTERPROTOCOLPOWER-UP
DEFAULT
0x00Input PortRead byte1111 XXXX
0x01Output PortRead/write byte1111 1111
0x02Polarity InversionRead/write byte0000 0000
0x03ConfigurationRead/write byte1111 1111