SCPS128D July   2006  – March 2021 PCA9554

PRODUCTION DATA  

  1. 1 Features
  2. 2 Description
  3. 3 Revision History
  4. 4 Description (Continued)
  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 I2C Interface Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Functional Block Diagram
    2. 8.2 Device Functional Modes
      1. 8.2.1 Power-On Reset
      2. 8.2.2 I/O Port
      3. 8.2.3 Interrupt Output ( INT)
        1. 8.2.3.1 Interrupt Errata
          1.        23
          2. 8.2.3.1.1 24
          3. 8.2.3.1.2 25
    3. 8.3 Programming
      1. 8.3.1 I2C Interface
      2. 8.3.2 Register Map
        1. 8.3.2.1 Device Address
        2. 8.3.2.2 Control Register And Command Byte
        3. 8.3.2.3 Register Descriptions
        4. 8.3.2.4 Bus Transactions
          1. 8.3.2.4.1 Writes
          2. 8.3.2.4.2 Reads
  9. 9 Application Information Disclaimer
    1. 9.1 Application Information
      1. 9.1.1 Typical Application
        1. 9.1.1.1 Design Requirements
          1. 9.1.1.1.1 Minimizing ICC When I/Os Control Leds
  10. 10Power Supply Recommendations
    1. 10.1 Power-On Reset Requirements
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information
8.3.2.4.2 Reads

The bus master first must send the PCA9554 address with the least-significant bit set to a logic 0 (see Figure 8-6 for device address). The command byte is sent after the address and determines which register is accessed. After a restart, the device address is sent again but, this time, the least-significant bit is set to a logic 1. Data from the register defined by the command byte then is sent by the PCA9554 (see Figure 8-10 and Figure 8-11). After a restart, the value of the register defined by the command byte matches the register being accessed when the restart occurred. Data is clocked into the register on the rising edge of the ACK clock pulse. There is no limitation on the number of data bytes received in one read transmission, but when the final byte is received, the bus master must not acknowledge the data

GUID-3A8A589E-63E9-47BD-A77A-80B69C61778F-low.gifFigure 8-10 Read From Register

GUID-D328DA73-2E7E-4C54-AF9D-0B2FC4873416-low.gif
This figure assumes the command byte has previously been programmed with 00h.
Transfer of data can be stopped at any moment by a Stop condition.
This figure eliminates the command byte transfer, a restart, and slave address call between the initial slave address call and actual data transfer from P port. See Figure 8-10 for these details.
Figure 8-11 Read From Input Port Register