ZHCSJJ3E July   2009  – April 2019 TCA9555

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      简化原理图
  4. 4 修订历史记录
  5. 5 说明 （续）
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 I2C Interface Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 5-V Tolerant I/O Ports
      2. 9.3.2 Hardware Address Pins
      3. 9.3.3 Interrupt (INT) Output
    4. 9.4 Device Functional Modes
      1. 9.4.1 Power-On Reset (POR)
      2. 9.4.2 Powered-Up
    5. 9.5 Programming
      1. 9.5.1 I/O Port
      2. 9.5.2 I2C Interface
        1. 9.5.2.1 Bus Transactions
          1. 9.5.2.1.1 Writes
          2. 9.5.2.1.2 Reads
      3. 9.5.3 Device Address
      4. 9.5.4 Control Register and Command Byte
    6. 9.6 Register Maps
      1. 9.6.1 Register Descriptions
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Calculating Junction Temperature and Power Dissipation
        2. 10.2.2.2 Minimizing ICC When I/O Is Used to Control LED
        3. 10.2.2.3 Pull-Up Resistor Calculation
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13器件和文档支持
    1. 13.1 文档支持
      1. 13.1.1 相关文档
    2. 13.2 接收文档更新通知
    3. 13.3 社区资源
    4. 13.4 商标
    5. 13.5 静电放电警告
    6. 13.6 术语表
  14. 14机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

9.5.2 I2C Interface

The TCA9555 has a standard bidirectional I2C interface that is controlled by a master device in order to be configured or read the status of this device. Each slave on the I2C bus has a specific device address to differentiate between other slave devices that are on the same I2C bus. Many slave devices require configuration upon startup to set the behavior of the device. This is typically done when the master accesses internal register maps of the slave, which have unique register addresses. A device can have one or multiple registers where data is stored, written, or read. For more information see the Understanding the I2C Bus application report, SLVA704.

The physical I2C interface consists of the serial clock (SCL) and serial data (SDA) lines. Both SDA and SCL lines must be connected to VCC through a pull-up resistor. The size of the pull-up resistor is determined by the amount of capacitance on the I2C lines. For further details, refer to I2C Pull-up Resistor Calculation application report, SLVA689. Data transfer may be initiated only when the bus is idle. A bus is considered idle if both SDA and SCL lines are high after a STOP condition.

Figure 24 and Figure 25 show the general procedure for a master to access a slave device:

  1. If a master wants to send data to a slave:
    • Master-transmitter sends a START condition and addresses the slave-receiver.
    • Master-transmitter sends data to slave-receiver.
    • Master-transmitter terminates the transfer with a STOP condition.
  2. If a master wants to receive or read data from a slave:
    • Master-receiver sends a START condition and addresses the slave-transmitter.
    • Master-receiver sends the requested register to read to slave-transmitter.
    • Master-receiver receives data from the slave-transmitter.
    • Master-receiver terminates the transfer with a STOP condition.
TCA9555 I2C_START_STOP.gifFigure 24. Definition of Start and Stop Conditions
TCA9555 I2C_Data_Byte.gifFigure 25. Bit Transfer

Table 1 shows the interface definition.

Table 1. Interface Definition

BYTE BIT
7 (MSB) 6 5 4 3 2 1 0 (LSB)
I2C slave address L H L L A2 A1 A0 R/W
P0x I/O data bus P07 P06 P05 P04 P03 P02 P01 P00
P1x I/O data bus P17 P16 P15 P14 P13 P12 P11 P10