ZHCS290G September   2009  – June 2018 TCA8418

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用范围
  3. 3 说明
    1.     Device Images
      1.      简化原理图
  4. 4 修订历史记录
  5. 5 Pin Configuration and Functions
    1.     Pin 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  Reset Timing Requirements
    8. 6.8  Switching Characteristics
    9. 6.9  Keypad Switching Characteristics
    10. 6.10 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 Key Events
        1. 8.3.1.1 Key Event Table
        2. 8.3.1.2 General Purpose Input (GPI) Events
        3. 8.3.1.3 Key Event (FIFO) Reading
        4. 8.3.1.4 Key Event Overflow
      2. 8.3.2 Keypad Lock/Unlock
      3. 8.3.3 Keypad Lock Interrupt Mask Timer
      4. 8.3.4 Control-Alt-Delete Support
      5. 8.3.5 Interrupt Output
        1. 8.3.5.1 50 Micro-second Interrupt Configuration
    4. 8.4 Device Functional Modes
      1. 8.4.1 Power-On Reset (POR)
      2. 8.4.2 Powered (Key Scan Mode)
        1. 8.4.2.1 Idle Key Scan Mode
        2. 8.4.2.2 Active Key Scan Mode
    5. 8.5 Programming
      1. 8.5.1 I2C Interface
      2. 8.5.2 Bus Transactions
        1. 8.5.2.1 Writes
        2. 8.5.2.2 Reads
    6. 8.6 Register Maps
      1. 8.6.1 Device Address
      2. 8.6.2 Control Register and Command Byte
        1. 8.6.2.1  Configuration Register (Address 0x01)
        2. 8.6.2.2  Interrupt Status Register, INT_STAT (Address 0x02)
        3. 8.6.2.3  Key Lock and Event Counter Register, KEY_LCK_EC (Address 0x03)
        4. 8.6.2.4  Key Event Registers (FIFO), KEY_EVENT_A–J (Address 0x04–0x0D)
        5. 8.6.2.5  Keypad Lock1 to Lock2 Timer Register, KP_LCK_TIMER (Address 0x0E)
        6. 8.6.2.6  Unlock1 and Unlock2 Registers, UNLOCK1/2 (Address 0x0F-0x10)
        7. 8.6.2.7  GPIO Interrupt Status Registers, GPIO_INT_STAT1–3 (Address 0x11–0x13)
        8. 8.6.2.8  GPIO Data Status Registers, GPIO_DAT_STAT1–3 (Address 0x14–0x16)
        9. 8.6.2.9  GPIO Data Out Registers, GPIO_DAT_OUT1–3 (Address 0x17–0x19)
        10. 8.6.2.10 GPIO Interrupt Enable Registers, GPIO_INT_EN1–3 (Address 0x1A–0x1C)
        11. 8.6.2.11 Keypad or GPIO Selection Registers, KP_GPIO1–3 (Address 0x1D–0x1F)
        12. 8.6.2.12 GPI Event Mode Registers, GPI_EM1–3 (Address 0x20–0x22)
        13. 8.6.2.13 GPIO Data Direction Registers, GPIO_DIR1–3 (Address 0x23–0x25)
        14. 8.6.2.14 GPIO Edge/Level Detect Registers, GPIO_INT_LVL1–3 (Address 0x26–0x28)
        15. 8.6.2.15 Debounce Disable Registers, DEBOUNCE_DIS1–3 (Address 0x29–0x2B)
        16. 8.6.2.16 GPIO pull-up Disable Register, GPIO_PULL1–3 (Address 0x2C–0x2E)
      3. 8.6.3 CAD Interrupt Errata
        1. 8.6.3.1 Description
        2. 8.6.3.2 System Impact
        3. 8.6.3.3 System Workaround
      4. 8.6.4 Overflow Errata
        1. 8.6.4.1 Description
        2. 8.6.4.2 System Impact
        3. 8.6.4.3 System Workaround
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Ghosting Considerations
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Designing the Hardware Layout
        2. 9.2.2.2 Configuring the Registers
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 接收文档更新通知
    2. 12.2 社区资源
    3. 12.3 商标
    4. 12.4 静电放电警告
    5. 12.5 术语表
  13. 13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

8.5.2.2 Reads

Reading from a slave is very similar to writing, but requires some additional steps. In order to read from a slave, the master must first instruct the slave which register it wishes to read from. This is done by the master starting off the transmission in a similar fashion as the write, by sending the address with the R/W bit equal to 0 (signifying a write), followed by the register address it wishes to read from. Once the slave acknowledges this register address, the master will send a START condition again, followed by the slave address with the R/W bit set to 1 (signifying a read). This time, the slave will acknowledge the read request, and the master will release the SDA bus but will continue supplying the clock to the slave. During this part of the transaction, the master will become the master-receiver, and the slave will become the slave-transmitter.

The master will continue to send out the clock pulses, but will release the SDA line so that the slave can transmit data. At the end of every byte of data, the master will send an ACK to the slave, letting the slave know that it is ready for more data. Once the master has received the number of bytes it is expecting, it will send a NACK, signaling to the slave to halt communications and release the bus. The master will follow this up with a STOP condition.

Figure 25 shows an example of reading a single byte from a slave register.

TCA8418 i2c_read_example.gifFigure 25. Read from Register