ZHCSQD1 August   2022 DS320PR810

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  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 DC Electrical Characteristics
    6. 6.6 High Speed Electrical Characteristics
    7. 6.7 SMBUS/I2C Timing Charateristics
    8. 6.8 Typical Characteristics
    9. 6.9 Typical Jitter Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Linear Equalization
      2. 7.3.2 Flat-Gain
      3. 7.3.3 Receiver Detect State Machine
    4. 7.4 Device Functional Modes
      1. 7.4.1 Active PCIe Mode
      2. 7.4.2 Active Buffer Mode
      3. 7.4.3 Standby Mode
    5. 7.5 Programming
      1. 7.5.1 Pin mode
        1. 7.5.1.1 Five-Level Control Inputs
      2. 7.5.2 SMBUS/I2C Register Control Interface
        1. 7.5.2.1 Shared Registers
        2. 7.5.2.2 Channel Registers
      3. 7.5.3 SMBus/I 2 C Primary Mode Configuration (EEPROM Self Load)
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 PCIe Reach Extension – x16 Lane Configuration
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 接收文档更新通知
    2. 11.2 支持资源
    3. 11.3 Trademarks
    4. 11.4 静电放电警告
    5. 11.5 术语表
  12. 12Mechanical, Packaging, and Orderable Information

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7.5.3 SMBus/I2C Primary Mode Configuration (EEPROM Self Load)

The DS320PR810 can also be configured by reading from EEPROM. To enter into this mode MODE pin must be set to L1. The EEPROM load operation only happens once after the device's initial power-up. If the DS320PR810 is configured for SMBus Primary mode, then it will remain in the SMBus IDLE state until the READ_EN_N pin is asserted to LOW. After the READ_EN_N pin is driven LOW, the DS320PR810 becomes an SMBus primary and attempts to self-configure by reading the device settings stored in an external EEPROM (SMBus 8-bit address 0xA0). When the DS320PR810 has finished reading from the EEPROM successfully, it will drive the ALL_DONE_N pin LOW. SMBus/I2C secondary operation is available in this mode before, during, or after EEPROM reading. Note: during EEPROM reading, if the external SMBus/I2C primary wants to access DS320PR810 registers, then it must support arbitration.

When designing a system for using the external EEPROM, the user must follow these specific guidelines:

  • EEPROM size of 2 kb (256 × 8-bit) is recommended.
  • Set MODE = L1, configure for SMBus Primary mode.
  • The external EEPROM device address byte must be 0xA0 and capable of 400 kHz operation at 3.3 V supply
  • In SMBus/I2C modes the SCL and SDA pins must be pulled up to a 3.3 V supply with a pull-up resistor. The value of the resistor depends on total bus capacitance. 4.7 kΩ is a good first approximation for a bus capacitance of 10 pF.

Figure 7-1 shows a use case with four DS320PR810 to implement a PCIe x16 configuration, but the user can cascade any number of DS320PR810 devices in a similar way. Tie the READ_EN_N pin of the first device low to automatically initiate EEPROM read at power up. Alternatively, the READ_EN_N pin of the first device can also be controlled by a micro-controller to initiate the EEPROM read manually. Leave the ALL_DONE_N pin of the final device floating, or connect the pin to a micro-controller input to monitor the completion of the final EEPROM read.

GUID-20210507-CA0I-F2FG-FBDG-9N02R9NGFLMC-low.gif Figure 7-1 Daisy Chain Four DS320PR810 Devices to Read from Single EEPROM in x16 Configuration