• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 33 subscribers
  • Views 181 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DS320PR810: How long can start the I2C communication when the system power-on?

Bruce Dai
Intellectual 620 points
Part Number: DS320PR810

Tool/software:

Hi AE,

        We need to write the relevant EQ values via I2C.

        How long should we wait after power-on before proceeding with the write operation?

Best Regards

  • +1
    TI__Mastermind 20901 points

    Hi Bruce,

    The suggestion for programming redriver EQ settings via I2C is for the programming operations to occur before PCIe link training begins - which would be before the de-assertion of PCIe Reset (PERST#). This would allow for all PCIe Link Equalization to occur without electrical changes from the redriver's gain stages.

    Best,
    David

  • +1 in reply to David Waier
    TI__Mastermind 20901 points

    To add a bit of clarity - please refer to TPOR in data sheet Section 6.7: SMBUS/I2C Timing Charateristics for the typical time to first SMBus access after power stable and Power-on-Reset.

    Best,
    David

  • 0
    Intellectual 620 points

    Hi David,

                   Thanks for your great support, but I have some questions to ask you.

                   1. If RD fails to write before PCIe RESET, is it feasible to write before PCIe Link Training?

                   2. What impact would this have?

                   

                    3. Does it require waiting 50ms in both Secondary and EEPROM modes?

                    

    Best Regards

  • 0 in reply to Bruce Dai
    TI__Mastermind 20901 points

    Hi Bruce,

    1. The redriver configuration should be performed prior to PCIe Link Training. This is because the PCIe link will train based on the current link's state, which would be affected by the redriver's equalization settings.
    2. This could impact PCIe link training and link-up performance.
    3. Let me check on this question and get back to you.

    Best,
    David