SNLA417 January   2023 DP83TC812R-Q1 , DP83TC812S-Q1

 

  1.   Abstract
  2. 1Introduction
    1. 1.1 Acronyms
  3. 2TC10 Test Setup
    1. 2.1 Overview
    2. 2.2 Wakeup to Linking Sequence
  4. 3Measurement Summary
    1. 3.1 Complete Timing Diagram
    2. 3.2 Measurement Summary
    3. 3.3 LP1 Wake to Linking Time
  5. 4Timing Measurements
    1. 4.1 LP1 WAKE to INH (T1)
    2. 4.2 LP1 INH to WUP (T2)
    3. 4.3 WUP to PHY INH (T3)
    4. 4.4 PHY INH/Buck EN to Buck nRESET (T4)
    5. 4.5 Buck nRESET/PMIC Enable to MCU nReset (T5)
    6. 4.6 MCU nReset to MDIO Communication (T6 and T7)
    7. 4.7 MDIO Master Configuration + Linking (T8 and T9)
  6. 5Measurement Evaluation
    1. 5.1 Recommendations for Optimizing Variable TC10 Times
      1. 5.1.1 Improving MCU Boot-up Time (T6)
      2. 5.1.2 Improving MDIO State Machine (T7)
      3. 5.1.3 Optimizing MDIO Timeline (T8)
        1. 5.1.3.1 Optimizing Master Configuration by Removing Polling
        2. 5.1.3.2 Optimizing Master Configuration by Improving MDC
      4. 5.1.4 PHY Configuration During Sleep
      5. 5.1.5 Other Configurable Values
    2. 5.2 Alternative TC10 Test
  7. 6Conclusion
  8. 7References

5.1.4 PHY Configuration During Sleep

Currently, the DP83TC812-Q1 always performs a hard reset after waking up from TC10 sleep so all the registers return to their default state.

The next generation 100BASET1 TI PHY features configuration of up to 20 registers immediately upon waking from sleep mode. This means that interval T7 and T8 are ignored entirely and the PHY can initiate link up with a link partner without waiting for configuration by the MCU. The sequence of events is shown in the following list:

  1. Board MCU programs a list of register address + content in the PHY before the PHY goes to sleep mode
  2. PHY goes to TC10 sleep mode
  3. PHY receives WUP, driving INH HIGH and beginning the wake-up sequence as detailed in Section 2.2
  4. PHY automatically configures the stored register addresses + content from retained memory
  5. PHY initiates link up with a link partner