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

5.1.3.2 Optimizing Master Configuration by Improving MDC

The DP83TC812-Q1 supports an MDC up to 25 MHz. If a MAC interface supports an MDC of 25 MHz, this time can be further optimized as the following equation shows.

Δtms_cfg = 90 instructions × 32 bits × (1/25 MHz) = 0.23ms. This is 3.799ms less than the actual time measured.