SDAA315 March   2026 AM2432 , AM625 , AM62A7 , AM62D-Q1 , AM62L , AM62P , AM6442

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
  5. 2 Terminology
  6. 3 PHY Tuning Algorithm
  7. 4 Key Tuning Parameters
    1. 4.1 Parameter Configurations for Non-DQS PHY Tuning Algorithm
    2. 4.2 Parameter Configurations for DQS PHY Tuning Algorithm
  8. 5 Prerequisites for PHY Tuning Algorithm
    1. 5.1 Hardware Requirements
      1. 5.1.1 Flash Device Preparation
      2. 5.1.2 PHY Configuration
    2. 5.2 Attack Vector
    3. 5.3 Passing vs Failing Region
    4. 5.4 Master vs Bypass Mode
      1. 5.4.1 Bypass Mode
      2. 5.4.2 Master Mode
  9. 6 Need for a Newer Tuning Algorithm
    1. 6.1 Temperature Variations
  10. 7 Algorithm Implementation
    1. 7.1 DQS PHY Tuning Algorithm
      1. 7.1.1 Diagonal Selection
      2. 7.1.2 Valid Read Delays Selection
      3. 7.1.3 Corner Points Identification
        1. 7.1.3.1 Corner Point Selection for Only One Read Delay Value
        2. 7.1.3.2 Corner Point Selection for Two Different Read Delay Values
      4. 7.1.4 Tuning Point Selection
    2. 7.2 Non - DQS PHY Tuning Algorithm
      1. 7.2.1 Fix Tx DLL Value
      2. 7.2.2 Find Rx Window 1
      3. 7.2.3 Find Rx Window 2
      4. 7.2.4 Choose Larger Rx Window
      5. 7.2.5 Calculate the OTP
      6. 7.2.6 Temperature Consideration
  11. 8 Tuning Enhancements
    1. 8.1 Tuning Time Optimization – Skip Tuning Feature
    2. 8.2 Runtime Validation – Validate OTP
  12. 9 Summary
  13. 10References

7.1.4 Tuning Point Selection

The algorithm selects the region with larger length and calculates the midpoint (midpoint1). Corner points of a line perpendicular to the diagonal at midpoint1 are identified, representing consecutive passing points. The midpoint of the perpendicular line (midpoint2) is calculated, representing the center width of the stable region. Radius verification tests whether all points within a circle of specified radius around midpoint2 pass. If successful, midpoint2 becomes the optimal tuning point.

Tuning Point Selection at MidpointFigure 7-6 Tuning Point Selection at Midpoint

If radius verification fails, the perpendicular line is divided into two segments at midpoint1. The midpoint of the larger segment (midpoint3) undergoes radius verification. If successful, midpoint3 becomes the tuning point.

Tuning Point Selection at Midpoint of Larger SegmentFigure 7-7 Tuning Point Selection at Midpoint of Larger Segment

If both midpoint2 and midpoint3 fail, the second read delay region is evaluated if the length exceeds minimum pass length, repeating the selection process.

If all regions and segments fail, the algorithm reports tuning failure and selects a different diagonal, following a predefined pattern to enable comprehensive coverage. Each diagonal represents different delay parameter

combinations, offering multiple opportunities to find a stable operating region.

In case of PHY failures, see the PHY Failure section in the Common Bring-up Issues and Debugging Application Note.

Flowchart of DQS Tuning AlgorithmFigure 7-8 Flowchart of DQS Tuning Algorithm