SDAA032 July   2025 TDA4VE-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Understanding PWM Operation on TDA4x
    1. 2.1 PWM Architecture Overview
    2. 2.2 Counter-Compare Register and Duty Cycle Control
    3. 2.3 Action Qualifier and Output Behavior
    4. 2.4 Synchronization and Update Timing
  6. 3Unintended PWM Duty Cycle from Immediate CMPA Update
  7. 4Unintended PWM Duty Cycle from Up-Down Count Mode
  8. 5Best Practice for Seamless PWM Updates for LED Dimming Control
    1. 5.1 Use Shadow Registers for Duty Cycle Updates
    2. 5.2 Select the Appropriate Counter Mode
    3. 5.3 Register Configurations for Up-count Mode Under Shadowing
  9. 6Summary
  10. 7References

5.1 Use Shadow Registers for Duty Cycle Updates

Always enable shadow loading of CMPA compare register to defer updates until the start or end of the PWM period by configuring EPWM_CMPCTL.LOADAMODE = 0, and this makes sure the CMPA register is updated deterministically at a specific event such as TBCNT = 0 or TBCNT = TBPRD.