SPRUHM8K December 2013 – May 2024 TMS320F28374D , TMS320F28375D , TMS320F28376D , TMS320F28377D , TMS320F28377D-EP , TMS320F28377D-Q1 , TMS320F28378D , TMS320F28379D , TMS320F28379D-Q1
To use high-resolution period, the ePWMx module must be initialized in the exact order presented.
The following steps use CMPA with shadow registers and the corresponding HRCNFG bits for high-resolution operation on EPWMxA. For high-resolution operation on EPWMxB, make the appropriate substitutions with the B channel fields.
When high-resolution period mode is enabled, an EPWMxSYNC pulse introduces ±1-2 cycle jitter to the PWM (±1 cycle in up-count mode and ±2 cycle in up-down count mode). For this reason, TBCTL[SYNCOSEL] cannot be set to 1 (CTR = 0 is EPWMxSYNCO source) or 2 (CTR = CMPB is EPWMxSYNCO source). Otherwise, the jitter occurs on every PWM cycle with the synchronization pulse.
When TBCTL[SYNCOSEL] = 0 (EPWMxSYNCI is EPWMxSYNCO source), a software synchronization pulse can be issued only once during high-resolution period initialization. If a software sync pulse is applied while the PWM is running, the jitter appears on the PWM output at the time of the sync pulse.