SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
In high resolution mode, the MEP is not active for 100% of the PWM period. It becomes operational 3 FICLK cycles after the period starts.
Duty cycle range limitations are illustrated in Figure 12-2653. This limitation imposes a lower duty cycle limit on the MEP. For example, precision edge control is not available all the way down to 0% duty cycle. Although for the first 3 or 6 cycles, the HRPWM capabilities are not available, regular PWM duty control is still fully operational down to 0% duty. In most applications this should not be an issue as the controller regulation point is usually not designed to be close to 0% duty cycle.
If the application demands HRPWM operation in the low percent duty cycle region, then the HRPWM can be configured to operate in count-down mode with the rising edge position (REP) controlled by the MEP. This is illustrated in Figure 12-2654. In this case low percent duty limitation is no longer an issue.