SPRUHM9H October 2014 – May 2024 TMS320F28075 , TMS320F28075-Q1 , TMS320F28076
The ramp generator makes state changes on every rising edge of DACSOURCE, EPWMSYNCPER, and COMPHSTS.
On the rising edge of DACSOURCE: RAMPMAXREFA, RAMPDECVALA, and RAMPDLYA are loaded with the shadow registers. RAMPSTS is loaded with RAMPMAXREFS.
On the rising edge of the selected EPWMSYNCPER: RAMPMAXREFA, RAMPDECVALA, and RAMPDLYA are loaded with the shadow registers. RAMPSTS is loaded with RAMPMAXREFS and starts decrementing when RAMPDLYA counter reaches zero.
On the rising edge of COMPHSTS with RAMPLOADSEL = 1: RAMPMAXREFA, RAMPDECVALA, and RAMPDLYA are loaded with the shadow registers. RAMPSTS is loaded with RAMPMAXREFS and stops decrementing.
On the rising edge of COMPHSTS with RAMPLOADSEL = 0: RAMPSTS is loaded with RAMPMAXREFA and stops decrementing.
Additionally, if the value of RAMPSTS reaches zero, the RAMPSTS register remains static at zero until the next EPWMSYNCPER is received. These state changes are illustrated in the ramp generator block diagram in Figure 12-4.