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Tool/software:
Hi experts,
I'm planning to use CMPSS module and ePWM module to realize one kind of current control, but I found out there's difference between waves generated by different triggering source. Here's the thing:
Constant ePWM settings:
EPwm1REGS.TBPRD = 0xFFFF;
EPwm1REGS.TBCTL.BIT.CTRMODE = TB_COUNT_DOWN;
If I configure ePWM's AQ submodule as following:
EPwm1REGS.AQCTLA.bit.CAU = AQ_CLEAR;
EPwm1REGS.AQCTLA.bit.ZRO = AQ_SET;
EPwm1REGS.CMPA.bit.CMPA = 0x7FFF;
The waveform of ePWM1A would be this:
But if I set the T1 event and T2 event as following:
EPwm1REGS.DCTRIPSEL.bit.DCAHCOMPSEL = 0x6; //CMPSS1.CTRIPH --> TRIPIN7 --> DCTRIP.A.HIGH
EPwm1REGS.DCTRIPSEL.bit.DCBHCOMPSEL = 0x7; //CMPSS1.CTRIPL --> TRIPIN8 --> DCTRIP.B.HIGH
EPwm1REGS.TZDCSEL.bit.DCAEVT1 = 0B010; //DCAH = high, DCAL = don't care
EPwm1REGS.TZDCSEL.bit.DCBEVT1 = 0B010; //DCBH = high, DCBL = don't care
EPwm1REGS.AQTSRCSEL.bit.T1SEL = 0x0; //0000: DCAEVT1
EPwm1REGS.AQTSRCSEL.bit.T2SEL = 0x2; //0010: DCBEVT1
EPwm1REGS.AQCTLA2.bit.T1D = AQ_CLEAR;
EPwm1REGS.AQCTLA2.bit.T2D = AQ_SET;
and I manually invert the CMPSS1 H&L's output in a 4khz adc_isr() by running 2 code groups in turn:
group 1:
Cmpss1Regs.COMPCTL.bit.COMPLINV = 0;
Cmpss1Regs.COMPCTL.bit.COMPHINV = 1;
group 2:
Cmpss1Regs.COMPCTL.bit.COMPLINV = 1;
Cmpss1Regs.COMPCTL.bit.COMPHINV = 0;
the waveform of ePWM1A is similar to the image above theoretically, but it's like that:
Seems it's high impedance when changing to AQ_CLEAR so I change EPwm1REGS.AQCTLA2.bit.T1D to AQ_TOGGLE, but the falling edge is still like that.
So how can I make the falling edge drop immediately (just like the former image) in this situation(the rising & falling edge must trigged by CMPSS output signals)?
