TMS320F28377D: HRPWM Output A and B are Complementary with Deadband

Hi Olga,

I believe this is possible per:
e2e.ti.com/.../654568

Devin,

Thank you for the quick reply! The answer in the thread that you referenced confused me and didn't make it clear whether output B can be both dependent on A and in high resolution. I understood that HR is applied after the deadband module so output B can only be in high resolution only if it is independent of A?

What I have observed with my set up is that output A is operating in high resolution as intended. Output B is set as active high complementary of output A with 10ns deadband and it doesn't move with high precision as output A does, i.e. changing the duty cycle a little bit moves the falling edge of A but doesn't change B at all. I was wondering if I am just missing something in my settings or if output B is not meant to be in high resolution when being dependent on A with deadband.

Here are my PWM settings:

EPwm2Regs.TBCTL.bit.PRDLD = TB_IMMEDIATE;
EPwm2Regs.TBCTL.bit.CTRMODE = 0; // Up
EPwm2Regs.TBCTL.bit.HSPCLKDIV = TB_DIV1;
EPwm2Regs.TBCTL.bit.CLKDIV = TB_DIV1;

EPwm2Regs.TBPRD = 39;
EPwm2Regs.AQCTLA.bit.ZRO = AQ_SET;
EPwm2Regs.AQCTLA.bit.CAU = AQ_CLEAR;
EPwm2Regs.CMPA.bit.CMPA = 0;

EPwm2Regs.DBCTL.bit.HALFCYCLE = 1;
EPwm2Regs.DBCTL.bit.OUT_MODE = DB_FULL_ENABLE;
EPwm2Regs.DBCTL.bit.POLSEL = DB_ACTV_HIC;
EPwm2Regs.DBFED.bit.DBFED = 2;
EPwm2Regs.DBRED.bit.DBRED = 2;

EPwm2Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO;
EPwm2Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW;
EPwm2Regs.HRCNFG.all = 0x0;
EPwm2Regs.HRCNFG.bit.CTLMODE = HR_CMP;
EPwm2Regs.HRCNFG.bit.EDGMODE = HR_FEP;
EPwm2Regs.HRCNFG.bit.HRLOAD = HR_CTR_ZERO;
EPwm2Regs.HRCNFG.bit.SELOUTB = HR_NORM_B;
EPwm2Regs.HRCNFG.bit.AUTOCONV = 1;

Hi Olga,

Bear with me as the main HRPWM owner is out-of-office.

Per section "15.2.5 Deadband High Resolution Operation" in the TRM there is a note:

"Just like the duty cycle restrictions when using HRPWM, the DBRED and DBFED values
must be greater than 3 to use hi-res deadband."

I read this as the the deadband values will need to be at least 3 (half-cycles?) for HR deadband to operate, so you may want to try increasing DBFED and DBRED to at least 3.

I think you also need to enable HR Deadband in
HRCNFG2.bit.EDGMODEDB = 2; //10: MEP control of falling edge (CMPAHR)