CCS/TMS320F28379D: HRPWM Question

Hi Anton,

I am looking into this issue. Just a quick check, which all pwm instances you are using in your example as HRPWM is available only for pwm1-pwm8 for this device?

Thanks
Vasudha

Hi Vasudha,

Microcontroller has 8 PWM-Channels and I want to use all of them as HRPWM.
So in code:
volatile struct EPWM_REGS *ePWM[] = { &EPwm1Regs, &EPwm2Regs, &EPwm3Regs, &EPwm4Regs, &EPwm5Regs, &EPwm6Regs, &EPwm7Regs, &EPwm8Regs};

Thanks!

UPDATE
I have written a small program for debugging
-----------------------------------------------------------------------
//
// Included Files
//
#include "F28x_Project.h"
#include "SFO_V8.h"
#include "math.h"

//
// Defines
//
#define PWM_CH 9 // # of PWM channels for SFO()
#define MODMAX 8 // # of PWM channels for Program
//
// Globals
//
float D=0.417, temp, CMPAref, CMPAHRref, ttemp, PHS, PHSHR;

int Module = 3;
float t=0, k=0;

int MEP_ScaleFactor; // Global variable used by the SFO library

volatile struct EPWM_REGS *ePWM[MODMAX] =
{ &EPwm1Regs, &EPwm2Regs, &EPwm3Regs, &EPwm4Regs, &EPwm5Regs,
&EPwm6Regs, &EPwm7Regs, &EPwm8Regs};


void HRPWM_Config(int);

void main(void)
{
int i, j;

EALLOW; // This is needed to write to EALLOW protected registers

InitSysCtrl();

EDIS;

InitEPwmGpio();

DINT; // Disable CPU interrupts

InitPieCtrl();


EALLOW;
IER = 0x0000;
IFR = 0x0000;

InitPieVectTable();

EINT; // Enable Global interrupt INTM
ERTM; // Enable Global realtime interrupt DBGM

while (SFO() == 0) {} // MEP_ScaleFactor calculated by MEP Cal Module

HRPWM_Config(2500); // ePWMx target
while(1)
{

for(i=0;i<Module;i++)
{
(*ePWM[i]).AQCSFRC.bit.CSFA = 0; // A not trigger
(*ePWM[i]).AQCSFRC.bit.CSFB = 0; // B not trigger

if(i<=(Module)/2)
{
k = (*ePWM[i]).TBPRD*2/(float)(Module)*i;
PHSHR = modff(k, &PHS);
(*ePWM[i]).TBPHS.all = ((long)PHS)<<16 | (long)PHSHR<<8;
(*ePWM[i]).TBCTL.bit.PHSDIR = TB_DOWN;
}
else
{
t = (*ePWM[i]).TBPRD*2/(float)Module*i;
ttemp = (float)((*ePWM[i]).TBPRD*2 - t);
PHSHR = modff(ttemp, &PHS);
(*ePWM[i]).TBPHS.all = ((long)PHS)<<16 | (long)PHSHR<<8;
(*ePWM[i]).TBCTL.bit.PHSDIR = TB_UP;
}

temp = (D*(*ePWM[i]).TBPRD);
CMPAHRref = modff(temp, &CMPAref);
(*ePWM[i]).CMPA.all = ((long)CMPAref)<<16 | (long)CMPAHRref<<8;
}

for(j=Module;j<8;j++)
{
(*ePWM[j]).AQCSFRC.bit.CSFA = 2; // A HIGH
(*ePWM[j]).AQCSFRC.bit.CSFB = 2; // B HIGH
}

while (SFO() == 0) {} // MEP_ScaleFactor calculated by MEP Cal Module

} //while
} //main

void HRPWM_Config(period)
{
Uint16 j;

EALLOW;
CpuSysRegs.PCLKCR0.bit.TBCLKSYNC = 0; // Disable TBCLK within the EPWM
EDIS;

for(j=0; j<MODMAX; j++)
{
(*ePWM[j]).TBCTL.bit.PRDLD = TB_SHADOW; // set Shadow load
(*ePWM[j]).TBPRD = period; // PWM frequency = 1/(2*TBPRD)
(*ePWM[j]).CMPA.bit.CMPA = period / 2; // set duty 50% initially
(*ePWM[j]).CMPA.bit.CMPAHR = (1 << 8); // initialize HRPWM extension

(*ePWM[j]).TBCTR = 0;

(*ePWM[j]).TBCTL.bit.CTRMODE = TB_COUNT_UPDOWN; // Select up-down count mode

(*ePWM[j]).TBCTL.bit.HSPCLKDIV = TB_DIV1;
(*ePWM[j]).TBCTL.bit.CLKDIV = TB_DIV1; // TBCLK = SYSCLKOUT
(*ePWM[j]).TBCTL.bit.FREE_SOFT = 11;

(*ePWM[j]).CMPCTL.bit.LOADAMODE = 2; // load on CTR=0 or CTR=PRD
(*ePWM[j]).CMPCTL.bit.LOADBMODE = 2;
(*ePWM[j]).CMPCTL.bit.SHDWAMODE = CC_SHADOW;
(*ePWM[j]).CMPCTL.bit.SHDWBMODE = CC_SHADOW;

(*ePWM[j]).AQCTLA.bit.CAU = AQ_SET; // PWM toggle high/low
(*ePWM[j]).AQCTLA.bit.CAD = AQ_CLEAR;
(*ePWM[j]).AQCTLB.bit.CAD = AQ_SET; // PWM toggle high/low
(*ePWM[j]).AQCTLB.bit.CAU = AQ_CLEAR;

EALLOW;
(*ePWM[j]).HRCNFG.all = 0x0;
(*ePWM[j]).HRCNFG.bit.EDGMODE = HR_BEP; // MEP control on both edges.
(*ePWM[j]).HRCNFG.bit.CTLMODE = HR_PHS; // CMPAHR and TBPRDHR HR control.
(*ePWM[j]).HRCNFG.bit.HRLOAD = HR_CTR_ZERO_PRD; // load on CTR = 0 and CTR = TBPRD
(*ePWM[j]).HRCNFG.bit.EDGMODEB = HR_BEP; // MEP control on both edges
(*ePWM[j]).HRCNFG.bit.CTLMODEB = HR_PHS; // CMPBHR and TBPRDHR HR control
(*ePWM[j]).HRCNFG.bit.HRLOADB = HR_CTR_ZERO_PRD; // load on CTR = 0 and CTR = TBPRD
(*ePWM[j]).HRCNFG.bit.AUTOCONV = 1; // Enable autoconversion for HR period

(*ePWM[j]).HRPCTL.bit.TBPHSHRLOADE = 1; // Enable TBPHSHR sync (required for updwn count HR control)
(*ePWM[j]).HRPCTL.bit.HRPE = 1; // Turn on high-resolution period control.
//################
(*ePWM[j]).TBPHS.all = 0;
(*ePWM[j]).TBCTL.bit.SYNCOSEL = TB_SYNC_IN;
(*ePWM[j]).TBCTL.bit.PHSEN = TB_ENABLE;
(*ePWM[0]).TBCTL.bit.PHSEN = TB_DISABLE;
//################
CpuSysRegs.PCLKCR0.bit.TBCLKSYNC = 1;
(*ePWM[j]).TBCTL.bit.SWFSYNC = 1;
EDIS;
}
}
---------------------------------------------------------------------------------------------------------------------------------------------------
With it's help I've discovered, that the problem with HRPWM occur, when I'm enabling a phase shifting.
Without a part of code in //### signs, all PWM modules works in HR mod but without phase shifting (of course). When I am enabling phase shifting, HR Mod works only for first PWM modul.
For D=0.417 Duty Cycle on oscillograph must be 58.3%. I've become 58.301% for first channel and 58.321% for all others (With Phase shifting). I've become DC=58.301% for all channels (Without PHS). With normal ePWM, I've become DC=58.321% for all PWM-channels.

The big problem is also that TI give no example code for use of TBPHSHR.......
Thank you, I hope this info will help you to help me))

Hello Anton,

First of all, I see an issue with the HRCNFG[CTLMODE] configuration in your code. This bit should be set to 0, to allow hi-res duty control with hi-res phase shift control. This should fix a lot, if not all, of the issues you are seeing with duty cycle mismatches.

Second, is the PWM output frequency fixed or variable? If it is variable, please refer to the example in C2000Ware located at <path_to_C2000Ware>\device_support\f2837xd\examples\cpu1\hrpwm_deadband_sfo_v8.

This example implements HRPRD (hi-res period), HRDUTY (hi-res duty), HRPHS (hi-res phase shift) and HRDB (hi-res dead-band) simultaneously without any of the TBPHSHR issues you are seeing.

I hope this helps.

Hrishi

Hello Hrishi, thank you for your advice!

Unfortunately in my case HRCNFG[CTLMODE] makes no effect on PWM... Setting HRCNFG[CTLMODE] to 0x1 was a desperate attempt to change something...
However I will take in account your advice =)

Сoncerning second point - no, I use constant frequensy but different duty cycles and phase shifting values.

Have you some ideas else?)

I suporse problems with synchronisation.
I have programmed regs TBCTL.bit.SWFSYNC and TBCTL.bit.SYNCOSEL as it recommended in datasheet, but for example register EPwmxRegs.EPWMxSYNCOUT.SWEN is absent.... But in datasheet for SWEN is written:

"This bit enables the TBCTL.SWFSYNC bit to set the
EPWMxSYNCO signal.
0 Disabled
1 The EPWMxSYNCO signal is pulsed for one PWM clock period
when the TBCTL.SWFSYNC bit is set"

Hi Anton,

I am sorry I missed your main question in the first post (i.e. "how could I calculate MEP_ScaleFaktor for other channels?") and instead focused on the code itself.

The MEP scale factor is the same for all PWMs on the device. Please enable AUTOCONV for all PWMs and this will be taken care of by the PWM logic on the device. When AUTOCONV is enabled, the fractional HR value should be written to the CMPAHR register as follows. (remember only most significant 8-bits of CMPAHR are used for this):

To write a fractional value of 0.2 calculate 0.2*(0xFF00) = 0x3300. This value should then be written to CMPAHR.

Also, if you are not using high resolution frequency control, please disable HRPE.

I hope this helps.

Hrishi

Hello Hrishi, thank you for the answer! =)

As you can see in the last code example from me, I use HR registers, as you say.
Probem is now with TBPHS and namely with syncronisation. You can reed my post up)

Best regards,
Anton

Hi Anton,

Apologies for your follow-up reply being dropped. Are you still working through PWM synchronization and still have any related questions?

If you don't have any more questions, you can press the "This resolved my issue" button on the relevant replies. If you do, please let us know by responding with the details.

Regards,
Elizabeth

Hallo Elizabeth,

yes, I still have this problem... T_T
When I'm working with 8 PWMs and (*ePWM[j]).TBCTL.bit.PHSEN = TB_DISABLE; I've become HRPWM on all 8 channels.[j=0..7]
But when I turning (*ePWM[j]).TBCTL.bit.PHSEN = TB_ENABLE; [j=1..7] (Disabled for first channel), I've become HRPWM only on first channel and on rest 7 - normaly ePWM...

Best regards,
Anton

Hi Anton,

I haven't heard from you in more than 2 weeks, so I'm checking in if you were able to resolve this. If not, please reject this resolution and reply to this thread.

This thread will lock after 60 days of inactivity. If this thread locks and you have remaining questions, please feel free to make a new thread describing the current status of your issue. Thank you for using the TI C2000 E2E forum.

Regards,
Elizabeth