TMS320F28377D: not getting calculated EPWM interrupt

nileshkumar koladiya

Part Number: TMS320F28377D
Other Parts Discussed in Thread: TMS320F28379D,

Hi,

I have developed my Fimware for TMS320F28379D using launchpad kit with ysstem clock of 200Mhz, configured PWM12 in up-down mode, TBPRD is 27777.

void InitPwm12(void)
{
EALLOW;
EPwm12Regs.TBPRD = 27777; //
EPwm12Regs.TBPHS.bit.TBPHS = 0x0000; // Phase is 0
EPwm12Regs.TBCTR = 0x0000; // Clear counter

EPwm12Regs.TBCTL.bit.CTRMODE = TB_COUNT_UPDOWN; // Count up and down
EPwm12Regs.TBCTL.bit.PHSEN = TB_ENABLE; // Disable phase loading
EPwm12Regs.TBCTL.bit.HSPCLKDIV = TB_DIV1; // Clock ratio to SYSCLKOUT
EPwm12Regs.TBCTL.bit.CLKDIV = TB_DIV1;

EPwm12Regs.TBCTL.bit.SYNCOSEL = TB_SYNC_IN;

EPwm12Regs.DBCTL.bit.IN_MODE = DBA_ALL;
EPwm12Regs.DBCTL.bit.POLSEL = DB_ACTV_HIC;
EPwm12Regs.DBCTL.bit.OUT_MODE = DB_FULL_ENABLE;

EPwm12Regs.DBFED.bit.DBFED= FED_TIME*SYSTEM_CLOCKOUT;
EPwm12Regs.DBRED.bit.DBRED= FED_TIME*SYSTEM_CLOCKOUT;

EPwm12Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW;
EPwm12Regs.CMPCTL.bit.SHDWBMODE = CC_SHADOW;
EPwm12Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO_PRD; // Load on Zero
EPwm12Regs.CMPCTL.bit.LOADBMODE = CC_CTR_ZERO_PRD;

#ifdef EPWM12_INT_ENABLE
EPwm12Regs.ETSEL.bit.INTSEL = ET_CTR_PRDZERO; // Select INT on Zero event
EPwm12Regs.ETSEL.bit.INTEN = 1; // Enable INT
EPwm12Regs.ETPS.bit.INTPRD = ET_1ST; // Generate INT on 3rd event*/
#endif
EDIS;
}

according to above setting interrupt should come on each zero and prd event, i.e.138.885usec which is i am getting on development kit.

we have designed our DSP board with TMS320F28377D. I loaded same firmware to this board and checked interrupt time it is 160uSec.

i compared system clock out on both my board and launchpad, it is same 25Mhz(devided by 8 default division factor).

i also checked by changing TBPRD value to 55554 and according to that my interrupt time doubled to 320uSEc on my board and 280uSec on launchpad.

thanks in advance.

regard,

Nilesh

over 6 years ago

0 Richard Poley over 6 years ago

TI__Mastermind 27200 points

Nilesh,

A couple of things come to mind. Firstly I think you are operating the PWM out of spec. The maximum clock frequency you can apply to the PWM module is 100 MHz, not 200MHz (see table 5-12 in the datasheet). You may need to adjust the EPWMCLKDIV field in the PERCLKDIVSEL register then change your calculation of TBPRD.

Also, I noticed this line:

EPwm12Regs.TBCTL.bit.PHSEN = TB_ENABLE; // Disable phase loading

The assignment and comment don't seem to match. Is it possible PWM module 12 is being synchronized with something else?

Regards,

Richard

0 nileshkumar koladiya over 6 years ago in reply to Richard Poley

Prodigy 125 points

Dear Richard,

Thanks for giving your invaluable time on my problem.

i have set clock for pwm modules as below,

ClkCfgRegs.PERCLKDIVSEL.bit.EPWMCLKDIV = 0; //make pwm base source same as system clock

and for EPwm12Regs.TBCTL.bit.PHSEN = TB_ENABLE; // Disable phase loading, just comment is wrong. module is in sync with EPWM1.

still i will remove this sync function and will check its effect.

regard,

Nilesh koladiya

0 Richard Poley over 6 years ago in reply to nileshkumar koladiya

TI__Mastermind 27200 points

Nilesh,

Regarding...

i have set clock for pwm modules as below,

ClkCfgRegs.PERCLKDIVSEL.bit.EPWMCLKDIV = 0; //make pwm base source same as system clock

Just want to be clear; I'm saying you can't do this if you're running the device at 200 MHz. Probably you understood that, I just wanted to make sure. Thanks.

Regards,

Richard

0 nileshkumar koladiya over 6 years ago in reply to Richard Poley

Prodigy 125 points

Dear Richard,

is there any reason i can't run pwm at 200Mhz ?

is there any reference for that in datasheet or user manual of device ?

Regard,

Nilesh

0 Richard Poley over 6 years ago in reply to nileshkumar koladiya

TI__Mastermind 27200 points

Nilesh,

100 MHz is the maximum PWM clock frequency specified for this device. The datasheet reference was in my first reply.

We don't test or guarantee anything out of spec.

Regards,

Richard

0 nileshkumar koladiya over 6 years ago

Prodigy 125 points

Dear Richard,

I will change it in my coding and will check result.

Regard,

Nilesh

0 Richard Poley over 6 years ago in reply to nileshkumar koladiya

TI__Mastermind 27200 points

Thanks, Nilesh.

Sorry for the repeated replies. They are upgrading the e2e server today and it looks like something went wrong.

Regards,

Richard

0 Richard Poley over 6 years ago in reply to Richard Poley

TI__Mastermind 27200 points

Hi Nilesh,

Could you let us know if you are still in difficulty with this issue? Thanks.

Regards,

Richard

0 nileshkumar koladiya over 6 years ago in reply to Richard Poley

Prodigy 125 points

Dear Richard,

Sorry for late reply, I was little bit busy in my testing.

I changed pwm source clock to half of system clock, I.e 100Mhz and now working fine. On development kit with 200Mhz it is working ok but on my board it is not working. Right now problem is solved.

Regard,

Nilesh

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TMS320F28377D: not getting calculated EPWM interrupt