topic Re: Output Compare Interrupt Not Firing in MPC5xxx

Output Compare Interrupt Not Firing

robertwynn — Fri, 17 Jan 2020 14:10:46 GMT

I am using the TRK-MPC5634M board and Codewarrior to test an output compare.

I need to know when the OC is done, so I can check some other things.

eTPU->CHAN[0].SCR.B.CIS indicates that the interrupt has fired in the ETPU.

What am I missing in order to route the interrupt back to the processor?

Thanks

partial below
void main(void)
{
init();
test();
while(1){};
}

void init(void)
{
etpuInit();
INTC_InitINTCInterrupts();
INTC_InstallINTCInterruptHandler(etpu_0_ISR, 68, 5); // interrupt for ETPU_0 (68)

fs_etpu_interrupt_enable(0);
fs_etpu_clear_chan_interrupt_flag(0);

INTC .CPR.R = 0;
asm(" wrteei 1");
}

void test(void)
{
SIU .GPDO[ETPU_A1_PIN].R ^= 1; // toggle output so I can see start

fs_etpu_oc_init_immed(0,               // channel
      FS_ETPU_PRIORITY_HIGH,             // priority
      FS_OC_MATCH_TCR1,                  // match timebase
      1000,                              // offset1
      FS_ETPU_OC_PIN_HIGH_CAPTURE_TCR1, // pin action
      10000,                             // offset2
      FS_ETPU_OC_PIN_LOW_CAPTURE_TCR1,   // pin action
      FS_ETPU_OC_INIT_PIN_NO_CHANGE);    // init pin

fs_etpu_clear_chan_interrupt_flag(0);
}

void etpu_0_ISR(void)
{
SIU .GPDO[ETPU_A1_PIN ].R ^= 1;
fs_etpu_clear_chan_interrupt_flag(0);
}

Re: Output Compare Interrupt Not Firing

davidtosenovjan — Wed, 29 Jan 2020 12:19:06 GMT

Hi, I don't see anything obvious from this code snippet. OC function works fine in other aspects? And have you tried other interrupt sources (for instance PIT) to check whether you have properly working interrupts?

Re: Output Compare Interrupt Not Firing

robertwynn — Sun, 02 Feb 2020 19:05:30 GMT

Other interrupts work fine. The OC works (i.e. the output toggles when it should). I just can't get the interrupt to fire.

Re: Output Compare Interrupt Not Firing

davidtosenovjan — Tue, 25 Feb 2020 15:37:32 GMT

I have just tried it and it works fine on my side.

I can share example code if needed

Re: Output Compare Interrupt Not Firing

robertwynn — Thu, 12 Mar 2020 20:16:10 GMT

Please share your code.

Re: Output Compare Interrupt Not Firing

davidtosenovjan — Mon, 16 Mar 2020 08:19:49 GMT

I am currently at home office without any hardware to check it but I believe I have attached the right code. Certain configuration in the main function, the rest configured with eTPU GCT, config file in the /src folder. Note that it is just raw state without any comments.

Re: Output Compare Interrupt Not Firing

robertwynn — Mon, 16 Mar 2020 14:27:52 GMT

I ran your code. The interrupt does fire, but only once. At power-up the OC and the interrupt fire, but if you reload the OC (change I made) the interrupt does not fire. I checked eTPU->CISR_A.B.CIS0 and it was still 1. I cleared it again (got 0) and the interrupt still did not fire again.

Re: Output Compare Interrupt Not Firing

davidtosenovjan — Mon, 16 Mar 2020 15:58:24 GMT

It is not supposed to.

If you need periodic pulses, use function QOM function:

https://www.nxp.com/docs/en/application-note/AN2857.pdf

Re: Output Compare Interrupt Not Firing

robertwynn — Mon, 16 Mar 2020 17:03:23 GMT

I will look at that. What I want is a way to detect when the OC is done. (without polling it), so I can load it with the next event.

I guess I don't understand the purpose/implementation of the OC interrupt.

Re: Output Compare Interrupt Not Firing

robertwynn — Thu, 16 Apr 2020 20:21:43 GMT

I finally figured out what I was missing. The default OC does not enable the interrupt.

If I add ETPU.CIER_A.B.CIE0=1 the interrupt fires at the end if the event. Just what I needed.