topic Re: MPC5744P PIT Interrupt problem in MPC5xxx

MPC5744P PIT Interrupt problem

admin — Mon, 29 Feb 2016 16:26:57 GMT

Original Content posted by David Chung.

I'm writing a simple project for Panther that uses the PIT0 ISR to to toggle a GPIO pin. I use the 160MHz PLL as the clock source, initialize PIT0, enable PIT0 interrupts in the NVIC, add the PIT0_ISR address to the interrupt table. In the ISR, I clear the interrupt flag and toggle the GPIO pin. The problem is for some reason the program only enters the ISR around 2 to 4 times before never entering again. I can see that PIT_0.TFLG0 is set so an interrupt is called by PIT0, but it's not being handled. The PIT0 init code is shown:

void PIT0_init(uint32_t LDVAL) {

volatile uint32_t dummy = 0;

PIT_0.TIMER[0].LDVAL.R = LDVAL; /* Load # PIT clocks to count */

PIT_0.TIMER[0].TCTRL.B.TIE = 1; /* Enable interrupt */

INTC_0.PSR[226].B.PRIN = 10; /* IRQ priority = 10 (31 highest) */

dummy = INTC_0.PSR[226].R;

PIT_0.TIMER[0].TCTRL.B.TEN = 1; /* enable channel */

}

The ISR is as follows:

void PIT0_isr(void) {

LED1 = ~LED1; /* Toggle LED1 port */

PIT_0.TIMER[0].TFLG.R |= 1; /* Clear interrupt flag. w1c */

}

Anyone know the cause of this issue?

Re: MPC5744P PIT Interrupt problem

martin_kovar — Mon, 29 Feb 2016 20:18:07 GMT

Hi David,

look at this example. There is shown how to set PIT.

Example MPC5744P PinToggleStationery S32DS

At the first sight, you did not correctly configure INTC_0.PSR register. You only set priority, but you did not choose the core, which will handle the interrupt.

Regards,

Martin

Re: MPC5744P PIT Interrupt problem

nathan_ — Wed, 27 Sep 2017 08:35:10 GMT

Hello,I just download the example you uploaded and tried to debug it.

I want to use the PIT module, so I made a little change in the code. My project is attached.

I met a problem when I debug it. After I press the "resume", the code will fall into a function named "dummy" and do not go on, The picture is also attached, named "dummy"

Then I set a breakpoint before the while loop, I find out the code goes well before the while loop, which means in the initiation the problem did not occur.

Could you please help me to fix the problem? I really need to work out this problem and use the PIT module.

Thank you.

Re: MPC5744P PIT Interrupt problem

martin_kovar — Wed, 27 Sep 2017 08:53:25 GMT

Hello Nathan,

you do not have installed correct interrupt service routine. Please see intc_SW_mode_isr_vectors_MPC5744P.c file in my project and add the interrupt service routine at correct address (Vector 226).

Regards,

Martin

Re: MPC5744P PIT Interrupt problem

nathan_ — Wed, 27 Sep 2017 12:41:30 GMT

The problem has been solved. Thank you so much !

Re: MPC5744P PIT Interrupt problem

nathan_ — Wed, 27 Sep 2017 13:22:36 GMT

I can not understand the set for PLL0 in the example.

According to the MPC5744P datasheet, the max of PLL0_PHI0 is 200MHz, but the example the PLL0 is set to 400MHz by the following code:

PLLDIG.PLL0DV.R = 0x58021014; // PREDIV = 1, MFD = 20, RFDPHI = 2, RFDPHI1 = 11

Is this correct?

Re: MPC5744P PIT Interrupt problem

martin_kovar — Tue, 10 Oct 2017 11:32:33 GMT

Hello,

the calculation seems to be incorrect. Correct value for 200MHz with 40MHz crystal is:

PLLDIG.PLL0DV.R = 0x3002100A // PREDIV = 1, MFD = 10, RFDPHI = 2, RFDPHI1 = 6

Regards,

Martin