LPC43xx Timer Interrupt Issue

samkaos · ‎06-13-2018

I have written some pulse control software for LPC4337 @ 200MHz. Some code is in M0 but of no consequence. Most of the code is in M4.

M4:-

It uses 4 timers (0-3), and 4 Match compares per timer. 1us timer clock

The Matches generate interrupts, and those interrupts check the IR[] to find the source, clear that bit, and manually control an individual GPIO output.

Something strange is happening. At random intervals (anywhere from 18 seconds to 20 mins), Timer 2 Match 3 INT gets missed! ALL OTHER TIMER INTS ARE OK. It will miss a single INT, then next time the compare register is set the INT works fine.

I cannot explain it, all INTs use similar code, and the code that sets the compare registers is similar.

So, Timer 0 Match 0-3 OK

Timer 1 Match 0-3 OK

Timer 2 Match 0 OK, 1 OK, 2 OK, 3 Glitches (IR[2] & 0x08)

Timer 3 Match 0-3 OK

SCT is unused

-Sam

Hui_Ma · ‎06-24-2018

Hi,

I do a quick test with LPCXpresso4337 board Timer2 match 3 at [timers] of [lpcopen_3_02_keil_iar_xpresso4337] software package.

I don't find you mentioned issue.

Could you only do the test with Timer2 Match3, if there still with the same issue?

I attached my test code for your reference.

best regards,

Mike

samkaos · ‎06-21-2018

Trigger software (activated by an external trigger)

if (Number == 0 && PipNum == 1)

{

LPC_GPIO_PORT->SET[3] |= 0x00000020; LPC_TIMER2->MR[0] = LPC_TIMER2->TC + Want;

LPC_TIMER2->IR |= 1; // Clear Flag

Number ++;

if (Number >= 6)

Number = 0;

}

else if (Number == 1 && PipNum == 2)

{

LPC_GPIO_PORT->SET[3] |= 0x00000010; LPC_TIMER2->MR[1] = LPC_TIMER2->TC + Want;

LPC_TIMER2->IR |= 2; // Clear Flag

Number ++;

if (Number >= 6)

Number = 0;

}

else if (Number == 2 && PipNum == 3)

{

LPC_GPIO_PORT->SET[2] |= 0x00000010; LPC_TIMER2->MR[2] = LPC_TIMER2->TC + Want;

LPC_TIMER2->IR |= 4; // Clear Flag

Number ++;

if (Number >= 6)

Number = 0;

}

else if (Number == 3 && PipNum == 4)

{

LPC_GPIO_PORT->SET[5] |= 0x00010000; LPC_TIMER2->MR[3] = LPC_TIMER2->TC + Want;

LPC_TIMER2->IR |= 8; // Clear Flag

Number ++;

if (Number >= 6)

Number = 0;

}

else if (Number == 4 && PipNum == 5)

{

LPC_GPIO_PORT->SET[2] |= 0x00004000; LPC_TIMER3->MR[0] = LPC_TIMER3->TC + Want;

LPC_TIMER3->IR |= 1; // Clear Flag

Number ++;

if (Number >= 6)

Number = 0;

}

else if (Number == 5 && PipNum == 6)

{

LPC_GPIO_PORT->SET[2] |= 0x00000004; LPC_TIMER3->MR[1] = LPC_TIMER3->TC + Want;

LPC_TIMER3->IR |= 2; // Clear Flag

Number ++;

if (Number >= 6)

Number = 0;

}

samkaos · ‎06-21-2018

Timer INT routines:-

void TIMER2_IRQHandler(void) // Switch off solenoids 1-4

{

asm("CPSID i"); // Disable all interrupts

if ((LPC_TIMER2->IR & 0x01) != 0)

{

LPC_TIMER2->IR |= 1; // Clear Flag

if (oneshot == 1)

{

oneshot = 2;

LPC_GPIO_PORT->CLR[3] |= 0x00000010;

LPC_GPIO_PORT->CLR[2] |= 0x00000010;

LPC_GPIO_PORT->CLR[5] |= 0x00010000;

LPC_GPIO_PORT->CLR[2] |= 0x00004000;

LPC_GPIO_PORT->CLR[2] |= 0x00000004;

LPC_GPIO_PORT->CLR[2] |= 0x00000002;

LPC_GPIO_PORT->CLR[2] |= 0x00000001;

}

LPC_GPIO_PORT->CLR[3] |= 0x00000020;

}

if ((LPC_TIMER2->IR & 0x02) != 0)

{

LPC_TIMER2->IR |= 2; // Clear Flag

LPC_GPIO_PORT->CLR[3] |= 0x00000010;

}

if ((LPC_TIMER2->IR & 0x04) != 0)

{

LPC_TIMER2->IR |= 4; // Clear Flag

LPC_GPIO_PORT->CLR[2] |= 0x00000010;

}

if ((LPC_TIMER2->IR & 0x08) != 0)

{

LPC_TIMER2->IR |= 8; // Clear Flag

LPC_GPIO_PORT->CLR[5] |= 0x00010000;

}

LPC_TIMER2->IR |= 0xF0;

asm("CPSIE i"); // Enable all interrupts

}

//

void TIMER3_IRQHandler(void)

{

asm("CPSID i"); // Disable all interrupts

if ((LPC_TIMER3->IR & 0x01) != 0)

{

LPC_TIMER3->IR = 1; // Clear Flag

LPC_GPIO_PORT->CLR[2] |= 0x00004000;

}

if ((LPC_TIMER3->IR & 0x02) != 0)

{

LPC_TIMER3->IR = 2; // Clear Flag

LPC_GPIO_PORT->CLR[2] |= 0x00000004;

}

if ((LPC_TIMER3->IR & 0x04) != 0)

{

LPC_TIMER3->IR = 4; // Clear Flag

LPC_GPIO_PORT->CLR[2] |= 0x00000002;

}

if ((LPC_TIMER3->IR & 0x08) != 0)

{

LPC_TIMER3->IR = 8; // Clear Flag

LPC_GPIO_PORT->CLR[2] |= 0x00000001;

}

// LPC_TIMER3->IR |= 0xF0;

asm("CPSIE i"); // Enable all interrupts

}

Hui_Ma · ‎06-18-2018

Hi Sam,

From the description, you are using Timer module for match compares, not State Configurable Timer (SCT).

Could you provide the test code for Timer 2? I could do a onsite test.

Have a great day,
Mike

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