How to use external pin interrupts

[lpcware]

Content originally posted in LPCWare by emielzij on Sun Jan 25 11:57:45 MST 2015
I want to trigger an ISR if an external pin changes state.

This is my code at the moment:

#include "lpc11xx.h"

int main(void)
{
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 16);//Enable iocon clock

LPC_IOCON->PIO0_1&= 0xFFFFFFF8;//PIO0_1 as standard GPIO

LPC_GPIO0->DIR &= ~(1 << 1);//PIO0_1 as input

LPC_GPIO0->IS &= ~(1 << 1);//PIO0_1 as edge sensitive

LPC_GPIO0->IBE |= (1 << 1);//Both edges trigger an interrupt

LPC_GPIO0->IE|= (1 << 1);//Not mask the interrupt of this pin anymore


NVIC_EnableIRQ(EINT0_IRQn);

    while(1)
    {

    }
    return 0 ;
}


void EINT0_IRQHandler(void)
{
//Check which pin triggered an interrupt
        //Some code
        //Clear interrupt flag
}

I know that some statements are redundant.

How can I check which pin is interrupted in the isr, is this the GPIOnRIS register?
And in which register do I need to clear the interrupt at the end of my ISR?

Regards

[lpcware]

Content originally posted in LPCWare by R2D2 on Mon Jan 26 04:45:28 MST 2015

---

Quote: emielzij
edit: I think that the GPIOnMIS register should be checked to figure out which pin caused the interrupt. Would be nice if someone could confirm this.

---

So you are using masked interrupts? Otherwise I would recommend to read RAW interrupt status register 

CMSISv2p00 Sample:

#include "LPC11xx.h"

volatile uint32_t counter=0;

#define INT_PIN(1<<0)//select pin of GPIO1

void PIN_init(void)
{
//Set ext interrupt
 LPC_IOCON->R_PIO1_0 |= 0x01;   //select GPIO
 LPC_GPIO1->DIR &=~INT_PIN;//input
 LPC_GPIO1->IS  &=~INT_PIN;//0: edge sensitive
 LPC_GPIO1->IBE &=~INT_PIN;//0: trigger on IEV
 LPC_GPIO1->IEV &=~INT_PIN;//0: trigger low interrupt
 LPC_GPIO1->IE  |= INT_PIN;//1: enable interrupt
 NVIC_EnableIRQ(EINT1_IRQn);
}

//PIO1 interrupt handler
void PIOINT1_IRQHandler(void)      // PIOINT1
{
 if(LPC_GPIO1->RIS & INT_PIN)//read raw interrupt status
 {
  counter ++;
  LPC_GPIO1->IC |= INT_PIN;__NOP();__NOP();//clear edge detection
 }
}

int main(void)
{
 volatile static int i = 0;
 PIN_init();
 while(1)
 {
  i++ ;
 }
 return 0 ;
}

[lpcware]

Content originally posted in LPCWare by emielzij on Mon Jan 26 04:18:16 MST 2015
I took a look at the example. But I don't understand what is going on. I really prefer programing the registers directly. But I can't figure out which register I should use to check which pin caused an interrupt and how to clear the interrupt at the end of the ISR. Hope someone can help me with this problem.

I am using the LPC11C24

edit: I think that the GPIOnMIS register should be checked to figure out which pin caused the interrupt. Would be nice if someone could confirm this.

[lpcware]

Content originally posted in LPCWare by R2D2 on Sun Jan 25 22:36:14 MST 2015
What about LPCOpen sample  :quest:

Something like: nxp_lpcxpresso_11c24_periph_pinint