/* p6_3: Toggle blue LED by PTD4 interrupt on both edges */

/* PTD4 is configured to interrupt on both rising edge and falling edge. In the interrupt handler, the blue LED (PTD1) is toggled. */
 
#include "MKL25Z4.h"

int main(void)
{
    __disable_irq();            /* disable all IRQs */
    SIM->SCGC5 |= 0x1000;       /* enable clock to Port D */
    PORTD->PCR[1] = 0x100;      /* make PTD1 pin as GPIO */
    PTD->PDDR |= 0x02;          /* make PTD1 as output pin */
    PTD->PDOR |= 0x02;          /* turn off blue LED */

    // configure PTD4 for interrupt
    PORTD->PCR[4] |=  0x00100;  /* make it GPIO  */
    PORTD->PCR[4] |=  0x00003;  /* enable pull-up */
    PTD->PDDR &= ~0x0010;       /* make pin input */
    PORTD->PCR[4] &= ~0xF0000;  /* clear interrupt selection */
    PORTD->PCR[4] |=  0xB0000;  /* enable both edge interrupt */
    
    NVIC->ISER[0] |= 0x80000000;    /* enable INT31 (bit 31 of ISER[0]) */
    __enable_irq();             /* global enable IRQs */

    while(1)
    {
    }
}

/* A pushbutton switch is connected to PTD4 pin to trigger PORTD interrupt */
void PORTD_IRQHandler(void)
{
    if (PORTD->ISFR & 0x00000010) {
        /* toggle blue LED (PTD1) */
        PTD->PTOR |= 0x0002;   /* toggle blue LED */
        PORTD->ISFR = 0x0010;  /* clear interrupt flag */
    }
}