LPC1768 Novice Learning GPIO and External Interrupts

The P0 and P2 ports of LPC1768 can be used for input and output, and can also be configured as interrupt sources.

Now P2.10 is used as a button and is configured as follows:

void BUTTON_init(void)

{

 LPC_GPIO2->FIODIR      &=~(1 << 10);    /* PORT2.10 definedas input       */

 LPC_GPIOINT->IO2IntEnF |=  (1<< 10);    /* enable falling edgeirq         */

 NVIC_EnableIRQ(EINT3_IRQn);             /* enable irq in nvic             */

}

void EINT3_IRQHandler()

{

 LPC_GPIOINT->IO2IntClr |= (1 << 10);     /* clear pending interrupt         */

    LED_ON;

Dealy(1000);

 LED_OFF;

}

EINT3 and GPIO interrupts are shared, so pressing a button directly enters the EINT3 interrupt service routine.

The lpc1768 has 4 external interrupt inputs, P2.10~P2.13, and P2.10 is also used as the button

void EINTInit( void )

{

 LPC_PINCON->PINSEL4 = 0x00100000;      /*set P2.10 as EINT0 and

                                                               P2.0~7GPIO output */

 LPC_GPIO2->FIODIR = 0x000000FF;    /*port 2, bit 0~7 only */

 LPC_GPIO2->FIOCLR = 0x000000FF;   /*turn off LEDs */

  LPC_SC->EXTMODE = EINT0_EDGE;             /* INT0 edge trigger */

 LPC_SC->EXTPOLAR = 0;                          /* INT0 is falling edge by default */

 NVIC_EnableIRQ(EINT0_IRQn);

 return( TRUE );

}

void EINT0_IRQHandler (void)

{

 LPC_SC->EXTINT = EINT0;          /* clear interrupt */   //EINT0==0x10

              LED_ON;

Dealy(1000);

 LED_OFF;

}