ARM_CORTEX_M3_LPC1768_LED_BLINK.c

#define PINSEL4 0x4002C010
#define PINMODE4 0x4002C050
#define PCONP 0x400FC0C4
#define PINMODE_OD2 0x4002C070
#define FIO2DIR 0x2009C040
#define FIO2SET  0x2009C058
#define FIO2CLR 0x2009C05C

int delay_ms(unsigned long millisecond)
{
	unsigned long i=0,j=0;
	for(i=0;i<millisecond;i++)
	for(j=0;j<23000;j++);
	return 0;
}


int main()
{
	// want to blink the LED at PORT 2.2 only ..
	// selecting the power on function for the GPIOs.
	// PINCON register bit 15 (1)
	// The reset value is 1 so no need to configure this bit
	*((unsigned long *)PCONP) |= (1<<15);
	// configuring the PINSEL4 (add = 0x4002 C010)
	// selecting the function0 in PINSEL register ..
	*((unsigned long *)PINSEL4) &= ~(unsigned long)((1<<5)|(1<<4));
	// now configuring the PINMODE register to enable the internal pull up register ..
	//selecting the 00 in PINMODE4 bit 5,4
	*((unsigned long *)PINMODE4) &= ~(unsigned long)((1<<5)|(1<<4));
	// now configuring the open drain mode of the particular pin
	// I don't want it to be open drain so bit 2 should be 0 (reset value is 0 so no need to configure it)
	*((unsigned long *)PINMODE_OD2) &= ~((unsigned long)(1<<2));


	// now configuring the GPIOs
	// FIODIR FIO2DIR - 0x2009 C040
	// setting the bit as output ..
	*((unsigned long *)FIO2DIR) |=(unsigned long)(1<<2);

	while(1)
	{
		// now setting the register ..
		*((unsigned long *)FIO2SET) |= (unsigned long)(1<<2);
		delay_ms(1000);
		*((unsigned long *)FIO2CLR) |= (unsigned long)(1<<2);
		delay_ms(1000);
	}

	return 0;
}