sevenSegmentCode.c

#include <lpc214x.h>

unsigned char getAlphaCode(unsigned char alphachar)
{
	switch (alphachar)
	{
		// dp g f e d c b a - common anode: 0 segment on, 1 segment off
		case '0': return 0xc0;
		case '1': return 0xf9;
		case '2': return 0xa4;
		case '3': return 0xb0;
		case '4': return 0x99;
		case '5': return 0x92;
		case '6': return 0x82;
		case '7': return 0xf8;
		case '8': return 0x80;
		case '9': return 0x98;
		//simmilarly add for other digit/characters
		default : break;
	}
	return 0xff;
}

void alphadisp7SEG(char *buf)
{
	unsigned char i,j;
	unsigned char seg7_data,temp=0;
	for(i=0;i<5;i++) // because only 5 seven segment digits are present
	{
		seg7_data = getAlphaCode(*(buf+i));
		// instead of this look up table can be used
		// to shift the segment data(8bits)to the hardware (shift registers) using Data,Clock,Strobe

		for (j=0 ; j<8; j++)
		{
			//get one bit of data for serial sending
			temp = seg7_data & 0x80; // shift data from Most significan bit (D7)
			if(temp == 0x80)
			IOSET0 |= 1 << 19; //IOSET0 | 0x00080000;
			else
			IOCLR0 |= 1 << 19; //IOCLR0 | 0x00080000;
			//send one clock pulse
			IOSET0 |= 1 << 20; //IOSET0 | 0x00100000;
			delay_ms(1);
			IOCLR0 |= 1 << 20; //IOCLR0 | 0x00100000;

			seg7_data = seg7_data << 1; // get next bit into D7 position

		}
	}
	IOSET0 |= 1 << 30; //IOSET0 | 0x40000000;
	delay_ms(1); //nop();
	IOCLR0 |= 1 << 30; //IOCLR0 | 0x40000000;
	return;
}