#INCLUDE <16C505.h>
#FUSES INTRC, RB4, NOWDT, NOPROTECT, NOMCLR
#USE DELAY (CLOCK=4000000)

#define AD_CS pin_C0
#define AD_CK pin_C1
#define AD_DO pin_C2

int adVal;	//This variable holds result from A/D conversion.

/* This function initiates a conversion from the ADC0831 A/D convertor, 
   then reads the value from the A/D convertor and puts the result into 
   the variable adVal.
*/
void AD_Read() {
	int i;
	output_low(AD_CS); 	//Select chip (initiate conversion.

	for (i=0; i<2; i++) {
		output_high(AD_CK);   //cycle clock twice (while converstion starts.
		delay_us(10);
		output_low(AD_CK);
		delay_us(10);
	}
	for (i=0;i<8;i++) {	//Read in value from A/D convertor
		output_high(AD_CK);
		delay_us(10);
		shift_left(&adVal, 1, input(AD_DO));
		output_low(AD_CK);
		delay_us(10);
	}

	output_high(AD_CK); //cycle clock once.
	delay_us(10);
	output_low(AD_CK);
	delay_us(10);

	output_high(AD_CS); //Deselect chip.
}



/* Main routine - Read A/D convertor 10 times per second

void main() {
	output_low(AD_CK); 	//Initialize A/D
	output_high(AD_CS);
	setup_counters(RTCC_INTERNAL,RTCC_DIV_256);

	while(1) {
		output_low(pin_b0);	//Turn off all LEDS
		output_low(pin_b1);
		output_low(pin_b2);
		output_low(pin_b4);

		AD_Read();			//Read A/D convertor
		if (adVal>51) output_high(pin_b0);	//LED1 for Vin>1 volt
		if (adVal>102) output_high(pin_b1);	//LED2 for Vin>2 volt
		if (adVal>153) output_high(pin_b2);	//LED3 for Vin>3 volt
		if (adVal>204) output_high(pin_b4);	//LED4 for Vin>4 volt

		delay_ms(100);			//Wait 0.1 seconds.
	}
}