adc.c

#include"adc.h"
#include"delay.h"





/***************************************************************************************************
                         void ADC_Init()
****************************************************************************************************
 * I/P Arguments: none.
 * Return value	: none

 * description :This function initializes the ADC module.
***************************************************************************************************/
void ADC_Init()
{

	     adc_Start=0;                //Initialize all the control lines to zero.
		 adc_ALE=0;
		 adc_OE=0;
		 adc_EOC=1;                  //Configure the EOC pin as I/P
	   adc_databus=0xff;             //configure adc_databus as input
}




***************************************************************************************************/
uint16_t ADC_GetAdcValue(uint8_t var_adcChannel_u8)
{
   	 uint16_t adc_result;

   	   adc_A=((var_adcChannel_u8>>0) & 0x01);   //Selectthe channel
   	   adc_B=((var_adcChannel_u8>>1) & 0x01);   //for which the conversion needs to be done
   	   adc_C=((var_adcChannel_u8>>2) & 0x01);

		adc_ALE=1;         // Latch the address by making the ALE high.
		DELAY_us(50);
		adc_Start=1;       //Start the conversion after latching the channel address
		DELAY_us(25);

		adc_ALE=0;         //Pull ALE line to zero after starting the conversion.
		DELAY_us(50);
		adc_Start=0;       //Pull Start line to zero after starting the conversion.

     while(adc_EOC==0);    // Wait till the ADC conversion is completed,
                           // EOC will be pulled to HIGH by the hardware(ADC0809)
                           // once conversion is completed.

		 adc_OE=1;         //Make the Output Enable high
		                   //to bring the ADC data to port pins
		 DELAY_us(25);
     adc_result=adc_databus;  //Read the ADC data from ADC bus
		  adc_OE=0;			  //After reading the data, disable th ADC output line.

	  return(adc_result) ;

  }