Adc.c51

#pragma cd

#include "regcc01.h"

#define uchar  unsigned char

#define uint  unsigned int

#define XTAL    20e6

#define ADC_CLOCK  700e3    // max 700kHz

#define ADC_CHANNELS  8    // 1 .. 8

#define SAMPLE_COUNT  16    // 16 samples for sliding average

int idata adc_input[ADC_CHANNELS];

void adc_conversion( void )

{

  static unsigned char channel;

  ADCF = (uchar)((int)0xFF00 >> ADC_CHANNELS);

  ADCLK = (uchar)(XTAL / ADC_CLOCK / 4 + 1);    // 11 * clock = 17æs

  EADC = 1;

  EA = 1;

  if( ++channel >= ADC_CHANNELS )

    channel = 0;

  ADCON = ADCON_SCH_ & (channel + 8 - ADC_CHANNELS) 

  | ADCON_ADEN_           // enable ADC

  | ADCON_PSIDLE_         // idle during conv.

  | ADCON_ADSST_;          // start conversion

  adc_input[channel] -= adc_input[channel] / SAMPLE_COUNT

         - (((uint)ADDH << 2) | (ADDL & 0x03));

}

void adc_interrupt( void ) interrupt INT_ADC

{

  ADCON &= ~(ADCON_PSIDLE_ | ADCON_ADEOC_ | ADCON_ADSST_);

            // clear  End of Conversion

}