adc.c

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#include "t89c51cc02.h"

#include "datatypes.h"
#include "adc.h"

void ADC_init()
{
        ADCF=0x03;              /* set P1.0 as analog input */
        ADCON &= 0xF8;  /* clear A/D channel select */
        ADCON |= MSK_ADCON_ADEN; /* enable ADC */
}

WORD ADC(BYTE channel)
{
        WORD result=0;  

        ADCON &= 0xF8;  /* empty channel field */

        ADCON |= channel; /* set channel to measure */
        ADCON |= MSK_ADCON_ADSST; /* start A/D input */

        /* wait until conversion has finished  - inline assembler is faster */
        _asm
adcloop:
        mov A,_ADCON
        jb ACC.3,adcloop
        _endasm;

        ADCON &= 0xef;

        /* read A/D value */
        result=((ADDH<<2)+ADDL);
        
        return(result);
}

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