adc.c

采用四端法测试欧姆电阻

#ifndef _ADC_C_
#define _ADC_C_

#include "c8051f000.h"
#include "adc.h"
#include "system.h"


//-----------------------------------------------------------------------------
// ADC0_Init
//-----------------------------------------------------------------------------
//
// Configure ADC0 to use Timer3 overflows as conversion source, to
// generate an interrupt on conversion complete, and to use left-justified
// output mode.  Enables ADC end of conversion interrupt. Leaves ADC disabled.
//

//-----------------------------------------------------------------------------
// ADC0_Init
//-----------------------------------------------------------------------------
//
// Configure ADC0 to use AD0BUSY as conversion source, to use left-justified
// output mode, to use normal tracking mode, and to measure the output of 
// the on-chip temperature sensor.  Disables ADC0 end of conversion interrupt
// and ADC0 window compare interrupt.
//
void fADC0_Init (void)
{
   ADC0CN = 0x80;                      // ADC0 enabled; normal tracking
                                       // mode; ADC0 conversions are initiated 
                                       // on write to AD0BUSY; ADC0 data is
                                       // left-justified
   REF0CN = 0x03;                      // disable temp sensor, on-chip VREF,
                                       // and VREF output buffer
   AMX0SL = 0x00;                      // Select channel 0  as ADC mux output
   ADC0CF = 0x80;		       //

   EIE2 &= ~0x02;                      // disable ADC0 EOC interrupt
   EIE1 &= ~0x04;                      // disable ADC0 window compare interrupt
}
//-----------------------------------------------------------------------------
// Interrupt Service Routines
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// ADC0_ISR
//-----------------------------------------------------------------------------
//
// ADC0 end-of-f ISR 
// Here we take the ADC0 sample, add it to a running total <accumulator>, and
// decrement our local decimation counter <int_dec>.  When <int_dec> reaches
// zero, we post the decimated result in the global variable <result>.
//
void fADC0_ISR (void) interrupt 15
{
   static unsigned int_dec=INT_DEC;    // integrate/decimate counter
                                       // we post a new result when
                                       // int_dec = 0
   static long accumulator=0L;         // here's where we integrate the
                                       // ADC samples             

   ADCINT = 0;									// clear ADC conversion complete
                                       // indicator

	accumulator += ADC0;                // read ADC value and add to running
                                       // total
   int_dec--;                          // update decimation counter

   if (int_dec == 0) {                 // if zero, then post result
      int_dec = INT_DEC;               // reset counter
      result = accumulator >> 12;
      accumulator = 0L;                // reset accumulator
   }
}



unsigned int fADConverter(unsigned char channel)
{	

	unsigned int adc_result = 0,temp;
	unsigned char i;

 //	AMX0SL = channel;  


	for(i=0;i<16;i++)
	{ 
		ADCINT = 0;                     // clear conversion complete indicator
      		ADBUSY = 1;                     // initiate conversion
      		while (ADCINT == 0);            // wait for conversion complete
      		adc_result = adc_result + ADC0L;            // read ADC0 data
		temp = ADC0H;
		temp = temp <<8;
		adc_result = adc_result + temp ;
	}

	adc_result = adc_result>>4;
//	adc_result = i-16;

	return(adc_result);
}



#endif