adc.c.130216224150

ATmega16-ad1602

#define ADC_C
#include "includes.h"
#define MaxAdcBufSize 9
#define AdcBufStep 3 //为了算巴士均值

static volatile unsigned int ADCBuffer[MaxAdcBufSize];

/******************************************************************************/
unsigned char  adc_mux = 0x00;//选择通道:ADC0

unsigned int ReadADC(void)
{
 	return ADCBuffer[0];
}

void init_adc(void)
{	
	DDRA&=~BIT(PA0);
	PORTA&=~BIT(PA0);
    ADCSRA = 0x00; 
    ADMUX =(1<<REFS0)|(adc_mux&0x1f);  	 //AVCC,AREF引脚加滤波电容,单端输入ADC0
    ADCSRA=(1<<ADEN)|(1<<ADSC)|(1<<ADIE)|(1<<ADPS2)|(1<<ADPS1) ;//64分频
}

/******************************************************************************/

/******************************************************************************/
//ADC完成中断
//#pragma vector = interrupt_handler adc_isr:iv_ADC  
// define the interrupt handler

#pragma interrupt_handler adc_isr:15  
void adc_isr(void)
{     
 
//**************************************************************	
	unsigned char i;
	unsigned int tmp,sum=0;
	tmp=ADCL;
	tmp=tmp+ADCH*256; 
	 	 
	for(i=1;i<MaxAdcBufSize -1;i++)
	{
  	 	ADCBuffer[i]=ADCBuffer[i+1];
  	    sum+=ADCBuffer[i];
	}
  	ADCBuffer[MaxAdcBufSize-1]=tmp;
  	sum+=ADCBuffer[MaxAdcBufSize-1];
  	ADCBuffer[0]=(sum>>AdcBufStep);
//****************************************************************	              
	
	ADMUX|=(adc_mux&0x1f)|(1<<REFS0);
    ADCSRA|=(1<<ADSC);//启动AD转换
}