adc.c

AVR atmega64串口驱动

#define adc_c
#include "main.h"



uint AdcConvert(uchar adc_input)
{
uint g_aAdValue[8];	//A/D转换缓冲区
	uchar i;
	uint ret;
	uchar max_id,min_id,max_value,min_value;
	
	ADMUX=(0xc0|adc_input);//内部2.56V参考电压，0通道
	ADCSRA|=_BV(ADEN);//使能ADC，单次转换模式
	//连续转换8次
	for(i=0;i<8;i++)
	{
		ADCSRA|=_BV(ADSC);
		_delay_loop_1(60);
		while(ADCSRA&_BV(ADSC))
			_delay_loop_1(60);
		ret=ADCL;
		ret|=(uint)(ADCH<<8);
		g_aAdValue[i]=ret;
	}
	ret=0;
	for(i=1;i<8;i++)
		ret+=g_aAdValue[i];
	
	//找到最大和最小值索引	
	ret/=7;
	max_id=min_id=1;
	max_value=min_value=0;
	for(i=1;i<8;i++)
	{
		if(g_aAdValue[i]>ret)
		{
			if(g_aAdValue[i]-ret>max_value)
			{
				max_value=g_aAdValue[i]-ret;
				max_id=i;
			}
		}
		else
		{
			if(ret-g_aAdValue[i]>min_value)
			{
				min_value=ret-g_aAdValue[i];
				min_id=i;
			}
		}
	}
	
	//去掉第一个和最大最小值后的平均值
	ret=0;
	for(i=1;i<8;i++)
	{
		if((i!=min_id)&&(i!=max_id))
			ret+=g_aAdValue[i];     
	}
	if(min_id!=max_id)
		ret/=5;
	else  
		ret/=6;

//	ADCSRA=0;//关闭ADC
	
	return ret;
}