ads1110.c

该程序可以测量的电压误差为0.001V,精度高

// ************************************
// ADS1110 驱动
// 输出码 = -1 * 最小码 * PGA * (Vin+ - Vin-)/2048
// 配置寄存器: BIT	 	7		6	5	4	3	2		1		0
//		   	   NAME 	ST/DRDY 0	0	SC	DR1	DR0		PGA1 	PGA0
// ST/DRDY: 写1开始单周期转换   读数据时为0有新数据，为1是旧数据
// SC：为1时是单周期转换方式，为0时是连续转换方式
// 数据速率控制：DR1、DR0    00：240		01：60		10：30		11：15  （缺省设置）
// PGA：增益设置 PGA1、PGA0	 00：1			01：2		10：4		11：8
// ************************************
// 名称：-0.3 ~2.48v电压表
// 作者：黄煜龙
// 完成日期：2008-08-12
#include<at89x52.h>

sbit SDA = P1^1;
sbit SCL = P1^2;


sfr PortCode = 0x80;  // P0
sfr PortBit  = 0xa0;  // P2

unsigned char TMR1H;
unsigned char TMR1L;
unsigned char TMR2;

unsigned char code displaybit[9] = {
0x7f,0xbf,0xdf,0xef,0xf7,0xfb,0xfd,0xfe,0xff};           //数码管位分布(自左至右)

unsigned char code displaycode[] = {
0xfc,0x60,0xda,0xf2,0x66,0xb6,0xbe,0xe0,0xfe,0xf6};  //数码管字段0,1,2,3,4,5,6,7,8,9 

void delay_dis(unsigned int Ms)
{
	unsigned char i;
	
	for( ; Ms != 0; Ms-- )
	{
		for(i = 1; i != 0; i-- );	
	}

}

void Display(unsigned int dat,unsigned char DotPosition,unsigned char ClearZeroFlag)
{
	unsigned char i;

	for(i = 0; i != 8; i++)
	{ 	
		PortBit = 0xFF;    //消除重影

		if(i == DotPosition) // 小数点处理
		{
			PortCode = (displaycode[(dat%10)]|0x01);
		}
		else		PortCode = displaycode[dat%10];

		PortBit = displaybit[i];

		if(ClearZeroFlag&&(!dat)&&(i>DotPosition)) return;

		dat /= 10;
		delay_dis(255);	
	}
}

void delay_1(void)            //延时
{
	unsigned int j;
	for(j=5535;--j;) continue;
}


void IIC_Start(void)
{
	SDA = 1;
	SCL = 1;
	SDA = 0;
	SCL = 0;
}

void IIC_Stop(void)
{
	SDA = 0;
	SCL = 1;
	SDA = 1;		
}
unsigned char  IIC_Ask(bit i) // i 为1时是检查应答
{
	bit ask;
	if (i)
	SDA = 1;
	else
	SDA = 0;
	SCL = 1;
	ask = SDA;
	SCL = 0;	
	return ask;	
}

void SendByte(unsigned char dat)
{
	unsigned char i;

	for (i = 8; i != 0; i--)
	{
		SDA = (dat & 0x80);
		SCL = 1;
		dat <<= 1;
		SCL = 0;
	}
}

unsigned char ReadByte(void)
{
	unsigned char i,dat;

	dat = 0;
	SDA = 1;

	for (i = 8; i != 0; i --)
	{		
		SCL = 1;
		SCL = 1;
 		dat <<= 1;
		if (SDA)
		{
			dat++;
		}	
		SCL = 0;
	}
	return dat;	
}

void ADS110_Write(unsigned char outdat)
{
	IIC_Start();

	SendByte(0x94);			// ED0 0x90  	ED2  0x94

	while(IIC_Ask(1));       //等待应答	

	SendByte(outdat);

	while(IIC_Ask(1));       //等待应答

	IIC_Stop();
}

void ADS110_Read(void)
{
	IIC_Start();

	SendByte(0x95);

	while(IIC_Ask(0));       //等待应答	

	TMR1H=ReadByte();     // 读高8位
	IIC_Ask(0);              //连续读
	TMR1L=ReadByte();     //读低8位
	IIC_Ask(0);              //连续读
	TMR2=ReadByte();      //读配置字
	IIC_Ask(1);              

	IIC_Stop();
}


void main(void)
{
	unsigned int Volt,Rcnt;

	ADS110_Write(0x8C);
	delay_1();
	ADS110_Read();
	while(1)
	{
		if(Rcnt == 25)
		{
			ADS110_Read();
			Rcnt = 0;
		}
		Rcnt++;
		Volt=TMR1H*256;
		Volt|=TMR1L;
		if(Volt > 0xf000)	Volt = 0;	
		else if(2500>Volt) 	Volt+=30;
		else {Volt  += 10;Volt*=1.005;}


		Display(Volt/16,3,1);// 转换成电压值


	}
		
}