voltage_c52.c

用C52读AD977并转换成电压显示出来

#include "AT89X52.h"

#define AD977_DATACLK  	P1_0
#define AD977_DATA	P1_1
#define AD977_R_nC	P1_2
#define AD977_nBUSY	P1_3

#define SEG	p2
#define COM	P3


signed int read_ad(void);
void convert_display(signed int read_ad_data);
void display_negative(void);
void display_one_BCD(unsigned char bit_num , unsigned char d, bit s);

void main(void)
{
	signed int data read_ad_data=0,i;
	P0=0xff;
	P1=0xff;
	P2=0xff;
	while(1)
	{
		P3=0xff;
		read_ad_data = read_ad();
		//read_ad_data = 0x7fff;
		for (i=0;i<100;i++)
		convert_display(read_ad_data);
	}

}

signed int read_ad(void)
{
	signed int data temp=0;
	
	signed char i=16;
	
	AD977_DATACLK = 0;
	temp=0;
	AD977_R_nC=0;
//	while(AD977_nBUSY==0);
	AD977_R_nC=1;
	while(AD977_nBUSY==1);
	AD977_DATACLK=1;
	AD977_DATACLK=0;
 	while(i--)
	{
		AD977_DATACLK=1;
		temp = (temp<<1)|AD977_DATA;
		AD977_DATACLK=0;
	}
	return(temp);
}

void convert_display(signed int  read_ad_data)
{
	bit s = ( (read_ad_data&0x8000) == 0x8000) ;
	unsigned char data d,int_num=0;	
	signed char data bit_num=7;
//	bit dot = 0;
	float voltage;

	if(s==1)
	{
		display_negative();
		read_ad_data=(read_ad_data^0xffff)+1;
		//read_ad_data=read_ad_data&0x7fff;
		bit_num=6;
	}
	
// convert ad read data to voltage
	
	voltage=20.0*((unsigned int )read_ad_data)/65536.0;

//	if(voltage>=1.0) int_num=1;
//	else int_num=0;

	while(voltage >= 10.0)
	{
		voltage=voltage/10.0;
		int_num++;
	}
		

	while(bit_num>=0)
	{
		d=(int)voltage;
		voltage=(voltage-d)*10.0;
		if(int_num==0)
		{
			display_one_BCD(bit_num,d,1);
		}
		else
		{
			display_one_BCD(bit_num,d,0);
		}
		bit_num--;
		int_num--;
	}
}

void display_negative(void)
{
	P3=0xff;
	P2=~0X40;
	P3_7=0;
}

void display_one_BCD(unsigned char bit_num , unsigned char d, bit s)
{
	
	P3=0xff;

	switch(d)
	{
		case 0:
			if(s==1)
				P2=~0x0bf;
			else
				P2=~0x03f;
			break;
		case 1:
			if(s==1)
				P2=~0x86;
			else
				P2=~0x06;
			break;
		case 2:
			if(s==1)
				P2=~0x0db;
			else
				P2=~0x05b;
			break;
		case 3:
			if(s==1)
				P2=~0x0cf;
			else
				P2=~0x04f;
			break;
		case 4:
			if(s==1)
				P2=~0x0e6;
			else
				P2=~0x066;
			break;
		case 5:
			if(s==1)
				P2=~0x0ed;
			else
				P2=~0x06d;
			break;
		case 6:
			if(s==1)
				P2=~0x0fd;
			else
				P2=~0x07d;
			break;
		case 7:
			if(s==1)
				P2=~0x087;
			else
				P2=~0x007;
			break;
		case 8:
			if(s==1)
				P2=~0x0ff;
			else
				P2=~0x07f;
			break;
		case 9:
			if(s==1)
				P2=~0x0e7;
			else
				P2=~0x067;
	}

	switch(bit_num)
	{
		case 0:
			P3_0=0;	
			break;
		case 1:
			P3_1=0;	
			break;
		case 2:
			P3_2=0;	
			break;
		case 3:
			P3_3=0;	
			break;
		case 4:
			P3_4=0;	
			break;
		case 5:
			P3_5=0;	
			break;
		case 6:
			P3_6=0;	
			break;
		case 7:
			P3_7=0;	
	}
}