AD/DA轉換（程式）

#include <reg52.h>
#include "./delay/delay.h"


#define LCD_WRITE_DATA 1
#define LCD_WRITE_COM 0
#define LCDPORT P0
#define SUCC 0
#define ERR 1


sbit RS = P2^4;
sbit RW = P2^5;
sbit E = P2^6;


sbit SCL = P1^0;
sbit SDA = P1^1;
bit ack = 0;


void iic_start()
{
		SDA = 1;
		SCL = 1;
		delay_us(1);
		SDA = 0;
		delay_us(1);
		SCL = 0;
}


void iic_stop()
{
		SDA = 0;
		SCL = 1;
		delay_us(1);
		SDA = 1;
		delay_us(1);
		SCL = 0;


}


bit iic_send_byte(unsigned char byte)
{
		unsigned char i;
		SDA = 1;
		for(i = 0;i < 8;i++)
		{
				SDA = byte & 0x80;
				SCL = 1;
				delay_us(1);
				SCL = 0;
				byte <<= 1;
		}
		SCL = 1;
		SDA = 1;
		delay_us(1);
		if(0 == SDA)
		{
				ack = 1;
		}
		else
		{
				ack = 0;
		}
		SCL = 0;
		return ack;
}


void iic_noack()
{
		SDA = 1;
		SCL = 1;
		delay_us(1);
		SCL = 0;
}


void iic_ack()
{
		SDA = 0;
		SCL = 1;
		delay_us(1);
		SCL = 0;
}


unsigned char iic_rcv_byte()
{
		unsigned char i;
		unsigned char temp = 0;
		unsigned char a;
		SDA = 1;
		for(i = 0;i < 8;i++)
		{
				SCL = 0;
				delay_us(1);
				SCL = 1;
				if(SDA == 1)
				{
						a = 0x01;
				}
				else
				{
						a = 0x0;
				}
				temp |= (a<<(7-i));
				delay_us(1);
		}	
		SCL = 0;
		return temp;
}


unsigned char AT24C02_send_str(unsigned char devaddr,unsigned char romaddr,unsigned char *s,unsigned char num)
{
		unsigned char i;
		iic_start();
		iic_send_byte(devaddr);
		if(0 == ack) return ERR;
		iic_send_byte(romaddr);
		if(0 == ack) return ERR;
		for(i = 0;i < num;i++)
		{
				iic_send_byte(*s);
				if(0 == ack) return ERR;
				s++;
		}
		iic_stop();
		return SUCC;


}


unsigned char AT24C02_rcv_byte(unsigned char devaddr,unsigned char romaddr,unsigned char *s,unsigned char num)
{
		unsigned char i;
		iic_start();
		iic_send_byte(devaddr);
		if(0 == ack) return ERR;
		iic_send_byte(romaddr);
		if(0 == ack) return ERR;
		iic_start();
		iic_send_byte(devaddr + 1);
	
		for(i = 0;i < num - 1;i++)
		{
				*s = iic_rcv_byte();
				iic_ack();
				s++;


		}
		*s = iic_rcv_byte();
		iic_noack();
		iic_stop();
		return SUCC;
}




void lcd1602_write_data(unsigned char byte,unsigned char flag)
{
		if(flag)
		{
				RS = 1;
		}
		else
		{
				RS = 0;
		}
		RW = 0;
		E = 1;
		LCDPORT = byte;
		delay_us(5);
		E = 0;
}


void lcd_init()
{
		delay_ms(15);
		lcd1602_write_data(0x38,LCD_WRITE_COM);
		delay_ms(5);
		lcd1602_write_data(0x38,LCD_WRITE_COM);
		delay_ms(5);
		lcd1602_write_data(0x38,LCD_WRITE_COM);
		delay_ms(5);
		lcd1602_write_data(0x38,LCD_WRITE_COM);
		delay_ms(5);
		lcd1602_write_data(0x08,LCD_WRITE_COM);
		delay_ms(5);
		lcd1602_write_data(0x01,LCD_WRITE_COM);
		delay_ms(5);	
		lcd1602_write_data(0x06,LCD_WRITE_COM);
		delay_ms(5);
		lcd1602_write_data(0x0c,LCD_WRITE_COM);
		delay_ms(5);
}


void lcd_write_str(unsigned char x,unsigned char y,unsigned char *p)
{
		if((x > 15) || (y > 1))
		{
				return;
		}
		if(0 == y)
		{
				lcd1602_write_data(0x80+x,LCD_WRITE_COM);
		}
		else
		{
				lcd1602_write_data(0x80+0x40+x,LCD_WRITE_COM);
		}


		while(*p != '\0')
		{
			  lcd1602_write_data(*p,LCD_WRITE_DATA);		
				p++;
		}
}


unsigned char AD_read()
{
	unsigned char temp;	
	iic_start();
	iic_send_byte(0x90);
	if(0 == ack) return ERR;
	iic_send_byte(0x40);
	iic_start();
	iic_send_byte(0x90+1);
	if(0 == ack) return ERR;
}
	temp = iic_rcv_byte();
	iic_noack();
	iic_stop();
	return temp;




void lcd_dis_char(unsigned char x, unsigned char y, unsigned char byte)
{
    if((x > 15) || (y > 1))
		{
			  return ;
		}
		if(0 == y)
		{
			  lcd1602_write_data(0x80 + x,LCD_WRITE_COM);
		}
		else
		{
			  lcd1602_write_data(0x80 + 0x40 + x,LCD_WRITE_COM);
		}
		lcd1602_write_data(byte,LCD_WRITE_DATA);
}


unsigned char DA_write(unsigned char num)
{
		iic_start();
		iic_send_byte(0x90);
		if(0 == ack) return ERR;
		iic_send_byte(0x40);
		if(0 == ack) return ERR;
		iic_send_byte(num);
		if(0 == ack) return ERR;
		iic_stop();
		return SUCC;
}


void main()
{
		unsigned char num;
		unsigned char test;
		unsigned char v;
		lcd_init();
		
    while(1)
		{
				test = AD_read();
				v = test*100 / 51; 
				lcd_dis_char(0,0,(test/100)+0x30);
				lcd_dis_char(1,0,(test%100/10)+0x30);
				lcd_dis_char(2,0,(test%10)+0x30);
				lcd_dis_char(0,1,(v/100)+0x30);
				lcd_dis_char(1,1,'.');
				lcd_dis_char(2,1,(v%100)/10+0x30);
				lcd_dis_char(3,1,(v%10)+0x30);
				DA_write(num);
				num++;
				delay_ms(2);
		}


		
		
}