max6675.c

Application examples max6675Application examples max6675Application examples max6675

#include <reg51.h>
#include <stdlib.h>
#include <stdio.h>
#include "SVM12864_lcd.h"

#define uchar unsigned char
#define uint unsigned int
//--------------热电偶数字转换器MAX6675
sbit SO=P1^0;
sbit CS=P1^1;
sbit SCK=P1^2;

sbit P1_7=P1^7;
sbit P1_6=P1^6;

sbit P2_0=P2^0;
sbit P2_1=P2^1;

/*******************************************************
FUNCTION:delay_ms(uchar ntimes)
parameter: nTimes--延迟的毫秒数
cai 2006.05.20
*******************************************************/
void delay_ms(uchar ntimes)
{
   uchar i;
   for (i = 0; i<ntimes;i++)
   {
     TH0 = 256 - (1000/256);
     TL0 = 1000%256;
     TR0 = 1;
     while (!TF0);
     TF0 = 0;
   }
     TR0 = 0;
}
/**************************************************************
//FUNCTION:delay_ms(uchar ntimes)
//parameter: nTimes--延迟的微秒数
//sample:delay_ms(10);
//cai 2006.05.20
//*************************************************************/
void delay_us(uchar ntimes)
{
   TH0 = 0xFF;
   TL0 = 256 - ntimes;
   TR0 = 1;
   while (!TF0);
   TR0 = 0;
   TF0 = 0;   
}
/********************************
//读取MAX6675
*********************************/
int Read_6675()
{ uchar i;
  uint dat_temp; 
  uint dat_6675;
  i=0;
  dat_temp=0;
  dat_6675=0;
  //ready
  CS=0;
  //delay_us(10);
  SCK=0;
  //delay_us(10);
  //get D15-D0 from 6675
  for(i=0;i<16;i++)
  {	  
   SCK=1;  
   dat_temp=dat_temp<<1; 
   if(SO==1)
    dat_temp=dat_temp|0x01;
   SCK=0;
   //delay_us(10);
  }
  CS=1;
  dat_temp=dat_temp<<1;
  dat_temp=dat_temp>>4;
  dat_temp=dat_temp/4;
  dat_6675 = 	dat_temp;
  return dat_6675;
}
/* *******************************
//转换读取MAX6675的数据dat
*********************************/
void dat_cov(uint dat)
{
}

main()
{
uint j;
uint dat;
uint margin;
uchar i;
char a[16];
char smargin[16];

margin=0;
dat=0;
j=0;
margin=25;

//LCDRST=0;
for(i=0;i<5;i++) delay_ms(200);
//LCDRST=1;
LCD_Ini();
LCD_At(1);
LCD_Printf("Test clear CMD ..");
LCD_At(2);
LCD_Printf("Foracb!");
LCD_At(3);
LCD_Printf("The MRGN is 25`C");
 while(1)
  {
    LCD_At(4);
	//读取MAX6675的温度值
    dat=Read_6675();
	if(dat>=0)
	{
    sprintf(a,"T is %d`C",dat);
	LCD_Printf(a);
	}
	//低于MRGN/margin 警报！
	if(dat<=margin) P1_6=0;
	else P1_6=1;

	//键盘扫描 调整参数MRGN/margin
	P2_0=1;	//	用于调整参数MRGN/margin
	P2_1=1;	// 	用于调整参数MRGN/margin
	while(P2_0&&P2_1&&j<60000){j++;};
	if(P2_0==0) 
	{
	margin=margin-1;
	}
	else if(P2_1==0)
	{
	margin=margin+1;
	};
	if(j<60000)
	{
	LCD_At(3);
	sprintf(smargin,"The MRGN is %d`C",margin);
    LCD_Printf(smargin);
	for(i=0;i<80;i++) delay_ms(200);
	}
	j=0;
  }
}