stest.c

我自己写的ds1820b温度测量程序

#include <AT89X51.h>
#include <intrins.h>


#define TMPort P1_7

unsigned char MYWD[7]={0,0,0,0,0,'`','C'},DS1820ERR[]="NO DS1820!",TMCL[]={"TMCL"};
unsigned char disbuf[10]={0};
unsigned char trance=0,recived=0,comno=0,comzf;//发送状态、接受命令字符序号、接收的字符

unsigned int t;
bit DS1820ON,readtm;//DS1820响应、是否接收测温命令。

void initUart(void)//波特率9600，24M时钟
{
 TMOD|=0x20;
 SCON=0x50;
 PCON|=0x80;
 TH1=0xf3;
 TL1=0xf3;
 TR1=1;
 ES=1;
}


void uart(void) interrupt 4
{
unsigned char m=0; 
if(RI)
	{comzf=SBUF;RI=0;recived=1;}
else
    {TI=0;trance=1;}    
}


void Delay_110(void)	//延时110微秒，24M晶振
{EA=0;
#pragma asm
	MOV R0,#34H
	MOV R1,#02H
	TSR2:
	DJNZ R0,TSR2
	MOV R0,#34H
	DJNZ R1,TSR2
#pragma endasm
EA=1;}

void Delay_510(void)	//延时510微秒，24M晶振
{EA=0;
#pragma asm
    nop
	nop
	MOV R0,#7DH
	MOV R1,#04H
	TSR1:
	DJNZ R0,TSR1
	MOV R0,#7DH
	DJNZ R1,TSR1
#pragma endasm
EA=1;}

void InitDS1820(void)		//初始化DS1820
{  EA=0;
	TMPort = 1;		//拉高TMPort
	_nop_();//保持一个周期
    _nop_();
	TMPort = 0;		//拉低TMPort
    Delay_510();  //延时  DS1820复位时间要500us的低电平
    TMPort = 1;   //拉高TMPort
	Delay_110();  //延时110us 等待DS1820回应
  if (!TMPort)  //回应信号为低电平
    {DS1820ON=1;}
  else
    {DS1820ON=0;}
  Delay_110();  //延时
  Delay_110();
  TMPort=1;   //拉高TMPort
EA=1;
}


void ds1820command(unsigned char a) //写ds1820命令函数。
{
EA=0;
#pragma asm
  MOV A,R7
  MOV R2,#8
  CLR C
  WR1:
  CLR TMPort
  MOV R3,#2//延时3us,24M时钟
  DJNZ R3,$
  RRC A
  MOV TMPort,C
  MOV R3,#68//延时70us
  DJNZ R3,$
  SETB TMPort
  NOP
  NOP
  NOP
  NOP
  DJNZ R2,WR1
  SETB TMPort
#pragma endasm
EA=1;}

void ds1820rd(unsigned char *pt)//读ds1820数据
{
EA=0;
#pragma asm
MOV R4,#9
MOV A,R1
MOV R0,A
RD18201:
  MOV R2,#8
     RD18202:
       	SETB TMPort
	   	NOP//延时2us,24M时钟
		NOP
		NOP
		NOP
		CLR TMPort//写时间片开始
		NOP//延时2us,24M时钟
		NOP
		NOP
		NOP
		SETB TMPort//置为高电平，准备输入数据
		MOV R3,#10//延时11us,24M时钟
  		DJNZ R3,$
		MOV C,TMPort
		RRC A
		MOV R3,#48//延时50us,24M时钟
  		DJNZ R3,$
		DJNZ R2,RD18202
	MOV @R0,A
	INC R0
	DJNZ R4,RD18201
#pragma endasm
EA=1;}

void tmtoc (void)
{
unsigned char sign;//符号、实际温度的10倍整数
int tm; //实际温度的10倍
sign=disbuf[1]&0x20;
if (sign)//disbuf[1]高五位为符号位，判断符号根据补码存储方式，得出真实温度
	{disbuf[0]=~disbuf[0];//精确到0.1度，四舍五入
	 disbuf[1]=~disbuf[1];
	 tm=((int)disbuf[1]*256+(int)disbuf[0]+1)*0.625+0.5;}
else tm=((int)disbuf[1]*256+(int)disbuf[0])*0.625+0.5;
//tmof10=(int)tm;//输出温度各位的ASCii码

if (tm>=1000) MYWD[0]='1';	 
	 else if (sign) MYWD[0]='-';
	 	  else MYWD[0]='+';

MYWD[1]=tm/100%10+'0';
if (MYWD[0]=='0'&&MYWD[1]=='0')MYWD[1]='\0';
MYWD[2]=tm/10%10+'0';
MYWD[3]='.';
MYWD[4]=tm%10+'0';
}

void disp(char *p,unsigned char m) //输出一个字符数组,p为数组名，m为字符个数
{
unsigned char i;
    i=EA;
	EA=1;
	for(;*p!=0&&m!=0;p++,m--)
	{
		SBUF=*p;
		while(trance==0);
		trance=0;
	}
	EA=i;
}


void TMCLSHOW(void)
{
InitDS1820();//发出启动转化温度指令：初始化、skiprom、启动转化
if (!DS1820ON) {disp(DS1820ERR,12);}
ds1820command(0xCC);
ds1820command(0x44);
TMPort=1; 

for (t=0;t<1500;t++) Delay_510();//等待转化过程完成
InitDS1820();//读RAM中数据：初始化、skiprom、读命令、保存数据
ds1820command(0xcc);
ds1820command(0xbe);
ds1820rd(disbuf);
//disp(disbuf,9);
tmtoc();
disp("NOW,temperature is:",20);
disp(MYWD,7);
disp("\n",1);
}

void main(void)
{
DS1820ON=0;          //DS1820是否存在             
initUart();
InitDS1820();//发出启动转化温度指令：初始化、skiprom、启动转化
if (!DS1820ON) {disp(DS1820ERR,12);}
P1=0x55;
TMCLSHOW();
P1=0x33;
EA=1;
while (1)
 if (recived==1)//判断是否为温度测量命令
    {if(comzf==TMCL[comno])
	  {comno++;
	  if (comno>3)
	    {comno=0;
		TMCLSHOW();
		}
	  }
	else comno=0; 
	recived=0;
	}
}