wds18b20.#2

C8051F.rar

//参考程序A: 程序名WDS18B20.C  数字温度传感器DS18b20测温实验:P0.0连接SDA,   P0.1`连接SCL.     SAA1064驱动四位数码管显示温度值:< 0 1 3. 4>
#include <c8051f020.h>                    // SFR declarations
#include <intrins.h>
#define  WRITE       0x00                 // 写位
#define  READ        0x01                 // 读位
#define  CHIP_B      0x70      //   SA1064地址
#define  SMB_START  0x08      // 主收发器发送起始位成功.再将从机写地址送SMB0DAT
#define  SMB_MTADDACK  0x18 //(MT) 主收发器发送从地址＋W成功；收到 ACK(从机应答)
#define  SMB_MTDBACK  0x28   // (MT) 主收发器发送数据字节成功；收到ACK(从机应答)
#define  SMB_MRADDACK 0x40 // (MR) 主收发器发送从地址＋R成功；收到 ACK(从机应答)
#define  SMB_MRADDNACK  0x48  //主收发器发送从地址＋R成功；收到NACK(从机无应答)
#define  SMB_MRDBACK    0x50   // (MR) 主收发器接收数据成功；
 #define  SMB_MRDBNACK   0x58   // (MR) 主收发器接收数据成功；
 char COMMAND;          // 保存从地址加读/写位，用在中断服务程序SMBus ISR中
char WORD;              // 保存在SUMBUS总线上传送的数或刚被接受到的数据。
unsigned char totalnumber,sendnumber;   
unsigned char xdata  OP_CODE;  
unsigned char xdata SENDMODE;  
bit SM_BUSY;  //该位在开始接收数据或发送数据时被置位。在中断完成后被清0
sbit DataPortDS1820 = P0^2;   //1 WIRE	用P0.2这一条信号线
unsigned char wr_data[8];     //数组wr_data[8]中存放要写入SAA1064的数据
unsigned char rd_data[8];     //数组rd_data[8]中存放从DS18B20中读出的数据
void Delay1us(unsigned char us)  //延时
{
	while (us)
	{
		_nop_(); _nop_(); _nop_(); _nop_(); _nop_();
		--us;
	}
}
void Delay15us(void)  
{
	Delay1us(15);                  //延时15秒
}
void Delay10us(void)
{	
	Delay1us(10);
}
bit RstDS1820(void)		//返回0-有设备连接1-无设备连接
{
	unsigned char i;
	bit RstFlag;
	RstFlag=1;	
	DataPortDS1820=0;
	for (i=0;i<40;i++)      	//480us 延时
		Delay15us(); 
	DataPortDS1820=1;
	for(i=0;i<4;i++)			//15us-60us 延时
	{
		Delay15us();
	}
	for (i=0;i<16;i++)			//60us-240us 延时
	{
		Delay15us();
		if (DataPortDS1820==0) RstFlag=0;
	}
	for (i=0;i<16;i++)			//240us
	{
		Delay15us();
	}
	return RstFlag;	
}
void WriteDS1820(unsigned char ch)
{
unsigned char i;
	DataPortDS1820=1;
	Delay1us(1);
	for (i=0;i<8;i++)
	{
		EA=0;
		DataPortDS1820=0;
		Delay15us();
		DataPortDS1820=ch&0x1;
		EA=1;
		Delay15us();Delay15us();Delay15us();
		DataPortDS1820=1;
		ch=ch>>1;
		Delay1us(1);
	}
}
unsigned char ReadDS1820(void)
{
	unsigned char i,ch;
	ch=0;
	DataPortDS1820=1;
	Delay1us(1);
	for (i=0;i<8;i++)
	{
		EA=0;
		DataPortDS1820=0;
		Delay10us();
		DataPortDS1820=1;
		Delay1us(2);
		ch=ch>>1;
		if (DataPortDS1820==1)
		{
			ch=ch+0x80;
		}
		EA=1;
		Delay15us();Delay15us();Delay15us();
	}	
	return ch;
}
void SkipROMCode(void)       //主机发跳过读序列号的操作命令:0xcc
{
	RstDS1820();
	WriteDS1820(0xcc);
}
void StartADC(void)
{
	RstDS1820();			//复位
	WriteDS1820(0xcc);		//广播
	WriteDS1820(0x44);		//启动温度转换转换 12bit700ms
}
unsigned int GetTempValue(void)//读取温度值的程序
{
	unsigned char i,j;        
	unsigned int T;
	SkipROMCode();
	WriteDS1820(0xBE);  //发布读取温度值的命令(0xBE)
	i=ReadDS1820();
	j=ReadDS1820();
	StartADC();
	T=i+j*256;
	if (T==0xffff) return 0xffff;
	if (T>0x8000)                      //温度为负号
	{
		T=-T;
		return(0x8000+T*5/8);          //计算温度值
	}
	else                               //温度为正号
		return(T*5/8);
}
void sleep_ms(unsigned int count)      //延时
{
	unsigned char ii,jj;
	for(ii=0;ii<count;ii++)
	{
		for(jj=0;jj<250;jj++)
		_nop_();
	}
}
void SYSCLK_Init (void)                 // 时钟初始化
{
	int i;								// 延时计数器
	OSCXCN = 0x67;						// 启动外部晶振(11.0592MH)
	for (i=0; i < 256; i++);			// 等待外部晶振稳定
	while (!(OSCXCN & 0x80));		
	OSCICN = 0x88;						// 选择外部晶振,允许时钟丢失检测
}
void PORT_Init (void)
{
	XBR0    = 0x01;                     // 允许 SMBus,P0.0-SDA,P0.1--SCL
	XBR2	= 0x40;						// 使能交叉开关和弱上拉
}
void SLA_SEND(char chip_select, char *wr_data, char number)
{
   SENDMODE=0x01;
   totalnumber=number;
   sendnumber=number;
   while(SM_BUSY);                        //  SMBus 忙碌则等待
   SM_BUSY = 1;                           // SMBus 忙碌标志置1
   SMB0CN = 0x44;                         // 允许SMBus , ACK 应答信号为低
   COMMAND = (chip_select | WRITE);       // COMMAND = 7位地址加读/写位
   STO = 0;
   STA = 1;                               // 数据传送开始
	while(SM_BUSY);   
}
void Init18b20(void)
{
	SkipROMCode();                        //主机发跳过读序列号的操作命令:0xcc
	WriteDS1820(0x44);                    //启动温度转换
}
void main (void) 
{
	unsigned char temp;
	unsigned int w;
   unsigned char data Number[16]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
	WDTCN = 0xde;
	WDTCN = 0xad;                        //关看门狗
	SYSCLK_Init ();                      //初始化时钟
	PORT_Init ();                        //初始化IO口
	Init18b20();
   SMB0CN = 0x44;                         // 使能 SMBus ,应答低电平(AA = 1)
   SMB0CR = 0xc9;                 // SMBus 速率 = 100 kHz(系统时钟:11.0592MHZ)
   EIE1 |= 2;                             // SMBus 中断使能
   SM_BUSY = 0;                           // 释放总线,为第一次传送.
   SI = 0;
	EA=1;				                	//开中断
	for (;;)
	{
		sleep_ms(250);
		sleep_ms(250);
		sleep_ms(250);
		w = GetTempValue();            //读出温度值的原始数据存入W
		wr_data[0] = 0x00;             //将SAA1064的子地址存入数组wr_data[0]
		wr_data[1] = 0x17;             //将SAA1064的命令存入数组wr_data[1]
		wr_data[2] = 0x3f;
		temp = (w%1000)/100;           //计算温度值   十位
		wr_data[3] = Number[temp];     //查表,得到要显示的子型码
		temp = (w%100)/10;             //个位
		wr_data[4] = Number[temp]|0x80;//查表,得到要显示的子型码,再加小数点
		temp = (w%10);                 //小数位
		wr_data[5] = Number[temp];
		SLA_SEND(CHIP_B,wr_data,0x06);//向SAA1064送出6位数:00,17H 加四位温度值
		sleep_ms(250);
		sleep_ms(250);
		_nop_();
		sleep_ms(250);
		sleep_ms(250);
	}
}
void SMBUS_ISR (void) interrupt 7
{  
   switch (SMB0STA){                    // 判别SUMBUS状态码(SMB0STA 寄存器)
      case SMB_START:	                //SMB0STA=0x08
         SMB0DAT = COMMAND ;			// 装入从地址
                                        
         STA = 0;                       // 人工清除启动位
         SI = 0;                        // 清除中断标志位
         break;
     case SMB_MTADDACK:	//SMB0DAT=0x18
         SMB0DAT = wr_data[0];
         SI = 0;                        // 清除中断标志位
         break;
      case SMB_MTDBACK:		            //SMB0DAT=0x28
         switch (SENDMODE){         	//检查低四位
            case 1:
			   sendnumber--;
			   if(sendnumber)
			   SMB0DAT = wr_data[totalnumber-sendnumber];
			   else{
			   		STO=1;
				   	SM_BUSY=0;
				}
          break;                   
            case 0:
			     STO = 0;
               STA = 1;
               break;                         
            default:                     
               STO = 1;
               SM_BUSY = 0;
               break;
         }
         SI = 0;
         break;
      case SMB_MRADDACK:	//SMB0DAT=0x40
         AA = 0;                          // 主机送AA = 0;
         SI = 0;                          //清除中断标志位
         break;
      case SMB_MRADDNACK:	//SMB0DAT=0x48
         STO = 0;
         STA = 1;
         SI = 0;
         break;
      case SMB_MRDBACK:		//SMB0DAT=0x50
         STO = 1;
         SM_BUSY = 0;
         SI = 0;
         break;
      case SMB_MRDBNACK:	//SMB0DAT=0x58
         rd_data[0] = SMB0DAT;
         STO = 1;
         SM_BUSY = 0;
         AA = 1;           // AA=1,准备下一次传输
         SI = 0;
         break;
          default:
         STO = 1;
         SM_BUSY = 0;
         break;
      }
}