温度传感器DS18B20驱动程序.docx

1、温度传感器DS18B20驱动程序#include ds18b20.h#include #if 0/*FUNCTION NAME: InitDS18b20 *CREATE DATE: 2009/11/12 *CREATED BY: XS *FUNCTION: 复位DS18B20和检测存在脉冲 *MODIFY DATE: 2009/11/12 *INPUT: 无 *RETURN: 初始化成功，返回1，否则返回0 */ BOOL InitDs18b20(void) BOOL flag = FALSE; BIT bt; bt = ET0; ET0 = 0; DQ = 1; Delay70us(1);

2、/稍作延时 DQ = 0; / 复位 Delay70us(8); /精确延时大于480us DQ = 1; /拉高总线,等待存在脉冲 Delay70us(1); / 60-75us之间 if(0=DQ) flag = TRUE; Delay70us(8); / 复位后大于480us延时 ET0 = bt; return flag;/*FUNCTION NAME: ReadByte *CREATE DATE: 2009/11/12 *CREATED BY: XS *FUNCTION: 从DS18B20中读取一个字节的数据 *MODIFY DATE: 2009/11/12 *INPUT: 无 *R

3、ETURN: 读取的数据 */ UCHAR ReadByte(void) UCHAR i; UCHAR dat = 0; BIT bt; bt = ET0; ET0 = 0; for (i=0;i= 1; DQ = 0; Delay5us(); DQ = 1; Delay5us(); if(1=DQ) dat |=0x80; Delay70us(1); ET0 = bt; return(dat);/*FUNCTION NAME: WriteByte *CREATE DATE: 2009/11/12 *CREATED BY: XS *FUNCTION: 向DS18B20中写入一个字节的数据 *M

4、ODIFY DATE: 2009/11/12 *INPUT: 写入的数据 *RETURN: 无 */ void WriteByte(UCHAR wDat) UCHAR i; BIT bt; bt = ET0; ET0 = 0; for (i=0; i= 1; ET0 = bt;/*FUNCTION NAME: ReadDs18b20 *CREATE DATE: 2009/11/12 *CREATED BY: XS *FUNCTION: 从DS18B20储存器中读取多字节数据 *MODIFY DATE: 2009/11/12 *INPUT: 读取数据存入的地址和需要读取数据的数量 *RETURN

5、: 无 */ void ReadScrat(UCHAR *prDat,UCHAR num) UCHAR i; for(i=0;i=ERR_COUNTER) / 连续3次初始化失败，即认为DS18B20出现故障 return 0; WriteByte(SKIP_ROM); / 跳过读序号列号的操作 WriteByte(CONVERT_T); / 启动温度转换 Delay70us(20); / 延时至少500us，以供温度转换 while(1) if(InitDs18b20() counter = 0; break; else counter+; if(counter=ERR_COUNTER) /

6、 连续3次初始化失败，即认为DS18B20出现故障 return 0; WriteByte(SKIP_ROM); /跳过读序号列号的操作 WriteByte(READ_SCRAT); /读取温度寄存器等（共可读9个寄存器） ReadScrat(tempBuff, 9); if(0=CRC8(tempBuff,9) if(0=(tempBuff1&0x80) /为正温度 tempDat = (tempBuff1&0x07)*0x100 + tempBuff0; else tempDat = (0xFF-tempBuff1)&0x07)*0x100 + (0x100-tempBuff0); tem

7、pDat = -tempDat; *prTemperature = tempDat * 0.0625; return TRUE; return FALSE; /*FUNCTION NAME: GetDS18B20Temperature *CREATE DATE: 2009/8/17 *CREATED BY: XS *FUNCTION: 采样3次求均值作为温度值 *MODIFY DATE: 2009/8/17 *INPUT: 温度储存的地址 *RETURN: 正常为1，故障为0 */ BOOL GetDS18B20Temperature(float *pgTemperature) UCHAR i

8、; UCHAR counter = 0; float tempDat = 0; float tempVal = 0; for(i=0;i=ERR_COUNTER) /连续10次温度采样错误，则判断为故障，并返回 return FALSE; *pgTemperature = tempVal / 3;/ SendStr(boxTemp:);/ print(*pgTemperature ,1);/ SendChar(n); return TRUE;/*FUNCTION NAME: CRC8 *CREATE DATE: 2009/8/17 *CREATED BY: XS *FUNCTION: CRC效

9、验 *MODIFY DATE: 2009/8/17 *INPUT: 需要效验的数据地址和个数 *RETURN: 效验结果 */ UCHAR CRC8(UCHAR *point,UCHAR CRClen) /效验成功则crc返回0 UCHAR i,j,crc_8,crcbuff; crc_8 = 0; for(i=0; iCRClen; i+) crcbuff=*point+; for(j=0;j= 1; else crc_8 = 0x18; crc_8 = 1; crc_8 |= 0x80; crcbuff = 1; return crc_8; /*FUNCTION NAME: Delay5u

10、s *CREATE DATE: 2009/8/17 *CREATED BY: XS *FUNCTION: 延时5us *MODIFY DATE: 2009/8/17 *INPUT: 无 *RETURN: 无 */ void Delay5us(void)/ UCHAR i; / for(i=0;i7;i+); _nop_(); _nop_(); #endif/*FUNCTION NAME: Delay70us *CREATE DATE: 2009/8/17 *CREATED BY: XS *FUNCTION: 延时70us *MODIFY DATE: 2009/8/17 *INPUT: 次数 *RETURN: 无 */ void Delay70us(UCHAR timers) UCHAR i,j; for(j=0;jtimers;j+) for(i=0;i22;i+) / Delay5us(); _nop_(); _nop_(); _nop_();