DS18B20的分时读取，适合于操作系统，释放资源，不用在一次读取中来完成整个操作。一次读取中的延时等待，实在太消耗时间

#include "DS18B20.h" #define DS18B20_OUT_H() (GPIOB->BSRR=GPIO_Pin_5) //输出高 #define DS18B20_OUT_L() (GPIOB->BRR=GPIO_Pin_5) //输出低 //#define AM2305_IN_X (GPIOB->IDR&GPIO_Pin_5) // 对应端口输入寄存器 #define DS18B20_DQ_IN GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_5) #define DisRequset_STU 0//收到通信请求 #define EnableRequest_STU 1//收到通信请求 #define StartRST_STU 2//起始+复位信号 #define StartWriteCC_STU 3//启动转换 #define WriteRST_STU 4//启动转换后复位信号 #define WriteCC_STU 5//读取命令 #define ReadTemp_STU 6// 读取2个字节数据 #define ReadOK_STU 7// 读取完毕 #define WriteData44_STU 1// #define WriteDatabe_STU 2// u8 R_DS18B20_WBCnt = 0; u8 R_DS18B20_ComuTime = 0; u8 R_DS18B20_TempL = 0; u8 R_DS18B20_TempH = 0; u8 R_DS18B20_Bytecnt = 0; u8 R_DS18B20_Data = 0; u8 R_DS18B20_State = 0; u8 R_DS18B20_Request = 0; u8 R_WriteDS18_State = 0; u8 R_DS18B20_WDataBak = 0; u8 R_GotTemp = 0; static void DS18B20_IO_OUT(void) { // GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; // GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; // GPIO_Init(GPIOE, &GPIO_InitStructure); GPIO_OutConfigInit(PortB,PB5_AM2302_DATA); //推挽输出 } static void DS18B20_IO_IN(void) { // GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; // GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; // GPIO_Init(GPIOE, &GPIO_InitStructure); GPIO_InConfigInit(PortB,PB5_AM2302_DATA); //上拉输入 } void Ds18B20_ReadDate_RT(void) { u8 i = 0; if(!R_DS18B20_State ) return; if(R_DS18B20_State == EnableRequest_STU) { R_DS18B20_State = StartRST_STU; DS18B20_IO_OUT(); } switch(R_DS18B20_State) { case StartRST_STU: case WriteRST_STU: { R_DS18B20_ComuTime++; if(R_DS18B20_ComuTime <65) { DS18B20_OUT_L(); //拉低DQ 拉低650us } else { DS18B20_IO_IN(); if(R_DS18B20_ComuTime > 75) { if(!(DS18B20_DQ_IN)) { i= 0x55; } if(R_DS18B20_ComuTime > 90) //等待DS18B20响应 { R_DS18B20_ComuTime = 0; if(R_DS18B20_State == StartRST_STU) R_DS18B20_State = StartWriteCC_STU; if(R_DS18B20_State == WriteRST_STU) R_DS18B20_State = WriteCC_STU; } } } break; } case StartWriteCC_STU: //写入 cc 44 case WriteCC_STU: //写入 cc be { u8 Wstate = 0; if(R_WriteDS18_State == 0) { Wstate = DS18B20_Write_Byte(0xcc); //if(DS18B20_Write_Byte(u8 0xcc)) if(Wstate) { if(R_DS18B20_State == StartWriteCC_STU) R_WriteDS18_State = WriteData44_STU; if(R_DS18B20_State == WriteCC_STU) R_WriteDS18_State = WriteDatabe_STU; } } else { if(R_WriteDS18_State == WriteData44_STU) { if(DS18B20_Write_Byte(0x44)) { R_DS18B20_State = WriteRST_STU; DS18B20_IO_OUT(); R_WriteDS18_State = 0; } } else if(R_WriteDS18_State == WriteDatabe_STU) { if(DS18B20_Write_Byte(0xbe)) { R_DS18B20_State = ReadTemp_STU; R_WriteDS18_State = 0; R_DS18B20_Bytecnt = 0; R_DS18B20_Data = 0; R_DS18B20_WBCnt = 0; } } } break; } case ReadTemp_STU: { DS18B20_Read_Temp(); break; } default: break; } } //写一个字节到DS18B20 //dat：要写入的字节 u8 DS18B20_Write_Byte(u8 wdata) { if(R_DS18B20_ComuTime > 7) { R_DS18B20_ComuTime = 0; R_DS18B20_WBCnt++; if(R_DS18B20_WBCnt < 8) { R_DS18B20_WDataBak >>=1; } else { R_DS18B20_WBCnt = 0; return 1; } } R_DS18B20_ComuTime++; if(!R_DS18B20_WBCnt) { R_DS18B20_WDataBak = wdata; DS18B20_IO_OUT(); } if(R_DS18B20_WDataBak&0x01)//先发低位 { if(R_DS18B20_ComuTime < 2) DS18B20_OUT_L(); // Write 1 else DS18B20_OUT_H(); } else { if(R_DS18B20_ComuTime < 7) //写入50us低 DS18B20_OUT_L(); // Write 0 else DS18B20_OUT_H(); } return 0; } //从DS18B20读取一个字节 void DS18B20_Read_Temp(void) { u8 Dbit; R_DS18B20_ComuTime++; if(R_DS18B20_ComuTime == 1) { DS18B20_IO_OUT(); //SET PG11 OUTPUT DS18B20_OUT_L(); DelayNOP(20);//4US DS18B20_OUT_H(); DS18B20_IO_IN(); //拉低4us后拉高准备读取数据 } if(R_DS18B20_ComuTime == 2) { if(DS18B20_DQ_IN) Dbit=1; else Dbit=0; if(Dbit) //注意顺序即可，ds18b20先发送低位到总线上 Dbit=1<<R_DS18B20_WBCnt; R_DS18B20_Data |=Dbit; } if(R_DS18B20_ComuTime > 55) { R_DS18B20_WBCnt++; //完成读取1位 R_DS18B20_ComuTime = 0; if(R_DS18B20_WBCnt > 7) { R_DS18B20_WBCnt = 0; if(!R_DS18B20_Bytecnt) { R_DS18B20_Bytecnt++; R_DS18B20_TempL = R_DS18B20_Data;//读取第一个字节 R_DS18B20_Data = 0; } else { R_DS18B20_TempH = R_DS18B20_Data; //读取第二个字节 R_DS18B20_Bytecnt = 0; R_DS18B20_State = ReadOK_STU; R_DS18B20_Data = 0; } } } } void Get_Ds18b20Temp(void) { int temp=0; short tem; if(R_DS18B20_State == DisRequset_STU) R_DS18B20_State = EnableRequest_STU; if(R_DS18B20_State == ReadOK_STU) { R_DS18B20_State = DisRequset_STU; if(R_DS18B20_TempH > 7) //通过判读存储器的高五位的0，1来判断温度的正负， { temp = 0; //为负 R_DS18B20_TempH =~R_DS18B20_TempH; R_DS18B20_TempL =~R_DS18B20_TempL; } else temp = 1; //为正 tem = R_DS18B20_TempH; tem =tem<<8; tem =tem+R_DS18B20_TempL; tem = (double)tem * 0.625; //转换 tem = tem/10; if(temp) R_GotTemp = tem; else R_GotTemp = -tem; } }