番禺做网站技术,超酷网站模板,自己做网站怎么赚钱,长春关键词排名优化简介 我们知道多个DS18B20的DQ线是可以被挂在一起的, 也就是一根线上可以访问不同的DS18B20而不会造成数据错乱, 怎么做到的#xff0c;其实数据手册都有说到#xff0c; 就是靠64-bit ROM code 进行识别, 也可以理解成Serial Number进行识别, 因为主要差异还是在Serial Numb…简介 我们知道多个DS18B20的DQ线是可以被挂在一起的, 也就是一根线上可以访问不同的DS18B20而不会造成数据错乱, 怎么做到的其实数据手册都有说到 就是靠64-bit ROM code 进行识别, 也可以理解成Serial Number进行识别, 因为主要差异还是在Serial Number上面; 电路图 两个DS18B20连接到一起 实现步骤 创建项目 基于 上一篇 普中STM32-PZ6806L开发板(HAL库函数实现-温度传感器DS18B20) 添加用户代码 获取DS18B20的Serial Number信息, 然后记录下来, 用于向指定DS18B20获取温度值 typedef struct {uint8_t familyCode;uint8_t sns[6];uint8_t crc; } SENSOR_DS18B20_SerialNumberInfo;SENSOR_DS18B20_SerialNumberInfo SENSOR_DS18B20_GetSN(void) {SENSOR_DS18B20_SerialNumberInfo info;uint8_t recvs[8] { 0 };SENSOR_DS18B20_Reset ();HAL_Delay (1);SENSOR_DS18B20_Write (0x33); // read romHAL_Delay (1);// 1 byte - family code// 2 ~ 7 byte - serial number// 8 byte - CRC8 recvs[0] SENSOR_DS18B20_Read(); // family codeinfo.familyCode recvs[0];for (int i 0; i 6; i) // serial number{ recvs[i1] SENSOR_DS18B20_Read();info.sns[i] recvs[i1];}recvs[7] SENSOR_DS18B20_Read(); // CRC8info.crc recvs[7];if (SENSOR_DS18B20_CRC8(recvs, 7) ! recvs[7]) // CRC8 检查{info.familyCode 0;memset(info.sns, 0, sizeof(info.sns)/sizeof(uint8_t));info.crc 0; return info; // CRC校验不一致}return info; }实现流程参考pdf 实现代码 /* 两个DS18B20设备 */ #include stdio.h #include string.h/* DS18B20, 提前读取出来的SNfamilyCodeCRC码 */ SENSOR_DS18B20_SerialNumberInfo ds18b20_infos[] {{ 0x28, { 0x2E, 0x7C, 0x04, 0x05, 0x00, 0x00 }, 0xCC },{ 0x28, { 0x2F, 0x7D, 0x10, 0x02, 0x01, 0x00 }, 0xBE } };/* 引脚重新设置为输入 */ static void SENSOR_DS18B20_SetPinInput(GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin) {GPIO_InitTypeDef GPIO_InitStruct;GPIO_InitStruct.Pin GPIO_Pin;GPIO_InitStruct.Mode GPIO_MODE_INPUT;GPIO_InitStruct.Pull GPIO_NOPULL;HAL_GPIO_Init(GPIOx, GPIO_InitStruct); } /* 引脚重新设置为输出 */ static void SENSOR_DS18B20_SetPinOutput(GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin) {GPIO_InitTypeDef GPIO_InitStruct;GPIO_InitStruct.Pin GPIO_Pin;GPIO_InitStruct.Speed GPIO_SPEED_FREQ_HIGH;GPIO_InitStruct.Mode GPIO_MODE_OUTPUT_PP;HAL_GPIO_Init(GPIOx, GPIO_InitStruct); }/*SENSOR_DS18B20_Reset :初始化也是复位, 每次发送指令前的动作0 : 初始化失败1 : 初始化成功 */ static uint8_t SENSOR_DS18B20_Reset(void) {uint8_t res 0;SENSOR_DS18B20_SetPinOutput(DS18B20_PORT, DS18B20_PIN); // 引脚输出模式HAL_GPIO_WritePin (DS18B20_PORT, DS18B20_PIN, 0); // 拉低引脚delay_us (480); // 参考初始化时序图, 延时480usSENSOR_DS18B20_SetPinInput(DS18B20_PORT, DS18B20_PIN); // set the pin as inputdelay_us (60); // 15~60us等待DS18B20回复信息, 多等20us避免检测不到if ( !HAL_GPIO_ReadPin(DS18B20_PORT, DS18B20_PIN) )res 1; // 检测到低电平, DS18B20有响应else res 0;delay_us (420); // 等待DS18B20结束响应return res; }/* 写流程 */ void SENSOR_DS18B20_Write(uint8_t data) {/*按位写, 根据时序图, 按照写的 高电平的时序 和 低电平的时序进行延时*/for (int i 0; i 8; i){if ((data (1i))!0) // 写1{SENSOR_DS18B20_SetPinOutput(DS18B20_PORT, DS18B20_PIN); HAL_GPIO_WritePin(DS18B20_PORT, DS18B20_PIN, 0); // 拉低delay_us (2); // 低电平保持时间SENSOR_DS18B20_SetPinInput(DS18B20_PORT, DS18B20_PIN); // 输入delay_us (60); // 等待}else // 写0{SENSOR_DS18B20_SetPinOutput(DS18B20_PORT, DS18B20_PIN);HAL_GPIO_WritePin (DS18B20_PORT, DS18B20_PIN, 0); // 拉低delay_us (60); // 等待60usSENSOR_DS18B20_SetPinInput(DS18B20_PORT, DS18B20_PIN); // 输入}} } /* 读流程 */ uint8_t SENSOR_DS18B20_Read (void) {uint8_t value 0;SENSOR_DS18B20_SetPinOutput(DS18B20_PORT, DS18B20_PIN);for (int i0;i8;i){SENSOR_DS18B20_SetPinOutput(DS18B20_PORT, DS18B20_PIN);HAL_GPIO_WritePin(DS18B20_PORT, DS18B20_PIN, 0); // 拉低delay_us(2); // 拉低电平等待时间SENSOR_DS18B20_SetPinInput(DS18B20_PORT, DS18B20_PIN);if (HAL_GPIO_ReadPin (DS18B20_PORT, DS18B20_PIN)) {value | 1i; }delay_us (60); // DS18B20数据响应时间}return value; }/* 计算CRC码 */ uint8_t SENSOR_DS18B20_CRC8(uint8_t *dats, uint8_t len) {uint8_t i, dat, crc, fb, st_byt;st_byt 0;crc 0;do {dat dats[st_byt];for (i 0; i 8; i) { fb crc ^ dat;fb 1;crc 1;dat 1;if (fb 1) crc ^ 0x8c; }st_byt;} while (st_byt len); return crc; }/* 获取Serial NumberCRCfamily Code */ SENSOR_DS18B20_SerialNumberInfo SENSOR_DS18B20_GetSN(void) {SENSOR_DS18B20_SerialNumberInfo info;uint8_t recvs[8] { 0 };SENSOR_DS18B20_Reset ();HAL_Delay (1);SENSOR_DS18B20_Write (0x33); // read romHAL_Delay (1);// 1 byte - family code// 2 ~ 7 byte - serial number// 8 byte - CRC8 recvs[0] SENSOR_DS18B20_Read(); // family codeinfo.familyCode recvs[0];for (int i 0; i 6; i) // serial number{ recvs[i1] SENSOR_DS18B20_Read();info.sns[i] recvs[i1];}recvs[7] SENSOR_DS18B20_Read(); // CRC8info.crc recvs[7];if (SENSOR_DS18B20_CRC8(recvs, 7) ! recvs[7]) // CRC8 检查{info.familyCode 0;memset(info.sns, 0, sizeof(info.sns)/sizeof(uint8_t));info.crc 0; return info; // CRC校验不一致}return info; }/* 写Serial NumberCRCfamily Code */ void SENSOR_DS18B20_WriteID(uint8_t index) {uint8_t id_data[8];id_data[0] ds18b20_infos[index].familyCode;id_data[7] ds18b20_infos[index].crc;for ( int i 1; i 7; i ){id_data[i] ds18b20_infos[index].sns[i-1];}SENSOR_DS18B20_Reset (); SENSOR_DS18B20_Write (0x55); // skip ROM; //Match ROM [55h]for ( int i 0; i 8; i ){SENSOR_DS18B20_Write(id_data[i]);} }/* 等待电平被拉高 */ void SENSOR_DS18B20_WaitForHigh(uint32_t time) {SENSOR_DS18B20_SetPinInput(DS18B20_PORT, DS18B20_PIN);delay_us(time);while(HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_9) 0);SENSOR_DS18B20_SetPinOutput(DS18B20_PORT, DS18B20_PIN); }/* 将读取值转化成温度值 */ float SENSOR_DS18B20_ValueToTemperature(uint8_t lsb, uint8_t msb) {uint16_t temp 0;temp (msb 8) lsb;if((temp0xf800)0xf800) // 符号位判定是否负数{temp(~temp)1; // 补码转原码return temp*(-0.0625); //12bit 增量值}else{return temp*0.0625; //12bit 增量值} }/* 通过serial number数据获取温度 */ float SENSOR_DS18B20_GetTemperatureByID(uint8_t ds18b20_index) {uint8_t recv_data[] { 0, 0, 0, 0, 0, 0, 0, 0, 0 }; // 9 Bytesuint8_t ds18b20_num sizeof(ds18b20_infos) / sizeof(SENSOR_DS18B20_SerialNumberInfo);uint16_t temp 0;if ( ds18b20_index ds18b20_num )return 0; // 不存在此设备SENSOR_DS18B20_Reset ();HAL_Delay (1);SENSOR_DS18B20_WriteID(ds18b20_index);SENSOR_DS18B20_Write(0x44);//Convert Temperature [44h]SENSOR_DS18B20_WaitForHigh(20);SENSOR_DS18B20_Reset ();SENSOR_DS18B20_WriteID(ds18b20_index);SENSOR_DS18B20_Write(0xBE);//Read Scratchpad [BEh]for (uint8_t i 0; i 9; i){recv_data[i] SENSOR_DS18B20_Read();}return SENSOR_DS18B20_ValueToTemperature(recv_data[0], recv_data[1]); }代码 无需下载, 代码上面基本都提供了 Note: 支持你的DS18B20, 你需要修改 改成你的DS18B20的信息 SENSOR_DS18B20_SerialNumberInfo ds18b20_infos[] { { 0x28, { 0x2E, 0x7C, 0x04, 0x05, 0x00, 0x00 }, 0xCC }, { 0x28, { 0x2F, 0x7D, 0x10, 0x02, 0x01, 0x00 }, 0xBE } };