普中STM32-PZ6806L开发板(HAL库函数实现-访问多个温度传感器DS18B20)

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
在这里插入图片描述

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[i+1] = SENSOR_DS18B20_Read();info.sns[i] = recvs[i+1];}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
在这里插入图片描述
实现代码

/* 两个DS18B20设备 */
#include <stdio.h>
#include <string.h>/* DS18B20, 提前读取出来的SN&familyCode&CRC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 & (1<<i))!=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 i=0;i<8;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 |= 1<<i;  }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 Number&CRC&family 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[i+1] = SENSOR_DS18B20_Read();info.sns[i] = recvs[i+1];}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 Number&CRC&family 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((temp&0xf800)==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 }
};

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