ds18b20 代码

以下是 DS18B20 温度传感器的 Arduino 代码示例：

#include <OneWire.h>

// DS18B20 数据线连接到 Arduino 引脚 2
#define ONE_WIRE_BUS 2

OneWire oneWire(ONE_WIRE_BUS);

void setup() {
  Serial.begin(9600);
}

void loop() {
  byte i;
  byte present = 0;
  byte type_s;
  byte data[12];
  byte addr[8];

  if ( !oneWire.search(addr)) {
    Serial.println("No more addresses.");
    oneWire.reset_search();
    delay(250);
    return;
  }

  Serial.print("ROM =");
  for( i = 0; i < 8; i++) {
    Serial.write(' ');
    Serial.print(addr[i], HEX);
  }

  if (OneWire::crc8(addr, 7) != addr[7]) {
      Serial.println("CRC is not valid!");
      return;
  }
  Serial.println();

  // 温度传感器类型判断
  switch (addr[0]) {
    case 0x10:
      Serial.println("  Chip = DS18S20");  // or old DS1820
      type_s = 1;
      break;
    case 0x28:
      Serial.println("  Chip = DS18B20");
      type_s = 0;
      break;
    case 0x22:
      Serial.println("  Chip = DS1822");
      type_s = 0;
      break;
    default:
      Serial.println("Device is not a DS18x20 family device.");
      return;
  }

  // 温度读取
  oneWire.reset();
  oneWire.select(addr);
  oneWire.write(0x44,1);         // 开始温度转换，参数为 1 表示使用最高分辨率
  delay(1000);                   // 等待转换完成
  present = oneWire.reset();
  oneWire.select(addr);    
  oneWire.write(0xBE);           // 发送读取命令
  for ( i = 0; i < 9; i++) {     // 读取 9 字节数据
    data[i] = oneWire.read();
  }
  int16_t raw = (data[1] << 8) | data[0];
  if (type_s) {
    raw = raw << 3; // 9 bit resolution default
    if (data[7] == 0x10) {
      // "count remain" gives full 12 bit resolution
      raw = (raw & 0xFFF0) + 12 - data[6];
    }
  } else {
    byte cfg = (data[4] & 0x60);
    if (cfg == 0x00) raw = raw & ~7;  // 9 bit resolution, 93.75 ms
    else if (cfg == 0x20) raw = raw & ~3; // 10 bit res, 187.5 ms
    else if (cfg == 0x40) raw = raw & ~1; // 11 bit res, 375 ms
    //// default is 12 bit resolution, 750 ms conversion time
  }
  float celsius = (float)raw / 16.0;
  Serial.print("  Temperature = ");
  Serial.print(celsius);
  Serial.println(" Celsius, ");
}