Microbit and TMP175 digital temperature sensor example

The TMP75 and TMP175 devices are digital temperature sensors ideal for NTC and PTC thermistor replacement. The devices offer a typical accuracy of ±1°C without requiring calibration or external component signal conditioning. IC temperature sensors are highly linear and do not require complex calculations or look-up tables to derive the temperature. The on-chip 12-bit ADC offers resolutions down to 0.0625°C. The devices are available in the industry standard LM75 SOIC-8 and MSOP-8 footprint.

The TMP175 and TMP75 feature SMBus, Two-Wire, and I²C interface compatibility. The TMP175 device allows up to 27 devices on one bus. The TMP75 allows up to eight 8 on one bus. The TMP175 and TMP75 both feature an SMBus Alert function.

The TMP175 and TMP75 devices are ideal for extended temperature measurement in a variety of communication, computer, consumer, environmental, industrial, and instrumentation applications.

Features

Connection

Code

[codesyntax lang=”cpp”]

#include <Wire.h> 

byte TempHi;              // Variable hold data high byte
byte TempLo;              // Variable hold data low byte
boolean P_N;              // Bit flag for Positive and Negative
unsigned int Decimal;     // Variable hold decimal value

void Cal_Temp();
/*******************************************************************************
                      Setup
*******************************************************************************/ 
void setup() 
{ 
  Serial.begin(9600);
  Wire.begin();             // join i2c bus (address optional for master) 
  delay(1000);
} 
 
/*******************************************************************************
                      Main Loop
*******************************************************************************/  
void loop() 
{
  const int I2C_address = 0x37;  // I2C write address 
    
  delay(100);
  Wire.beginTransmission(I2C_address);
  Wire.write(1);             // Setup configuration register
  Wire.write(0x60);          // 12-bit
  Wire.endTransmission(); 
  
  Wire.beginTransmission(I2C_address);
  Wire.write((byte)0);             // Setup Pointer Register to 0
  Wire.endTransmission(); 
  
  while (1)
  {
    delay(1000);
    
    // Read temperature value
    Wire.requestFrom(I2C_address, 2);
    while(Wire.available())          // Checkf for data from slave
    {                                
      TempHi = Wire.read();       // Read temperature high byte
      TempLo = Wire.read();       // Read temperature low byte
    } 
    Cal_Temp ();
    
    // Display temperature
    Serial.print("The temperature is ");
    if (P_N == 0)
      Serial.print("-");
    Serial.print(TempHi,DEC);
    Serial.print(".");
    Serial.print(Decimal,DEC);
    Serial.println(" degree C");
  }  
}

void Cal_Temp()
{
  if (TempHi&0x80)          // If bit7 of the TempHi is HIGH then the temperature is negative
    P_N = 0;
  else                      // Else the temperature is positive
    P_N = 1;
  
  TempHi = TempHi & 0x7F;   // Remove sign
  TempLo = TempLo & 0xF0;   // Filter out last nibble
  TempLo = TempLo >>4;      // Shift right 4 times
  Decimal = TempLo;
  Decimal = Decimal * 625;  // Each bit = 0.0625 degree C
    
}

[/codesyntax]

Output

Open the serial monitor and you will see something like this

The temperature is 23.5000 degree C
The temperature is 23.5625 degree C
The temperature is 25.3125 degree C
The temperature is 26.7500 degree C
The temperature is 27.8125 degree C
The temperature is 28.5000 degree C
The temperature is 28.9375 degree C
The temperature is 29.3750 degree C
The temperature is 29.6875 degree C
The temperature is 29.9375 degree C
The temperature is 30.1250 degree C
The temperature is 30.3125 degree C

Link

1pcs CJMCU-175 TMP175 27 Address Digital Temperature Sensor