STM32 Nucleo and TMP175 digital temperature sensor Arduino example

OK we are now going to look at an TMP175 attached to the STM32 Nucleo and all development will be done on the Arduino IDE – Install STM32 support in the Arduino IDE

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

  • TMP175: 27 Addresses
  • TMP75: 8 Addresses, NIST Traceable
  • Digital Output: SMBus™, Two-Wire™, and I2C
    Interface Compatibility
  • Resolution: 9 to 12 Bits, User-Selectable
  • Accuracy:
    • ±1°C (Typical) from –40°C to 125°C
    • ±2°C (Maximum) from –40°C to 125°C
  • Low Quiescent Current: 50-µA, 0.1-µA Standby
  • Wide Supply Range: 2.7 V to 5.5 V
  • Small 8-Pin MSOP and 8-Pin SOIC Packages

 

Connection

Module Connection STM Nucleo Connection
VCC 3v3
GND Gnd
SDA SDA
SCL SCL

 

Code

#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(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
 
}

 

Output

Open the serial monitor window

The temperature is 23.5625 degrees C
The temperature is 23.5625 degrees C
The temperature is 23.6250 degrees C
The temperature is 24.1875 degrees C
The temperature is 25.3750 degrees C
The temperature is 26.2500 degrees C
The temperature is 26.9375 degrees C
The temperature is 27.4375 degrees C
The temperature is 27.5000 degrees C
The temperature is 27.5000 degrees C
The temperature is 27.4375 degrees C

Link

1pcs CJMCU-175 TMP175 27 Address Digital Temperature Sensor