USB interface for ADT7422 temperature sensor based on STM32F4 board by WeAct.

• PB6 - I2C Data
• PB7 - I2C Clock

The board send temperature readings over Virtual COM-port every second. The data is being send in the following format:

Where CRC8 is calculated by:

uint8_t CRC8(const uint8_t *data, size_t length) {
    uint8_t crc = 0;
    
    for (size_t i = 0; i < length; ++i) {
        crc ^= data[i];
        
        for (int j = 0; j < 8; ++j) {
            if (crc & 0x80) {
                crc = (crc << 1) ^ 0x07;  // Polynomial 0x07
            } else {
                crc <<= 1;
            }
        }
    }
    
    return crc;
}

Use the following formulas to calculate the measured temperatures in °C from the ADT7422 output codes in 16-bit format (where ADC Code uses all 16 bits of the data byte, including the sign bit):

Positive Temperature = ADC Code (Decimal)/128
Negative Temperature = (ADC Code (Decimal) − 65,536)/128

Where Bit 15 (sign bit) is removed from the ADC code:

Negative Temperature = (ADC Code (Decimal) − 32,768)/128

Project can be built in Visual Studio Code with C/C++ and STM32 plugins installed.

To build and debug ARM Embedded Toolchain and OpenOCD are both required.