max6675

This project is a solution verification version for [Lichuang Mall](https://www.szlcsc.com/)MAX6675ISA ([Product No.: C16030](https://item.szlcsc.com/16712.html)) design.

This project is a sample project of [EDA Open Source Hardware Platform](https://oshwhub.com/) [Solicitation Order for Solution Verification Module](https://oshwhub.com/rewards/f4bbab6365034e80aadb8f8ebf77c846).

MAX6675 is a K-type thermocouple converter with cold-junction compensation, 12-bit output resolution, and is compatible with a simple SPI interface.
Temperature measurement range 0℃-1024℃.
The K-type thermocouple inputs are from T+ and T- of the MAX6675. The MAX6675 contains signal conditioning hardware that is used to convert the thermocouple signal to the appropriate voltage. Internal circuitry connected to T+ and T- is used to weaken the signal from the thermocouple wire. introduced noise.
Before converting the thermocouple voltage to an equivalent temperature, the difference between the thermocouple cold junction and the virtual 0°C must be compensated.
The voltage change rate of K-type thermocouple is 41uV/℃.
Vout=(41uV/℃.)x(**T**R-TAMB)
Vout: Thermocouple output voltage (uV)
TR: Thermocouple remote temperature
TAMB: Ambient temperature

In this verification board, MAX6675 reads the thermocouple input and the converted value is sent out through the serial interface. The microprocessor pulls CS low and outputs the clock signal to the SCK pin. The result can be read on the SO pin. When CS becomes low level, Terminate any conversion result. CS jumps to high level to start a new conversion process. Once CS jumps to low level, the SO pin outputs the first bit. A complete serial interface reading process requires 16 clock cycle, read 16 output bits at the falling edge of the clock cycle. The first bit D15 is a false new number and is read as 0. Bits D14-D3 correspond to converting the MSB of the temperature value to LSB. Bit D2 is generally 0. When the thermocouple is open circuit, it jumps to 1, D1 is 0, which is used to provide the ID of the device, and D0 is three-state.