⚠️ THIS FEATURE IS AVAILABLE ON CC2652 or CC1352 CHIPS ONLY

The MAX31855 performs cold-junction compensation and digitizes the signal from a K-, J-, N-, T-, S-, R-, or E-type thermocouple. The data is output in a signed 14-bit, SPI-compatible. Because data is read-only, (the sensor does not have any configuration options), the MOSI pin is not required.

This feature should also work with MAX6675 (obsolete).

MAX31855/MAX31865 configuration
MAX31855/MAX31865 configuration
  1. Define the SPI CS pin and select the “MAX31855,MAX31865” from the list.
  2. Select the MISO pin from the list.
  3. Immediately after the CS pin, define the “SPI CLK” pin (Output 2 in the example above).

Note: You can share “MISO”, “MOSI” and “CLK” pin between several sensors.

MAX31865 requires more settings:

  1. Define the MISO pin as you did it for MISO.
  2. Select the thermocouple type (PT100 or PT1000).
  3. Select wiring type (2 or 4 wires).
  4. Select the reference resistor value (usually, 430 Ohm for PT100, and 4300 Ohm for PT1000). It may depend on your schematic. If your sensor board uses other resistor type, the firmware will calculate a temperature incorrectly.

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The firmware sends a temperature in periodic reports as an analog value.


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