MAX6675

Arduino library for interfacing with MAX6675 thermocouple amplifier. Originally from Adafruit but as they abandoned the repository, @SirUli forked and updated the repository from all current pull requests on the repository.

Usage

Initialization

Wiring

There are different namings for each of the connections out there. Therefore copied from Wikipedia:

Name in the library	Long Name	Other names
SCLK	Serial Clock	SCK, CLK
CS	Slave Select	nCS, SS, CSB, CSN, EN, nSS, STE, SYNC, SSQ
MISO	Master Input / Slave Output	SOMI, SDO (for slave devices ), DO, DOUT, SO, MRSR

Ensure to wire this correctly.

Regular setup

Important due to a specific behaviour in platformio, the SPI library needs to be included in the main file:

#include <SPI.h>

See here for the explanation.

Setup the Sensor like this:

MAX6675 thermocouple;

During the setup method, you need to choose whether you initialize the Hardware SPI outside the MAX sensor or if the library should take care of it all.

Library takes care

Set the pins for SCLK, CS, MISO as arguments. You can additional set the optional offset for the temperature in degrees Celsius. If you want to use Fahrenheit offsets, you need to set that using setOffsetFahrenheit();

thermocouple.begin(SCLK, CS, MISO[, OFFSET]);

Hardware SPI

@eadf added a hardware SPI mode. In this mode the SPI pins can be reused for your MAX6675 device as well as any other SPI gadget you got connected. Assumes you already have setup SPI with SPI.begin(). You can additional set the optional offset for the temperature in degrees Celsius. If you want to use Fahrenheit offsets, you need to set that using setOffsetFahrenheit();

thermocouple.begin(CS[, OFFSET]);

Legacy initialization in constructor

SPI Setup

If the SPI is not used for anything else, then setup the Sensor like this. You can additional set the optional offset for the temperature in degrees Celsius. If you want to use Fahrenheit offsets, you need to set that using setOffsetFahrenheit();

MAX6675 thermocouple(SCLK, CS, MISO[, OFFSET]);

Hardware SPI

@eadf added a hardware SPI mode. In this mode the SPI pins can be reused for your MAX6675 device as well as any other SPI gadget you got connected. Assumes you already have setup SPI with SPI.begin(). You can additional set the optional offset for the temperature in degrees Celsius. If you want to use Fahrenheit offsets, you need to set that using setOffsetFahrenheit(); Use the single value constructor to access this mode:

MAX6675 thermocouple(CS[, OFFSET]);

Methods

Retrieves the temperature in degrees Celsius

double readCelsius();

Retrieves the temperature in degrees Fahrenheit

double readFahrenheit();

Configures an offset in degrees Celsius for the sensor

void setOffsetCelsius();

Configures an offset in degrees Fahrenheit for the sensor

void setOffsetFahrenheit();

Continuous Integration

Release History

• 1.0 Original Release by Adafruit
• 2.0 Move to SirUli's repository with fixes and change of constructor