Create a False Temperature Input

I have a project that uses a k type Thermocouple with a Grove - 1-Wire Thermocouple Amplifier(MAX31850K)
I need to replace the K type thermocouple with another Arduino to simulate temperature
Can someone give me an idea of what voltage/resistance i need to feed the Grove - 1-Wire Thermocouple to get it to read around 800 degrees C