Thermal Zone

This guide will show you how to read the junction temperature of the processor on the phyCORE-i.MX8X SOM.

../_images/pcm-065_thermal.png

Reading Temperature

The phyCORE-i.MX8X processor has 1 physical location (thermal zone) where the temperature can be monitored. The available zone can be accessed in the Linux directory /sys/class/thermal/thermal_zone0.

  • Output the temperature of thermal zone 0

    Target (Linux)
    cat /sys/class/thermal/thermal_zone0/temp
    Expected Output
    38900

    This output translates to 38.9C

Temperature Trip Point

  • View the type of trip points and the trip point temperatures of thermal zone 0.

    Target (Linux)
    cat /sys/class/thermal/thermal_zone0/trip_point*
    Expected Output
    2000
107000
passive
2000
127000
critical

The passive trip point will be reached when the temperature gets below 2C or above 107C. The critical trip point will be reached when the temperature gets below 2C or above 127C

Note

You can set the trip points to a temperature that will trigger an event, such as turning on a fan for active cooling.

In addition you can also build in a critical trip point which will automatically shutdown the system to protect the processor from overheating.