Thermal Zone

This guide will show you how to read the junction temperature of the processor on the phyCORE-i.MX7 SOM.

Step-by-Step Guide

Reading the Temperature

The phyCORE-i.MX7 processor has 1 physical location where the temperature can be monitored (thermal zone). The available zone can be accessed in the Linux directory /sys/class/thermal/thermal_zone0

The below command can be used to output the temperature of thermal zone 0.

cat /sys/class/thermal/thermal_zone0/temp

root@imx7d-phyboard-zeta-004:~# cat /sys/class/thermal/thermal_zone0/temp
54000

This output translates to 54.0C

Temperature Trip Points

The thermal zone includes trip points. You can set the trip points to a temperature that will trigger an event, such as turning on a fan for active cooling. You can also build in a critical trip point; if this temperature is reached, Linux will automatically shutdown the system for protection of the processor. 

To view the type of trip points and the trip point temperatures of thermal zone 0 use the following command: 

cat /sys/class/thermal/thermal_zone0/trip_point*

root@imx7d-phyboard-zeta-004:~# cat /sys/class/thermal/thermal_zone0/trip_point*
85000
passive
90000
critical