Thermal Zone

Thermal management is necessary to ensure proper operation of the phyCORE-i.MX7 SOM, especially when integrated inside an enclosure. The phyCORE-i.MX7 has a temperature rating of -40°C to 85°C. This guide will show you how to read the junction temperature of the processor on the phyCORE-i.MX7 SOM.

Reading the Temperature

The phyCORE-i.MX7 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.

• To output the temperature of thermal zone 0 run the following command:

  Target (Linux)

  cat /sys/class/thermal/thermal_zone0/temp
  

  Expetced Output

  root@phyboard-zeta-imx7d-1:~# cat /sys/class/thermal/thermal_zone0/temp
  28000
  

This output translates to 28.0C

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:

  Target (Linux)

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

  Expetced Output

  root@phyboard-zeta-imx7d-1:~# cat /sys/class/thermal/thermal_zone0/trip_point*
  85000
  passive
  90000
  critical
  

The critical trip point which will cause the system to shutdown will be reached when the temperature reaches 105C.