Apalis TK1 temperature sensors

Dear Support Team,

To read Apalis TK1 temperature sensors via linux, I got below different thermal zones temperature:

cat /sys/devices/virtual/thermal/thermal_zone*/temp

note: * is from 0-5, totally six temperatures.

And according to below wiki page - link text, from the “type” definition as below, we can find thermal_zone0-3 is sensors inside the K1 SoC; thermal_zone4 and 5 are sensors on Nvdia Jetson board.

ubuntu@tegra-ubuntu:~$ cat /sys/devices/virtual/thermal/thermal_zone0/type      
ubuntu@tegra-ubuntu:~$ cat /sys/devices/virtual/thermal/thermal_zone1/type      
ubuntu@tegra-ubuntu:~$ cat /sys/devices/virtual/thermal/thermal_zone2/type      
ubuntu@tegra-ubuntu:~$ cat /sys/devices/virtual/thermal/thermal_zone3/type      
ubuntu@tegra-ubuntu:~$ cat /sys/devices/virtual/thermal/thermal_zone4/type      
ubuntu@tegra-ubuntu:~$ cat /sys/devices/virtual/thermal/thermal_zone5/type      

But on Apalis Tk1 datasheet section 9.6 Thermal Specification, only 2 temperature sensors are mentioned as below:

The Apalis TK1 modules come with 2 temperature sensors - one which measures the temperature of the CPU die and another on the Apalis PCB

So could you help specify the Apalis TK1 temperature sensors definition with corresponded above thermal zone definition?

Thanks and Best Regards


TK1 SoC provides internal sensors for:


On Apalis TK1 we’re added TMP451 device that measures it’s own temperature and monitors TK1 SoC temperature (TK1 SoC provides special internal pn junction for external temp. monitoring). This way we can provide additional thermal protection of the TK1 SoC (in extreme case TMP451 will inform the PMIC that we’ve reached overheat condition, and PMIC will cut the power to the TK1 protecting the SoC)

Dear Dominik,

Thanks for the reply, but on Apalis TK1, we can still read temperature for thermal_zone4(Tboard_tegra) and thermal_zone5 (Tboard_tegra), is there any meaning for this?

ubuntu@tegra-ubuntu:~$ cat /sys/devices/virtual/thermal/thermal_zone4/temp      
ubuntu@tegra-ubuntu:~$ cat /sys/devices/virtual/thermal/thermal_zone5/temp      

And to read TMP451 device temperature, is that correct to check the 4-004c device as below? and two numbers are shown under “temperature”, do you know what do they mean separately? Also, there is another file “ext_temperature”, what’s this mean?

ubuntu@tegra-ubuntu:~$ cat /sys/bus/i2c/devices/4-004c/temperature              
32 33.0                                                                         
ubuntu@tegra-ubuntu:~$ cat /sys/bus/i2c/devices/4-004c/ext_temperature          



temperature is TBoard and ext_temperature is Tdiode

Dear Dominik,

Got it, Thanks a lot!

And i also find below information just now on Nvidia developer website for all the readers reference.

CPU-therm: Tsensor inside TK1, close to CPU part.
GPU-therm: Tsensor inside TK1, close to GPU part.
MEM-therm: Tsensor inside TK1, close to MEM part.
PLL-therm: Tsensor inside TK1, close to PLL part.
Tboard_tegra: Tsensor inside external temperature sensor, take the local temperature as PCB temperature. 
Tdiode_tegra: External temperature sensor read the temperature through Tdoide inside TK1, Tdiode is close to CPU and GPU part. it's more accurate than TK1 internal Tsensor readout.