Reading SOC temperature on AM62xx

Hello Gokul,

Thank you for the query.

Gokul Kujulva said:

We need support on reading SOC temperature for Sitara Platform AM62xx.

I assume your query is regarding the VTM internal temperature sensor.

Have you had a chance to look at the below documentation?

https://software-dl.ti.com/processor-sdk-linux/esd/AM62X/08_06_00_42/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/VTM.html?highlight=vtm

Regards,

Sreenivasa

Sreeni, thanks for the update,

Is it validated on Am62x-EVM ?

Thanks  & regards,

Gokul

Hello Gokul,

Thank you for the note.

Gokul Kujulva said:

Is it validated on Am62x-EVM ?

I would believe so. Please let mw know if you have any questions so that i can check.

Regards,

Sreenivasa

Hello Gokul, Vadivel,

Bringing the conversation from email thread to E2E:

In order to measure the SOC temperature from M4 core, you can follow the steps mentioned below:

1. DATA_OUT[0-9] bitfields stated in TRM section "6.2.5.5.2.1.1 10-bit Temperature Values Versus Temperature" correspond with physical address "00B0 0308h"
2. From M4 core, you can check the value at the register 0x80B00308. Because of RAT configuration, the address 0xB00308 gets mapped to 0x80B00308 in M4 default SDK.
3. Convert the value read at the register to binary format and take the 10 least significant bits Calculate the decimal value of the number obtained.
4. You can substitute the number calculated in step 2 and substitute it in the equation mentioned in the TRM and calculate the SOC temperature.

(Adding an example below for better understanding)

Example

1.

2. 8095F = 00000000000010000000100101100001 -> 0101100001 = 353 (Taking 10 least significant bits)

3. a.

         a. Substitute x=353 in the equation above and calc. the SOC temperature.

         b.(-9.2627E-12)x(353)⁴ +(6.0373E-08)x(353)³ +(-1.7058E-04)x(353)² +(3.2512E-01)x(353) +(-4.9002E+01) = 47.02384904775517°C

Yes, the AM62 SOC temperature can be obtained from Linux (in milliCelcius) with the below command:
cat /sys/class/thermal/thermal_zone*/temp

Regards,
Krithika