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[DM8148] Monitoring DM8148 temperature

Dylan Alvaro
Intellectual 450 points

Hello TI experts,


I am just wondering if there is a way to monitor the DaVinci temperature ? I am using a custom board with a DM8148 and I would like to perform some tests and see if there is any change in the temperature.

On Linux I know there are some tools (lm-sensors) to measure CPU temperature but I don't even know if there is a temperature sensor inside de DaVinci and I can't find any documentation on this. So if any TI employee could tell me whether there is a way to monitor this temperature or not, this would be great.


Thank you very much for your help

Dylan

  • 0
    TI__Guru**** 170625 points

    Dylan,

    Please refer to the below e2e threads:

    http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/234434.aspx

    http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/717/t/181624.aspx

    Regards,
    Pavel

  • 0 in reply to Pavel Botev
    Intellectual 450 points

    Hi Pavel,


    I looked at these threads and what I understand is that for DM8148 there are no temperature sensors internally therefore I had to manually add one or to find a way to measure the temperature of it, am I right ?

    This is pretty strange that no temperature monitoring is available on such processors. Do you any experience in DM8148 temperature monitoring ?


    Thanks for your answer

    Dylan

  • 0 in reply to Dylan Alvaro
    Mastermind 8040 points

    Dylan Alvaro said:
    This is pretty strange that no temperature monitoring is available on such processors. Do you any experience in DM8148 temperature monitoring ?

    What those links show (note that am387x is basically the same processor as dm814x) is that they are in fact there as part of SmartReflex. However, SmartReflex has been defeatured in the dm814x without explanation:

    • "It is being characterized & not completed yet." (december 2011)
    • "Unfortunately, We do not support SmartReflex yet. Once we do, we will put in our SDK release." (may 2012)
    • "Sorry but the SmartReflex is not going to support on DM8148." (februari 2013)

    I don't know whether the temperature sensor(s) can still be used nonetheless.  I've tried to use it myself and I do get some sort of value (DTEMP=0x7F) when I clear bit 5 and set bit 3, but when I start a conversion the DTEMP becomes zero and ECOZ ("when low, DTEMP is valid") goes high.  Curiously, I did get a different initial value (0x7B) of DTEMP in an earlier test.  Maybe I'm using it wrong or something needs to be enabled elsewhere, there isn't much info to work with.

  • 0 in reply to Matthijs van Duin
    Intellectual 450 points

    Thank you Matthijs for your answer. I'll try to take a look at this DTEMP more deeply to see if I can find something. If I get some results, I'll update this thread.

    Is there any TI expert that can provide documentation about the use of the temperature sensor ? I don't know if there is any but I'd rather ask.

    Thank you

    Dylan

  • 0 in reply to Dylan Alvaro
    Intellectual 450 points

    As I can see on the TRM of the DM8148, BANDGAP0 register has been removed and it is no more described in the TRM. Therefore, I am wondering if this register (BANDGAP0) is still accessible but unused, can someone confirm this ?

    Thanks,

    Dylan

  • 0 in reply to Dylan Alvaro
    TI__Guru**** 170625 points

    Dylan,

    This feature actually exist, but has never been characterized, so an external solution is recommended.

    Here are some links which might be in help:

    http://processors.wiki.ti.com/index.php/AM335x_Thermal_Considerations

    http://processors.wiki.ti.com/index.php/DM814x_AM387x_Power_Estimation

    http://www.eejournal.com/archives/articles/20120802-logicpd/

    Regards,
    Pavel

  • 0 in reply to Pavel Botev
    TI__Guru**** 170625 points

    The things explained in the below DM816x e2e thread are similar for the DM814x device:

    http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/717/p/345137/1207613.aspx#1207613

    Regards,
    Pavel

  • 0 in reply to Pavel Botev
    Intellectual 450 points

    Thanks Pavel, this answered my question !