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AM623: Operating temperature range at DDR config

Libor Krejca
Prodigy 180 points
Part Number: AM623
Other Parts Discussed in Thread: SYSCONFIG

Dear TI support,

I have question to DDR config for Sitara (AM62). I’d like to know what “Operating Temperature Range” does. I believe it should set dual refresh but if I set -40C to +95C then tREFI remains the same (same value is visible in the sysconfig). But we know this setting changes several registers, so is a DRAM timing changed and if yes then which one? Does the temperature range config change tREFI register setting (7800 -> 3900 ns)?

Thanks!

Best regards

Libor

  • 0
    TI__Guru**** 192199 points

    Hello Libor,

    Thank you for the query.

    Libor Krejca said:

    I have question to DDR config for Sitara (AM62). I’d like to know what “Operating Temperature Range” does. I believe it should set dual refresh but if I set -40C to +95C then tREFI remains the same (same value is visible in the sysconfig). But we know this setting changes several registers, so is a DRAM timing changed and if yes then which one? Does the temperature range config change tREFI register setting (7800 -> 3900 ns)?

    Please refer below E2E

    https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1234907/am625-lpddr4-configuration-and-operating-temperature?tisearch=e2e-sitesearch&keymatch=Operating%2520Temperature%2520Range#

    I  need to check on the support.

    There is a readme file that you could refer as part of the sysconfig file.. I would suggest reading the same.

    Let me check internally and update.

    Regards,

    Sreenivasa

  • 0 in reply to Kallikuppa Sreenivasa
    Prodigy 180 points

    Hello Sreenivasa,

    the readme file for DDR config tool v9.09 says:

    " if changing Operating Temperature Range, the derating required for high temperatures will automatically be added to the appropriate parameters. However, **you must adjust tREFIab and tREFIpb manually in DRAM Timing B) section according to your memory device datasheet. You must also adjust tRASmax, as this parameter is dependent on the refresh rate** "

    I use DDR4 for AM62x and DDR4 config includes just tREFI and tRAS, so I think the manual adjustment is necessary just for some of the LPDDR4 parameters, is it correct? If I set operating temperature -40 to +95C at DDR4 config then the config tool automatically sets tREFI 3900ns in the generated files, right?

    BTW, do you know when TI plans to support the dynamic changes (Temperature-Controlled Refresh Mode)?

    Thanks!

    Best regards

    Libor

  • 0 in reply to Libor Krejca
    Intellectual 326 points

    Hello TI,

    I post here because questions seem related to mine.

    Rewording his question: "added auto adjustments of tRAS and tREFI with change in temp selection" in readme is effectively the runtime support for LPDDR4 temperature (with auto adjustment of refresh rate)? What is the relevant SDK version supporting this (I suppose we need both new configuration and new software)?

    This is linked to mine previous question here: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1234907/am625-lpddr4-configuration-and-operating-temperature

    Thank you

    Emanuele

  • 0 in reply to Kallikuppa Sreenivasa
    Prodigy 180 points

    Hello Sreenivasa,

    do you have any news to my questions from last comment? I wrote:

    "I use DDR4 for AM62x and DDR4 config includes just tREFI and tRAS, so I think the manual adjustment is necessary just for some of the LPDDR4 parameters, is it correct? If I set operating temperature -40 to +95C at DDR4 config then the config tool automatically sets tREFI 3900ns in the generated files, right? Do you know if and when TI plans to support the dynamic changes (Temperature-Controlled Refresh Mode)?"

    Thanks!

    Best regards

    Libor

  • 0 in reply to Emanuele Ghidoli
    TI__Guru**** 192199 points

    Hi All, 

    Thank you for the follow0up queries.

    I have these queries assigned to the DDR expert to provide his inputs.

    Regards,

    Sreenivasa

  • +1 in reply to Kallikuppa Sreenivasa
    TI__Guru* 86820 points

    Hi Libor and Emanuele,

    we are in a bit of a transitional period to help support the range of temps supported by DDR. 

    First for LPDDR4, i believe the v9.1 of the SDK (not released yet) will support dynamic changes (ie, temperature controlled refresh mode).  Currently, you have to choose the highest temperature you plan to operate, and configure the DDR Register Configuration Tool for that temperature.  The latest version of the tool v9.09 will automatically change the appropriate parameters when the temp setting is changed in the tool.  You will see these values change in the tool as you change the temp setting.   Since dynamic refresh rate changes aren't support yet, the tool will simply configure the refresh rate to 4x to support the higher temps.  It will also derate some of the other timings automatically, so all you should need to do is set the temp in the tool appropriately (there appears to be some typos in the README related to this, which will get fixed in the next release)

    For DDR4, it is a different story.  DDR4 doesn't have the same temp refresh mode as LPDDR4, so this is not relevant for software to support.  In the tool, you would choose the appropriate temp range for your design, and this will change MR2[7:6]= 11b to support auto self refresh mode.  MR4[3:2]  will also be changed to 11b to support temperature controlled refresh.  tREFI, tRFC, and tRAS do not automatically change, so this will need to be done by the user.  A future version of the tool will auto change the refresh rate to facilitate this.

    Hope this clears it up

    Regards,

    James

  • 0 in reply to JJD
    Intellectual 326 points

    Hi James,

    thank you for the detailed answer.

    Kind regards,

    Emanuele

  • 0 in reply to Emanuele Ghidoli
    TI__Guru**** 192199 points

    Hello Emanuele,

    Thank you for the note.

    I am closing the thread.

    Regards,

    Sreenivasa