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AM69: How to use the DDR Subsystem Register Configuration in SysConfig Tool

Daisuke Maeda
Guru 20175 points
Part Number: AM69
Other Parts Discussed in Thread: SYSCONFIG,

Tool/software:

Our customer wants to know how to configure "VREF Control" in "IOControl B) DRAM IO Configuration".

The "DQ or CA VREF" parameter in the config tool can be selected from several values between 10 and 30.

The documentation for J7 below describes that the parameter corresponds to MR14[5:0] and MR12[5:0].

Jacinto7 DDRSS Register Configuration Tool (Rev. B)
2.3.3 DRAM I/O (Page 11)
" b. VREF (DQ or CA): This parameter corresponds to MR14[5:0] for DQ signals and MR12[5:0] for command / address signals, and defines the target reference voltage level, as a percentage of the I/O voltage. "

On the other hand, the LPDDR4 memory documentation describes the VREF settings for MR12 and MR14 as follows.

The values (%) selectable in the config tool do not completely correspond to the values (%) described in the LPDDR4 memory documentation.

Should the closest values (%) be selected in the config tool as follows?

16.2% -> "16"
25.7% -> "25.6"

Best regards,

Daisuke

  • 0
    TI__Mastermind 35990 points

    Hi Daisuke-san,

    Please note that the MR12 / MR14 values differ depending on whether the memory is LPDDR4 (1.1V IO) or LPDDR4x (0.6V IO). 

    The VREF values available in the SYSCONFIG tool are for LPDDR4 only. 

    Some memories support both modes, so you would need to make sure you are reviewing the LPDDR4 table in the memory's datasheet.

    As a side note, the VREF values will be trained during initialization, so ultimately the tool inputs you are referencing will be discarded. It is typically recommended to leave the VREF values set to the tool default.

    Regards,
    Kevin

  • 0 in reply to Kevin S
    Guru 20175 points

    Hi Kevin-san,

    Thank you for your reply.

    Kevin S said:

    Please note that the MR12 / MR14 values differ depending on whether the memory is LPDDR4 (1.1V IO) or LPDDR4x (0.6V IO). 

    The VREF values available in the SYSCONFIG tool are for LPDDR4 only. 

    Some memories support both modes, so you would need to make sure you are reviewing the LPDDR4 table in the memory's datasheet.

    I understand that AM69 only supports LPDDR4 (1.1V IO).

    Kevin S said:
    As a side note, the VREF values will be trained during initialization, so ultimately the tool inputs you are referencing will be discarded. It is typically recommended to leave the VREF values set to the tool default.

    Are the VREF values (%) set to the corresponding values (%) in the VREF setting table in the memory's datasheet through training?

    Our customer is concerned that the values (%) selectable in the config tool do not completely correspond to the values (%) in the VREF setting table in the memory's datasheet.

    Best regards,

    Daisuke

  • +1 in reply to Daisuke Maeda
    TI__Mastermind 35990 points

    Hi Daisuke,

    Daisuke Maeda said:
    Our customer is concerned that the values (%) selectable in the config tool do not completely correspond to the values (%) in the VREF setting table in the memory's datasheet.

    The values you are showing from the memory datasheet correspond to LPDDR4x. The tool values are for LPDDR4.

    Regards,
    Kevin