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c6747 EMIFB Settings

sudheer thota
Intellectual 355 points

Hi,

1) When i change the  EMIFB Clock from 133 to 60MHz, Do need to reconfigure above SDRAM settings? If So could please let me know the correct settings for configuring to 60MHz.

Here is the Datasheet for SDRAM

http://www.issi.com/pdf/42S32400E.pdf

I'm using AISGen tool for c6747 Peripheral initialization & Configured SDRAM for ~133MHZ and using Following Setting for SDRAM

                SDCCFG: 0x00018420

                SDCTIM1: 0x32912A10

                SDCTIM2: 0x70090005

                SDRFC:  0x000003FA

Thanks,

Sudheer

  • 0
    TI__Guru**** 176281 points

    Sudheer

    For changing the EMIFB clock frequency from 133MHz to 60MHz, please refer to the C6747 TRM section 6.3.2: http://www.ti.com/lit/ug/spruh91a/spruh91a.pdf

    When I did the calculation, the SDCTM1 needs to be programmed with the value of 0x10912A08 and SDCTM2 needs to be programmed with value of 0x6809005.

    Thanks
    David

  • 0 in reply to David (ASIC) Liu
    Intellectual 355 points

    Hi Liu,

    Thanks for your reply. 

    Small clarification. are these values "SDCTM1" & "SDCTM2" you mentioned for 60MHz? 

    Seems the values i'm using are wrong for 133MHz. Could please verify the Values. I would like to take expert opinion.

    Is SDRFC also changes when we change 133 to 60MHz?

    For 133MHz, Currently i'm using following values

                    SDCCFG: 0x00018420

                    SDCTIM1: 0x32912A10

                    SDCTIM2: 0x70090005

                    SDRFC:  0x000003FA

    Last Question what will be the impact / artifact due to programming wrong values? Seems the code is working. 


    Thanks again,

    Sudheer

  • 0 in reply to sudheer thota
    TI__Guru**** 176281 points

    Sudheer

    The value I provided is for 133MHz, not 66MHz timing. If it is a timing issue, then you probably would see read/write error. Would you please try the new value in your code?

    SDRFC would also change when you change the clock rate.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Intellectual 355 points

    Hi Ti support,

    Could you please share any sort of tool/spread sheet to calculate these settings by my self?

    I need to calculate the setting for this part while configured to operate at 131.1M and MHz..

    Thanks,

    Sudheer

  • 0 in reply to sudheer thota
    TI__Guru* 83745 points

    Hi Sudheer

    We are working on a calculation spreadsheet but this will likely be available in a week or so.

    Your request for help on timings has been routed to us by James Kay, we will try to provide assistance in the next couple of days.

    Regards

    Mukul