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Problem about DM6467T DDR bandwidth ！！

yunLing
Prodigy 50 points
Other Parts Discussed in Thread: TSB82AA2

in our project we got video data from DM6467 PCI interface then the DSP process the video data. the video data rate 50MB/s, when we use the 594Mhz DM6467 it is work! now, we go to DM6467T 1GHz , it does not work well. when we setup the DM6467T to 726MHz ,it work well again. In my opinion, it is the DDR bandwidth problem, but when I set these Bus Master Priority Control 0 (like 0x01C4003C MSTPRI0 ) The problem remains unresolved.

how can we do to use the DM6467T ??

  • 0
    TI__Expert 8260 points

    YunLing,

    Are you using DM6467 EVM and DM6467T EVMs? Or are you populaing DM6467 and DM6467T parts on your board?

     

    Regards,

    Srirami.

  • 0 in reply to srirami
    Prodigy 50 points

    Srirami,

    it is our own hardware  board. 

    DM6467 + TSB82AA2 + TSB81B3  

    capture video data from a fireware camera.

    Thanks for your reply.

     

  • 0 in reply to yunLing
    TI__Expert 8260 points

    YunLing,

    Thanks for the confirmation.

    When you change from DM6467 to DM6467T, you need to take care of minimum following things:

    1> Core Voltage (CVdd) need to be changed from 1.2V (DM6467) to 1.3V (DM6467T).

    2> Change input crystal from 27MHz to 33MHz because with 27MHz you can not achieve 1GHz speed (because of PLLM (PLL Multiplier) value limitation of 32 max). The PLL should be configured as follows:

    DM6467:

    PLL0: 27MHz * 22 = 597MHz; PLL1 (DDR2) : 27MHz * 22 = 597MHz (i.e. DDR2 speed: 597/2=297MHz)

    DM6467T:

    PLL0: 33MHz  * 30 = 990MHz; PLL1: 33MHz * 24 = 792MHz (i.e. DDR2 speed: 792/2=396MHz)

    3> DDR2 configuration need to be changed. With DM6467, DDR2 should be running at 297MHz. With DM6467T, DDR2 can run up to 396MHz (with 33MHz input crystal). DDR2 configuration need to be changed from 297MHz to 396MHz. Look at the ARM .gel file at the following Spectrum Digital website for the sample 396MHz DDR2 configuration for the Elpida DDR2 part (EDE1116ACBG-1J-E) used on the DM6467T EVM.

    http://support.spectrumdigital.com/boards/evmdm6467t/

    4> Note that PCI speed is 33MHz on DM6467 and 66MHz on DM6467T. If you are planning to use 33MHz for both DM6467 and DM6467T, there is no change needed. If you want to utilize 66MHz, then you need to pull M66EN up. Look at DM6467 to DM6467T migration guide available at the following link for more details:

    http://focus.ti.com/general/docs/litabsmultiplefilelist.tsp?literatureNumber=sprab44a

    Regards, Srirami.