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How to modify the value of DDR3A_REMAP_EN in the datasheet SPRS836A?

steve zhang
Expert 1690 points

Hi:

In the datasheet SPRS836A,Page 97,table 5-1.it said like this:

From ARM side,the range address from 0x8000 0000 to 0xFFFF FFFF (2GB)  can be mapped to DDR3A

or  DDR3B.it was decided by the value of DDR3A_REMAP_EN .if value = 0,that range was mapped to

DDR3B,Otherwise,value = 1,that range was mapped to DDR3A.

Then my question comes.

1.

What's that value when ARM and DSP power up?

I guessed that value was 1,but I didn't have enough evidence.

I guessed that ARM linux kernel and uboot was running on the DDR3A not DDR3B because of

that value =1.Could you give me some evidence?

2.

How to modify that value of DDR3A_REMAP_EN?

Because I wanted to make ARM linux kernel run on DDR3B not DDR3A.At the same time,

I wanted to make DSP run on DDR3A not DDR3B.

I had searched the keyword _ DDR3A_REMAP_EN in google,but nothing useful.

Thanks!

  • 0
    TI__Guru 50170 points

    Hi, Steve,

    REMAP_EN is a hardware signal and can not be modified from U-boot or kernel. If you need to modify it, it will be from hardware side.

    Rex

  • 0 in reply to Rex Chang
    Expert 1690 points

    Rex Chang said:

    Hi, Steve,

    REMAP_EN is a hardware signal and can not be modified from U-boot or kernel. If you need to modify it, it will be from hardware side.

    Rex

    Hi,Rex:

    ok,Even if the value of REMAP_EN must be modified from hardware side.

    Can you tell me that value when tci6638 power up?

    Because if I know that value ,I will know that From the memory map ,address range from 0x8000 0000

    to 0xffff ffff  can be remapped to DDR3A or DDR3B.

    I don't know how to measure that power level of REMAP_EN pin.Because I am not hardware engineer.

    Hi, Rex,Do you know that value at power up by default?

    Why I cannot find any document which said what's the that value by default or power up ?

    Because that value is very important for me .That value decide how to allocate the DDR memory on board.

  • 0 in reply to steve zhang
    TI__Guru 50170 points

    Hi, Steve,

    From data sheet, DDR3A_REMAP_EN is an Input Terminal Type, and IPD/IPU is DOWN. (Page 39)

    Rex

     

  • 0 in reply to Rex Chang
    Expert 1800 points

    Hi Rex,

    Kindly clarify whether default (IPD) is interpreted as DDR3A_REMAP_EN  '1'.  Is this interpretation in RBL or MCU changes it to '1'?  

    As Steve said, it is an important input for us to know whether to pull it down or pull it up for  interpreting  DDR3A_REMAP_EN  as '1' as we dont have the BMC and MCUs


    Thanks

    Rams

  • 0 in reply to Rex Chang
    Expert 1690 points

    Rex Chang said:

    Hi, Steve,

    From data sheet, DDR3A_REMAP_EN is an Input Terminal Type, and IPD/IPU is DOWN. (Page 39)

    Rex

     

    Hi,Rex:

    Down means 0 or 1?

  • 0 in reply to steve zhang
    TI__Guru 50170 points

    Hi, Steve,

    The answer has been repeated many times in different threads. Could you try to understand what the test tried to achieve in the following thread and draw your conclusion from it?

    http://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/639/t/306482.aspx

    Rex