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NOR flash on DM355

SrinivasaSastry
Prodigy 40 points

Any body tried interfacing NOR instead of NAND on DM355 on EMIF interface?

  • 0
    Intellectual 750 points

    Hi,

    Early prototypes of the EVM had NOR flash on the EMIF interface that was multiplexed with the EMIF space used by the DM9000. But I never managed to see it working due a problem with the MSP code.

    Any case, it should not be a major problem to use NOR flash, you will just need to modify U-boot to use the NOR flash and program the flash with some JTAG.

    Regards,

    Diego Dompe

    RidgeRun Engineering

  • 0
    TI__Mastermind 37340 points

    Please note that from a hardware perspective DM355 does not support booting from NOR flash.  As the data-sheet suggest, RBL only supports NAND, MMS-SD, and UART boot modes.

  • 0 in reply to Juan Gonzales
    Intellectual 750 points

    Juan Gonzales said:

    Please note that from a hardware perspective DM355 does not support booting from NOR flash.  As the data-sheet suggest, RBL only supports NAND, MMS-SD, and UART boot modes.

    Mmm, that's not right. The section 11.1 of the sprufb3.pdf (Arm Subsystem User Guide) says that with BTSEL[0:1] = 01, the DM355 boots from AEMIF/oneNAND. NOR memory is directly addressable on the ARM memory space, you you don't need the RBL. Actually that's how the oneNAND boots (because it has a small sector that behaves like NOR flash for loading their own RBL).

    Diego

     

  • 0 in reply to ddompe
    TI__Mastermind 37340 points

    It is not a boot option that is validated (I imagine there is a reason for this) and hence it is unsupported.  This is why it is not mentioned in the data-sheet.  You can certainly try to use it, but if it is not validated and supported in the data-sheet you are doing so at your own risk, assuming you can get it to work in the first place.

  • 0 in reply to Juan Gonzales
    TI__Mastermind 41665 points

    I think there is some confusion, the datasheet explicitly mentions Asynch EMIF boot in section 3.12, which by definition covers a regular old NOR device, so that boot mode is supported. It is an extremely simple boot mode, the ROM is not involved as it just branches to the code at the beginning of NOR, so the big problem I would see with this would be getting your own UBL in the beginning of NOR to run, so from a software aspect we do not really have much support. I think what Juan is trying to get across is that we do not see it used often if ever, at least on the DM355, so in general we suggest you use the boot modes that are found on the EVM (NAND).

    I am curious why you want to use NOR as opposed to NAND anyway, my understanding is that in general NAND is lower cost and higher density.