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what is the maximum size of nor flash that can be addressed with emif16 on 6678

Pratheek Suresh
Intellectual 675 points


My project requires nor flash as a boot option for 6678,what is the maximum size I can connect to emif16  .

  • 0
    TI__Mastermind 42545 points

    If you are using a x16bit NOR flash the C6678 can support 32MB.  If you are using a x8bit NOR flash the C6678 can support 16MB.

  • 0 in reply to Bill Taboada
    Intellectual 675 points

    i'm using it in x16 mode, I need help in interfacing it, the address lines i feel is less than required for addressing 32M

  • 0 in reply to Pratheek Suresh
    TI__Mastermind 42545 points

    32MB of NOR flash memory in a x16bit configuration requires 16M or 2^24 of address space.  The C6678 includes the 24 address lines needed to achieve this connection. Remember that EMIFA23 must be connected to the flash A0, EMIFA0 must be connected to the flash A1, EMIFA1 must be connected to the flash A2 etc.  For more details on connecting your flash memory please refer to the External Memory Interface (EMIF16) for Keystone devices users guide.

  • 0 in reply to Bill Taboada
    Intellectual 675 points

    in SPRUGZ3A—May 2011

    1.1 Purpose of the Peripheral

    A total of 256M bytes of any of these memories can be accessed at any given time via four chip
    selects with 64M byte access per chip select. NOR Flash can be used for boot purposes.

    does this mean i can connect 64M that requires one more address line? initially i had selected a 64 M devices for my product and found issues with interfacing, a'm thinking of some work-around also 

  • 0 in reply to Pratheek Suresh
    TI__Mastermind 42545 points

    The statement in SPRUGZ3A is incorrect for devices with a 16bit bus.  As specified in the data manual in the footnote for Table 2-2, the limit is as follows.

    1 32MB per chip select for 16-bit NOR and SRAM. 16MB per chip select for 8-bit NOR and SRAM. More than 32MB allowed by NAND flash.

    The EMIF user's guide is a general document used for all devices that include the EMIF IP.  Most of those devices include a 32bit external data bus which would allow for addressing of 64MB.  Unfortunately the document wasn't completely updated to show the limitations created by the 16bit external data bus.  I will have that corrected in the next revision.