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TMS320F28377D: Max amount of external memory via EMIF?

dduncan
Intellectual 315 points
Part Number: TMS320F28377D


What's the maximum amount of SDRAM that can be added to a F28377D design using EMIF?


My current understanding is that theoretically it's 256MB (2 gigabits).  This would be using 13-bit row addressing, 11-bit column addressing, 4 banks, and a 32-bit data size, via EMIF1: 2^13 * 2^11 * 2^2 * 2^5 = 2 gigabits.  It seems that EMIF2 could be used simultaneously, but that because some of the address lines are shared, it'd realistically be unlikely to be worthwhile.


Then there is the practical concern of finding memory to match the above parameters.


Is all of the above accurate?  So far, I haven't found anything beyond 512-megabit SDRAM from Micron, so if a larger size is supported and someone has a product suggestion, that'd be appreciated.

-David

  • 0
    TI__Guru** 115611 points

    Hi David,

    My current understanding is that theoretically it's 256MB (2 gigabits).  This would be using 13-bit row addressing, 11-bit column addressing, 4 banks, and a 32-bit data size, via EMIF1: 2^13 * 2^11 * 2^2 * 2^5 = 2 gigabits.

    Technically that is correct but today I don't think you'll find any memory device of that size in market.

     It seems that EMIF2 could be used simultaneously, but that because some of the address lines are shared, it'd realistically be unlikely to be worthwhile.

    Yes, EMIF2 can be use simultaneously. Which address lines are shared? Only data lines are shared so if using EMIF1 and EMIF2 simultaneously then EMIF1 has to be used in 16bit mode.

    Then there is the practical concern of finding memory to match the above parameters.

    That is correct. Please use max size device available in market.

    Regards,

    Vivek Singh

  • 0 in reply to Vivek Singh
    Intellectual 315 points

    Vivek Singh said:
    Yes, EMIF2 can be use simultaneously. Which address lines are shared? Only data lines are shared so if using EMIF1 and EMIF2 simultaneously then EMIF1 has to be used in 16bit mode.

    That's what I was thinking of.

    Thanks for the info!