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CCS/TM4C1294NCPDT: TM4C1294 EPI external SDRAM

Lukasz Huchel
Expert 1420 points
Part Number: TM4C1294NCPDT

Tool/software: Code Composer Studio

Hi,

I have designed my device with Tiva TM4C1294NCPDT. I have a provision EPI header for external SDRAM connection (I was referring to TIDU893 while designing the board). It isn't critical for my device, however, I am interested in exploring this option, since I have never done it before. I have the following question:

- Some time ago I posted a question regarding Altium files related to TIDU893  https://e2e.ti.com/support/microcontrollers/other/f/908/t/697390?tisearch=e2e-sitesearch&keymatch=%20user:245509not available. I looked into BOM which is on TI website and the memory IC used in the design was IS42S163202D (I believe the part number is actually IS42S16320D). This is a 64MB SDRAM (16x32M). In the datasheet 3 clock rates are mentioned: 200MHz, 166MHz and 143MHz. According to the MCU datasheet EPI working in the first mode (EPI_MODE_SDRAM) can handle 64MB but UP to 60MHz. It is my first attempt to use EPI for any purpose. What are the trade-offs of running SDRAM with lower frequency, can it operate correctly??

  • 0
    TI__Guru*** 135355 points
    Hello Lukasz,

    That part number you provided doesn't align with our design. We used a 256kB SDRAM, not 512kB.

    Part number aside, that really isn't a question for TM4C as much as it is a question about that SDRAM and the SDRAM is not a TI device so it's out of knowledge to comment on it's functionality at that level. I would recommend reaching out to ISSI directly about this query.
  • 0 in reply to Ralph Jacobi
    Expert 1420 points
    Hi Ralph,

    Thank you for your answer. I agree, however, I would appreciate if you can provide me the part number that I should consider in the design of my board.

    I have seen in the schematic and BOM of TI design part number: IS42S163202D which is 512Mb (according to datasheet and Digi-Key). Could you clarify which part is used in the design? I plan to use it as a reference. I believe this is the purpose why TI published the notes.

    Also in the firmware published there is 60MHz frequency specified, that is why I am asking.


    Thank you again for help.
  • 0 in reply to Ralph Jacobi
    Expert 1420 points

    What is given  in the design schematic:

  • 0 in reply to Lukasz Huchel
    TI__Guru*** 135355 points
    Hello Lukasz,

    I reached out to the original hardware designer but he doesn't have the exact part number into anymore. He confirmed it should be a 512 Mb 16-bit part though.

    It looks like the TI Design page is not really communicating the size well as it stated 256 Mb which caused me confusion.

    Now that I am aware of this, I think I agree that the part is actually the IS42S16320D you reported. I don't see any other parts which would fit the requirements.

    Regarding 60 MHz, again while it worked for our reference design we aren't in position to comment on the impact that would have to the SDRAM as we don't make that part.
  • 0 in reply to Ralph Jacobi
    Expert 1420 points
    Thank you Ralph.

    I feel more comfortable now with my approach. I will go with IS42S16320D.


    Thanks a lot.
  • 0 in reply to Ralph Jacobi
    Expert 1420 points
    Hi Ralph,

    I got my pcbs this weekend and pluged the SDRAM to my MCU. It worked very nicely.

    Thanks,

    Lukasz