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TMS570LC SPI - parallel mode in connection with NOR flash

Jiri Janacek
Genius 3315 points
Other Parts Discussed in Thread: TMS570LC4357

Dear all,

I would like to discuss a way how to connect the latest Hercules microcontroller TMS570LC4357 in the SPI parallel mode with NOR flash Micron N25Q00AA operating in the Quad mode/protocol.

If I understood correctly, there is a fundamental obstacle to connect the micro with the flash:

TMS570LC4357 supports the 4-datachannel SPI5 (transferring 16bit word) - signals SIMO[0..3] and SOMI [0..3]. But the memory N25Q00AA uses signals DQ0 - DQ3 as bi-directional I/O pins.

Do you have any idea how to configure and establish the connection between those two devices? In the HW point of view as well as within  the SPI peripheral setting?

Many thanks in advance,

Best regards, Jiri

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  • 0
    TI__Genius 11645 points

    Jiri,

    One of our SPI expert will help you with this soon.

  • 0 in reply to KARTHIKEYAN RAJAMANICKAM
    Genius 3315 points

    Dear Karthik,

    thanks for your reply.

    My expectation is that your expert will confirm that only way how to connect this memory is using non-parallel mode (1-datachannel). But I will be happy if I am wrong ;-)

    Best regards, Jiri

  • 0 in reply to Jiri Janacek
    Genius 3315 points

    Dear Karthik,

    have you received some information by your SPI expert regarding this topic.

    Thanks a lot,

    Jiri

  • 0 in reply to Jiri Janacek
    TI__Genius 11645 points
    Hi Jiri,

    We had a quick synch-up on this with our experts and looks like we cannot use the parallel mode since the data doesn't come out packed as you would expect for a NOR flash in Quad mode. We are looking to see if there are other options to hook-up a Nor Flash. Will keep you posted if there are other options.
  • 0 in reply to KARTHIKEYAN RAJAMANICKAM
    Genius 3315 points

    Dear Karthik,

    thanks for your feedback up to now. I am worry about there is an alternative way how to handle this interface but I will be happy with your any proposals.

    Best regards,

    Jiri

  • 0 in reply to Jiri Janacek
    TI__Guru 68920 points
    Hi Jiri,

    We've used the EMIF before for SPI flash in quad mode, because the << 4 operator is cheap. But the way MibSPI data is interleaved in parallel mode, the operation you'd need to undo this would be something that takes a value like 0x00000000F and turns it into 0x01010101 and I don't think that this is cheap (cycle wise). And if it's not cheap that way - we're thinking it defeats the purpose of QUAD serial flash.

    We'd almost recommend EMIF but there are errata on the EMIF, specifically with extra chip selects during reads so this we're thinking is a no-go.

    Assuming you are asking for quad serial flash for speed reasons ... and you wouldn't be happy with say a 5MHz serial clock. Is that correct?
  • 0 in reply to Anthony F. Seely
    Genius 3315 points

    Hello Anthony,

    using the EMIF seems to be a good hint but you are right there are errata issues regarding data storing (unaligned data) via EMIF etc. In addition we do not want to occupy the EMIF by this kind of data (other devices are connected via EMIF).

    You are right - there was an interesting option to use the quad mode but it was not the major argument to choose this memory type. I think we can work with the maximal frequency of the SPI module (20 MHz) and set the multibuffer mode to almost satisfy and fulfil our requirements.

    Thanks for your support!

    If you do not have further ideas in your mind, I will verify your post and close this thread.

    Best regards,

    Jiri

  • 0 in reply to Jiri Janacek
    TI__Guru 68920 points
    Hi Jiri,

    No other ideas come to mind unfortunately. At least none that would outperform (or come close) to the MibSPI running at 20MHz.