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TMS320F28386D: QSPI

HS FAE Germany
Mastermind 32400 points
Part Number: TMS320F28386D


Tool/software:

Hi,
can the CLB be used to emulate a QSPI interface?

Regards, Holger

  • 0
    TI__Mastermind 19461 points

    Hi Holger,

    We've had discussions on this in the past but the conclusion was that SPI requires too many input/output signals so likely would not be able to implement with CLB (though this is only from discussion and no active efforts were made to conduct an in-depth demonstration). Previous conversation with SPI expert with the following description regarding implementation on C2000

    "For QSPI, Possible workaround is using two SPI modules. One SPI would be configured as controller and generate the SPICLK. The other SPI would be configured as target and receive the SPICLK from the controller. The controller SPI PICO will connect to DOUTA and the target POCI will connect to DOUTB. The operation would be that the program is loaded into the target and then the controller SPI which should trigger the controller SPI to generate the clock and data output as well as the target to generate data output. Note, user needs specifically look at the timing requirements in the DS, specifically on the target side because there is some maximum speed we can run this “QSPI” setup since there will be larger output data delays."

    Regards,

    Peter

  • 0 in reply to Peter Luong1
    TI__Mastermind 32400 points

    Hi Peter,

    > conclusion was that SPI requires too many input/output signals
    so QSPI are 6 signals. Are these too much?

    > For QSPI, Possible workaround is using two SPI modules. 
    I thought to QSPI you need 4 SPIs, right?

    All 4 SPIs are connect to the CLB. So it should also be possible to emulate the QSPI through the CLB.

    Regards, Holger

  • 0 in reply to HS FAE Germany
    TI__Mastermind 19461 points

    Hi Holger,

    There are some restrictions on the actual connections between the CLB and SPI modules. A CLB only has access to 2 direct SPI modules, either A and B or C and D. The other SPI modules can only be supplied through external XBARs like INPUTXBAR or CLBINPUTXBAR to a GPIO. This complicates the timing for the signals due to the added signal path

    Regards,

    Peter

  • 0 in reply to Peter Luong1
    TI__Mastermind 32400 points

    Hi Peter,

    but you have 4 CLB tiles. Can one be used for SPI A+B and the other for C+B and they sync each other?

    Regards, Holger

  • 0 in reply to HS FAE Germany
    TI__Mastermind 19461 points

    Hi Holger,

    F2838x has 8 CLB tiles, you could theoretically use CLB1 to access SPIA and SPIB, and CLB5 for *** and SPID, and there are inter-CLB connections which can transmit signals across the CLB tiles. Suppose theoretically it could work but it hasn't been developed. Also I referred back to the previous discussion I was referring to and it was targeting F28003x which has less CLB peripherals and SPI modules