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TDA2EXEVM: SPI chip select setup time

Amar More
Intellectual 280 points

Part Number: TDA2EXEVM

Hello,

 

The SPI chip select setup time(Time since CS goes low to SPI clock) is measured to be around 8.7 micro seconds.

 

But as per the TCAN4550 manual (tcss) value can be as minimum as 25ns.

 

Query 1: How this time can be minimized?

Query 2: Is this configurable using parameter SpiTimeClk2Cs? (As checked in Ebtresos tool for plugins as per delivery mcal_setupwin32_01.09.00.30, this cannot be configured, please find the attached snapshot of tresos window)

Thanks


  • 0
    TI__Genius 12455 points

    Hi Amar,

    On TDA2EX, the "SpiTimeClk2Cs" cannot be used to specify the CS delay. As CS delay is expressed in terms of SPI bus clock by the hardware and not absolute time period.

    Please use "SpiCsIdleTime" instead.

    Value of SPI_DATADELAY_0 configures for 0.5 clock pulse delay between activation of CS and data.

    Value of SPI_DATADELAY_1 configures for 1.5 clock pulse delay between activation of CS and data, SPI_DATADELAY_2 for 2.5 and so on.

    In this particular case, please increase the SPI clock to maximum and set SpiCsIdleTime to SPI_DATADELAY_0. This will ensure the delay between and Data is 0.025 micro-seconds (for 20 MHz SPI bus clock)

    Regards, Sujith

  • 0 in reply to Sujith
    Intellectual 280 points
    Hi Sujith,

    Thanks for the response.

    The SpiCsIdleTime is already configured as SPI_DATADELAY_0.

    But the SPI clock configurations are as below:

    In MCU, the SPI functional clock configured is 48MHz.
    The SpiExtDeviceClockDivider is configured as 2, which is internally considered as 3, hence the SPI clock is 16MHz (48MHz/3)
    We tried to change the clock divider to 1, which will internally be considered as 2, hence the SPI clock shall be 24MHz, but we are not sure how this will function( we shall measure the clock on the hardware once we have the test points)

    Could you please let us know if there is any way in which SPI clock of 20MHz can be generated through EBTresos.

    Regards
  • 0 in reply to Amar More
    Intellectual 280 points
    Hello Sujith,

    Any update on this?

    Thanks
  • 0 in reply to Amar More
    TI__Genius 12455 points
    Hi Amar,

    We checked and it cannot be updated with configurator alone.
    We will have to change the clock source itself to integral multiple of 20 MHz. This change requires updates for multiple other IP's clock confiuration.

    Regards,
    Sujith
  • 0 in reply to Sujith
    TI__Genius 12455 points

    Hi Amar,

    Can we close this thread? Would you have any follow up questions?

    Regards, Sujith