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TM4C1294NCPDT: Maximal SPI speed on TM4C1294XL?

mk
Prodigy 60 points
Part Number: TM4C1294NCPDT

Hi everybody,

does anybody know what the maximum SPI speed for the TM4C1294XL Launchpad is, when operating in master mode?

I assumed 120 MHz / 2 = 60 MHz according to the data sheet but wasn't able to achieve a higher speed than 6 MHz.

Thanks in advance,

Milos

  • 0
    Guru 117855 points

    Does the MCU manual not list your desired, "Max SPI speed as 1/4 of system clock" (and even less when employed as an SPI "Slave.")

    When you note "speed" is this SPI clock rate - or something else?     (your finding of 6MHz seems far too low...)

  • 0
    Guru 27665 points

    mk said:
    wasn't able to achieve a higher speed than 6 MHz.

    As determined how?

    Robert

  • 0 in reply to Robert Adsett
    Guru 117855 points

    Hey - shouldn't you be (back) in the TV studio?    (and working on, "Lessening that accent" - bit more "make-up" could not hurt, either...)

  • 0 in reply to cb1_mobile
    Prodigy 60 points

    Hi cb1_mobile,

    yes it means clock rate

  • 0 in reply to Robert Adsett
    Prodigy 60 points
    Hi Robert,
    through saleae logic analyzer
  • 0 in reply to cb1_mobile
    Prodigy 60 points
    Once again,

    finally the clock rate for SPI on TM4C1294XL is 60 MHz when operating as master. I found it in the data sheet on page 1867.
    Nevertheless this is too slow for my application.

    Thank you guys anyway
    Regards
    Milos
  • 0 in reply to mk
    Guru 10570 points

    mk said:
    Hi Robert,
    through saleae logic analyzer

    While that's a start you do need to measure this with an oscilloscope. A logic analyzer will miss important details. Remember these are RF signals, layout will have an effect on the speed you can achieve.

    Robert

  • 0 in reply to mk
    Guru 10570 points

    mk said:
    finally the clock rate for SPI on TM4C1294XL is 60 MHz when operating as master. I found it in the data sheet on page 1867.
    Nevertheless this is too slow for my application.

    60MHz is too slow? I'm more than a little curious, what SPI peripheral do you have that will operate at 60MHz?

    5MHz upper limit is not uncommon, FRAM is quite fast with some variants going to 20 or 25 MHz but I can't say as I've seen anything specified as faster.

    Robert

  • 0 in reply to mk
    Guru 13040 points

    mk said:
    60 MHz when operating as master...is too slow for my application

    I second Robert's comment here, and wanted to write so that I receive further replies on my mailbox...

    Can you tell us a bit more of your application's requirement? In practical terms, even if you receive data from a SPI bus @60Mhz, if such is anything "close to continuous", there won't be processing power available for ANYTHING else on that MCU... Development of communication at such rate goes to a different forum, and demand oscilloscopes that easily cost 300 times more than the USB Saleae analyzer!

    Anywhere, if you'd like to share the goals, we might be able to provide some further guidance. It's about the whats, not the hows...

    Bruno

  • 0 in reply to Bruno Saraiva
    Guru 117855 points

    *** LIKE ***

    Perhaps the (reporter's mandate) "5 W's & H" applies too. (What, Where, When, Why, Who and How!)

    Providing that detail (best) insures the "story" is told properly... Skimpy detail "eats" responders' time/energy - question "worth asking" (demands) proper effort/composition...