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Using the TMS320C6748 at it's maximum CLKIN frequency

AmandaD
Prodigy 140 points
Other Parts Discussed in Thread: TMS320C6748

Hi,

I'm planning to use an external 50MHz oscillator with the TMS320C6748 DSP, this is the maximum input frequency when using an external oscillator.

Are there any potential issues that I should be aware of when using the maximum input clock frequency?

Thanks,

Amanda

  • 0
    TI__Guru* 84165 points

    Hi Amanda

    Although I have not seen many customers use this as the input frequency, from a datasheet perspective you are fine and 50 MHz is a supported external clkin frequency.

    I do recommend you to read the PLL clocking section in the TRM , as well as the boot loader application to make sure that you are not missing any key care abouts from your design perspective

    For e.g.

    1) PLL clocking section in TRM , lists the recommended USB input frequencies. 50 MHz is not one of them, so if you need to use USB you will need another clock source for USB

    2) In the boot loader application note, UART boot modes and supported input clocks is listed. If you are using 50 MHz clock input, you will likely not be able to use UART boot mode.


    I also encourage you to use the PLL calculator to make sure you are getting the desired CPU and IO frequencies you need for your design

    http://processors.wiki.ti.com/index.php/Programming_PLL_Controllers_on_OMAP-L1x8/C674x/AM18xx

    Regards

    Mukul

  • 0 in reply to Mukul Bhatnagar
    Prodigy 140 points

    Hi Mukul,

    Thanks for your response.

    We aren't using USB ports or a UART for boot mode.  Our software guy has checked the operating clocks and is happy that we can acheive all of the required frequencies at this input clock frequency.

    Thanks for the link to the PLL calculator; we didn't know it existed and it's been a big help.

    Regards,

    Amanda