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AM2634-Q1: Is it possible to use AM2634 with RCCLK_10M only?

Fan_Zhang
Expert 3635 points
Part Number: AM2634-Q1
Other Parts Discussed in Thread: AM2634

Tool/software:

Hi, experts,

There are several clock sources for AM2634.

From below block diagram from TRM, it seems only XTALCLK and EXT_REFCLK can be used as source of PLL, that it is impossible to use AM2634 with RCCLK_10M only.

But, in below table from TRM, RCCLK10M can be the source of R5FSS.

 

Please help to confirm whether it is possible to use AM2634 with internal Oscillator only.

Thanks.

Thanks.

  • 0
    TI__Guru*** 132100 points

    Hello Fan,

    I'd have to circle back with some other experts on the exact reasons but it is not possible to use the internal oscillator only.

    Best Regards,

    Ralph Jacobi

  • 0
    TI__Guru*** 132100 points

    Hi Fan,

    Sorry I realized I dropped the ball on a follow up I needed to make here, will look to have you a final answer by end of the week.

    Best Regards

    Ralph Jacobi

  • 0
    TI__Intellectual 2956 points

    Hi Fan,

    You're right, PLL cannot be sourced from RCCLK10M. The only options available are XTALCLK or EXT_REFCLK.

    Fan_Zhang said:
    But, in below table from TRM, RCCLK10M can be the source of R5FSS.

    Yes, technically it is possible to use RCCLK10M as the source clock of R5FSS. However, the system performance would be very limited against 400MHz performance. Moreover, the RCCLK10M inaccuracy would mean that the system performance is not guaranteed.

    I would also like to point that the R5CLK/SYSCLK actually switches to RCCLK10M in case there's a failure in XTALCLK/ PLL, which is known as limp mode. However, it is just to reach a safe-state and the performance in this state is not guaranteed due to the reason stated above.

    Is there a reason why this is needed?

    Regards,

    Sahana

  • 0 in reply to Sahana H G
    TI__Expert 3635 points

    Hi, Sahana,

    Thanks for clarification.

    Customer is facing issue that the chip stops working, and wants to test with internal OSC to check if the issue is caused by external OSC.

  • 0 in reply to Fan_Zhang
    TI__Guru*** 132100 points

    Hi Fan,

    That wouldn't be a reliable way to make such an assessment. Running the device in limp mode won't allow the full application to run.

    Best Regards,

    Ralph Jacobi