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February 22, 2024
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TIM Capture compare timing resolution/jitter

  • February 22, 2024
  • 1 reply
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I am developing an application using TIM3 with Direct-mode capture compare to measure short pulse widths of 1 to 32 microsec. I am using a Nucleo H7A3ZI-Q board for development. The clock speed is 260 MHz. The Direct capture compare on Ch1 is set the pulse duration by triggering on both input pulse edges.

My question is how much time jitter is there from when pulse arrives to the CC1 input till it is registered in CC1R register? I would guess one clock pulseis needed so the time-jitter would be one clock period. A timer resolution of one clock pulse is given in the specifications (Table 113). It is not clear to me if this also applies ot the capture compare input operation.

This probably needs advice from somebody in STM who has inside knowledge on the timer circuit.

Thanks in advance.

    This topic has been closed for replies.
    Best answer by TDK

    The jitter/uncertainty is 1 timer tick. There is an additional fixed delay of a few timer ticks.

    1 reply

    TDKAnswer
    Super User
    February 22, 2024

    The jitter/uncertainty is 1 timer tick. There is an additional fixed delay of a few timer ticks.

    HWhit.1Author
    Explorer
    February 23, 2024

    Thanks! This answered my question. The fixed delay is no problem for my application.