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MPC57XX Glitch Filter : Minimum glitch period filter

Question asked by Christopher Holland on Feb 28, 2019
Latest reply on Mar 8, 2019 by David Tosenovjan

As a follow-up to an earlier question about 'n' in the following equation:  [Filter Period = TCK*MAXCNTx + n*TCK]


I have calculated the minimum filter period.

      Prescaled Filter Clock Period TCK = T(IRC) x (IFCP + 1)
      T(IRC) = 62.5 nS (F = 16 MHz)
      TCK*MAXCNTx : 62.5 * 4 = 250 nS
      n*TCK: 62.5 * 4 = 250 nS
      [Filter Period = TCK*MAXCNTx + n*TCK]: 250 nS + 250 nS = 500 nS


Now, I am curious to think that, at the very least, this minimal glitch filtering should be applied to all Interrupt filters regardless. Extended period filtering can be applied as necessary.

I believe this equation also determines the minimum interrupt  period. Though a interrupt at this period would take most of the processors cycles and not leave any for other tasks.


Am I correct in this assumption?


Thank you,