Any thoughts how I can implement a glitch free counter that counts 0-9 only ?

Yes I know you can set the output to assert on a count of 10 to reset it back to zero, used this many times.

But in this particular design I feed this count into further detection circuitry but this is being "miss triggered" by the momentary count output of 10, before the counter is reset.

regards

Ian

This particular concept can be implemented by designing rung in such a way that the rung used to increment the count must be disabled when the accumulator reaches the preset value and the reset rung must be enabled when accumulator equals preset so that the count goes from 9 to 0 instead of first going to 10 and then to 0.

However, I have never experienced any glitch in the latter logic. As far as the increment and reset are done in a single scan. But it can produce a problem in interrupt based logic.

KaushalKumarJoshi

This particular concept can be implemented by designing rung in such a way that the rung used to increment the count must be disabled when the accumulator reaches the preset value and the reset rung must be enabled when accumulator equals preset so that the count goes from 9 to 0 instead of first going to 10 and then to 0.

However, I have never experienced any glitch in the latter logic. As far as the increment and reset are done in a single scan. But it can produce a problem in interrupt based logic.

Your implementation in the .lsc file only counts and stays at 9.

I require the counter to reset to zero after 9 without momentarily outputting 10. It is the momentary appearance of 10 that is causing issues further on in processing.

Thanks William, your implantation works fine, no single cycle glitch of a count of 10. Like the idea of converting rising edge to pulse and blocking when count is 9.

I had implemented a correct counter, by my feeling was my solution it too complicated and used too many blocks. Your solution is a lot simpler and when plugged into my simulation works fine, no single cycle erroneous counts of 10 messing up the further processing.

It was the brief appearance of a count of 10 that was being detected as a maximum too large causing the issue.

Putting the glitch free counter in, program behaves as expected.