A little while back I assembled a test board to check I could get clean pulses from a couple of mechanical rotary encoders using some simple debouncing and logic to also get separate outputs for each direction plus an output for the push switch of one. The schematic is attached. When I check the outputs on the scope they look perfectly clean with one pulse for each detent. However, when I incorporated this into a circuit that uses 74HC193 synchronous up/down counters I get increments / decrements of one or more (usually more) than one for each pulse. I'm really stuck on this and even tried using the pulses to clock a breadboarded CD4040 circuit - same result, it counted up sometimes one more often more than one for each pulse.
I know rotary encoders can be a pain to get clean pulses but my scope shows the pulses are just that so I'm at a loss to figure this out. I'm hoping somebody here can give me a pointer as to where the problem might lie.
The test board:
I know rotary encoders can be a pain to get clean pulses but my scope shows the pulses are just that so I'm at a loss to figure this out. I'm hoping somebody here can give me a pointer as to where the problem might lie.
The test board:
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