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???
05/30/06 09:40
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 		 #117255 - Key bounce.
Responding to: ???'s previous message
With membrane keyboards, I have for years used a 10ms scan and looked for 5 consecutive 'hits' before allowing a valid keystroke. Same for release. It works perfectly, and the 50ms latency is never a problem.
Incidentally, with a membrane that gives little or no tactile feedback, it's always wise to give some sort of feedback to the human. Ideally, a 'bleep' and some sort of visual response (quick display flash, for example). But one or the other, if both not possible.
Dave

List of 28 messages in thread
TopicAuthorDate
passive matrix keyboard readout            01/01/70 00:00      
   yep use the dallas switch debouncers            01/01/70 00:00      
      really, you can't have it both ways            01/01/70 00:00      
   Keypad            01/01/70 00:00      
      what???long weekend maybe            01/01/70 00:00      
         dedicated HW in some '51s            01/01/70 00:00      
   watch human reaction speed            01/01/70 00:00      
   derivative with interrupt on pin change            01/01/70 00:00      
      Or use a maxim 6816            01/01/70 00:00      
         I use SW debouncing...            01/01/70 00:00      
   Can reduce time spent in ISR Key Scan            01/01/70 00:00      
   Use tiny slave micro            01/01/70 00:00      
      Makes sense!            01/01/70 00:00      
         Programming the slave micro            01/01/70 00:00      
            $0            01/01/70 00:00      
               Non-zero cost            01/01/70 00:00      
                  who cares            01/01/70 00:00      
                     The folks who pay will care            01/01/70 00:00      
                        You apply what I said about apples to or            01/01/70 00:00      
                           you missed my meaning            01/01/70 00:00      
                              OK, I'll clarify            01/01/70 00:00      
            Costs? He needs to solve it anyway...            01/01/70 00:00      
               Tme is money            01/01/70 00:00      
                  contradictory            01/01/70 00:00      
         Key bounce.            01/01/70 00:00      
            use a LPC            01/01/70 00:00      
               any MCU will work            01/01/70 00:00      
                  with a LPC you can do either            01/01/70 00:00      

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