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0 pointssydthrowaway4y ago0 comments

What is x? Is it related to human capability?

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Key bounce takes place at timescales far shorter than human reaction times. Typically you'd base the interval on the mechanical characteristics of the keypad.

For instance, taking a look with a scope, if you observe that the signal stops bouncing after 3 milliseconds, it would be pretty safe to accept duplicate keypresses with a 10-ms guard interval.

alar444y ago

You'd have to have two intervals though, one for on, one for off. It bounces both ways. Hardware is more elegant but obviously the tradeoffs depend on what you're implementing.

CamperBob24y ago

It bounces both ways but as long as you don't accept another keypress action (up or down) immediately after the first, you're fine.

alar444y ago

You're fine either way. You either have to poll, or use interrupts. If you are polling, you don't need to debounce the circuit. If you use interrupts, you're going to have a very bad time if you don't. Interrupts are much more efficient. Polling is wasteful.

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CamperBob24y ago

Key bounce takes place at timescales far shorter than human reaction times. Typically you'd base the interval on the mechanical characteristics of the keypad.

For instance, taking a look with a scope, if you observe that the signal stops bouncing after 3 milliseconds, it would be pretty safe to accept duplicate keypresses with a 10-ms guard interval.

alar444y ago

You'd have to have two intervals though, one for on, one for off. It bounces both ways. Hardware is more elegant but obviously the tradeoffs depend on what you're implementing.

CamperBob24y ago

It bounces both ways but as long as you don't accept another keypress action (up or down) immediately after the first, you're fine.

alar444y ago

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