software switch debounce time???????

[d@nny]

hello!
what is the safest time to key debounce?
i am using this technique
key pressed detect
wait 10ms
check state of key
key is pressed = process the data
wait for key released
key released = wait 10ms = returned
is this the safest time or i need to increase it for more accuracy
thanking you in anticipation

 

[andre_luis]

10ms seems to be reasonable.

However, the method of keep waitiing in a closed loop, can waste a lot of processing of CPU.
Better to handle it by interruption timming.

+++

 

[alexan_e]

You can also use polling using a timer interval so that the code execution doesn't stop while waiting.
If you set a timer to give an interrupt every 10ms then you can read the input and set a flag variable with the button state and then read that flag in the main loop and do the rest.

Alex

 

[jpanhalt]

Here are a couple of nice links to Ganssle's studies. The first studies the time needed and gives data.

The second gives some software advice.

Debouncing
Debouncing

John