Debouncing multiple switches

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ADWSystems

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I has a series of pushbutton switches that I need to denounce. There's no microcontroller/processor, so software isn't an option. Placing a 555 on each switch isn't really practical. The switch is SPST, leaving the NAND input option (that requires SPDT) off the table. Is the only option left, the RC net fed into an inverter?
 

Will you need the capability to push more than one button simultaneously?
 
Have a look at MAX6816/17/18. They are, respectively, single, dual, and octal debouncers.
 
Just use a large RC filter on each input. You won't get much smaller or cheaper than 1 R and 1 C per pin. And you get some extra ESD protection etc which is always handy on pushbuttons.
 
This chip can take a momentary pushbutton input and de-bounce 8 switches, it is a 18 pin dip package
 
Mike2545 said:
This chip can take a momentary pushbutton input and de-bounce 8 switches, it is a 18 pin dip package
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If I'm understanding the datasheet correctly, this IC toggles the output. So a single button press will be debounced to 25 ms but then the output of the IC will stay high until the button is pressed again. So, it has the effect of turning a momentary pushbutton into a latching push button.
 
Yes, those outputs are toggled. Do you want the outputs to simply follow the input with 25-msec propagation delay?
 
ADWSystems said:
I don't know about vne147, but I need them to follow the input.
Click to expand...

I don't know about me either. Have you thought about using a D flip flop and just clocking it slower than the debounce period? It wouldn't be perfect but it might be good enough. You could use 2 flip flops in series if you needed it to be better.
 
I was thinking about that last night. I think they make, but I haven't had a change to look for, a octal latch chip. 8-inputs with 8-outputs latched on a CLK signal. What does anyone else think about this idea?
 
Are there any other sources than Jameco? They have a $25 minimum order and they don't stocking any of the other parts I need for the project.
 
If I used a 555 timer with a 25ms one-shot and a 16v8 PLD, do you think I would be able to accomplsh the same thing as the EDE2008?
 
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