active high or active low?
Archiver
Posts: 46,084
If I've got 8 inputs to my stamp that are activated by momentary
pushbuttons, which would be better to do:
Tie the pins high and look for an active low pulse, or tie the pins
low and look for an active high pulse?
It seems like tieing them high would make the stamp have to sink alot
of current. But alot of the sample code I've seen is written for
active-low signals. Is there any advantage of using one versus the
other?
pushbuttons, which would be better to do:
Tie the pins high and look for an active low pulse, or tie the pins
low and look for an active high pulse?
It seems like tieing them high would make the stamp have to sink alot
of current. But alot of the sample code I've seen is written for
active-low signals. Is there any advantage of using one versus the
other?
Comments
andywatson@m... writes:
> It seems like tieing them high would make the stamp have to sink alot
> of current. But alot of the sample code I've seen is written for
> active-low signals. Is there any advantage of using one versus the
> other?
>
>
Not really. If you use a 10K pullup, the Stamp would be sinking about .5ma.
high or low sort of depends on your program and the external device that
takes them low or high. Suppose the only pushbutton you had was normal
open - then you would want to take the line low when the PB was pushed - the
line would have to be pulled high. Personally, I always take pins high where
I have a choice.
Sid
[noparse][[/noparse]Non-text portions of this message have been removed]