Re: Parallel Port Interface / correction!

Doug,

Can you explain a little why the SCHMITT trigger is significant (like
what is it)?

TIA
Gary

--- In CAD_CAM_EDM_DRO@y..., Doug Fortune <pentam@h...> wrote:
> Correction! Not a NAND (lost my mind apparently),
> we need an EXCLUSIVE-OR gate as Alan suggests.
>
> But the '136 is not a SCHMITT trigger either..
>
> So here is an alternative (I can't remember the
> chip I used last time, can't find my book...),
> so the suggestion instead is a:
>
> Non-Inverted:
> - 74'341 or 74'344 octal buffer/line driver with Schmitt
> trigger
>
> Inverting:
> - 74'340 octal buffer/line driver with Schmitt trigger
>
> Both have the same pinouts, so if you use a socket, you
> can just switch chips to change between inverting and non-
inverting.
> All three devices are 3 state, but we will just enable them
> permanently (using pin1 and pin19).
>
> Bonus points to Alan for keeping me honest....