Homebrew PCBs

On Sun, 12 Oct 2003 03:11:09 -0000, ghidera2000 <ghidera2000@...> 
wrote:

> I'm just finishing up the design for an A3977SED based controller board 
> but I'm a bit confused about the parallel port connections.
>
> Can the parallel port drive logic high and low or does it just go active 
> low (sinking) and high-Z? i.e. Do I need pullups to generate logic high, 
> or can the parallel port handle this just fine?
>
> I plan on pulling Enable high on the board and setting it to active low 
> in the software. That way if the cable pops out I know the drives will 
> stop.
>
>
parallel port drives high..
I know some which have connected leds direct to it and it survived..
so it is current limited somehow.

if i remember correct on old mainboards one could see the pullups (&replace 
them)

You need no external pullups..

(This is only MY experience, not any standards or something, just what i 
saw on various ports)

st