re:fire and forget was Re: Black box again

Hi Ballendo,

Yes, I see your usage now. That subject actually came up earlier today
here at work! I had specified a parallel port to be added to a new
board design intended for an imbedded product, for "test purposes" ;>),
and someone in marketing must have seen it, and decided that the product
needed a parallel printer port in addition to the serial port used for
printing on our "PDA" line (Personal Diagnostic Assistant ;>) ).

Anyway, as the BIOS I wrote for this product doesn't support a parallel
port, I was trying to explain to a new hardware engineer that he (they)
couldn't just "send ASCII text" (he wanted to test it) to the printer
plugged into the parallel port! And although we had tested the data
lines, cmd lines, and status lines, if he wanted to see a printer run,
then I'd have to write a "driver" for it (the "REAL" app for the
hardware has a "printer package" that we link in, and IT talks to the
current serial port and will talk to the new parallel port it's self!

Myself, I think this little board with graphics LCD, 13-key keyboard,
Disk-on-chip, PCMCIA, serial and PARALLEL ports has some OTHER uses!

I completely missed the original thread, and the outboard controller.
Yes, I intend to do some "fire and forget" on this board (bit banging).

Thanks for the explanations,

Alan KM6VV (missile away!)

ballendo@... wrote:

>
> Alan,
>
> I am speaking of using the p-port hardware from "user-written"
> software which writes the port bits directly (not through dos or
> windows). The EPP and even the SPP have "printer" calls which ARE
> handshaked, that is why there are pins defined for strobe and ack.
>
> When we use the port for cnc, we usually bypass these routines so
> that we CAN "fire and forget". We get to use the strobe and ack lines
> for additional I/O as a side benefit.
>
> Hope this helps.
>
> Ballendo
>
> P.S. In this thread originally, "fire and forget" was referring to an
> outboard controller. It simply means that the control is asynchronous
> (we send commands out when we need to, we get commands back when IT
> needs to). We ASSUME that our requests are fulfilled by the
> controller (that is the essence of the "forget it" part). If not, the
> controller will/may send us an "oops" command or bring a certain pin
> hi(or low).
>
> --- In CAD_CAM_EDM_DRO@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:
> > Hi Ballendo,
> >
> > OK, I get it. But SPP (Standard Parallel Port) doesn't do that for
> you,
> > at lest for type 1 (IBM). Type 2 or 3 (IBM DMA) might. Aren't you
> > thinking of EPP (Enhanced Parallel Port)?
> >
> > Alan KM6VV
>
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