Re: [CAD_CAM_EDM_DRO] Re: parallel port

In a message dated 5/20/2004 12:44:48 AM Central Standard Time,
fredit@... writes:
Which leads into my next question sorta dealing with XP, how can I toggle a
pin high or low logic?

Fred: I understand only from reading comments over the last several years
on-line that Windows-anything doesn't like to control the bits of LPT-1 except
via formal "normal" PRINT routines. I am NOT much of a machine-code whiz, but
I CAN tell you this:

If you load/use a copy of GWBASIC, a "DOS application", in a BASIC program,
or "direct on-screen command", you can OUT 888, nn - where 888 is the decimal
address of the printer-port data-byte, pins 2-9. You can also OUT 890,nn - but
not all 255 possibilities--only four bits of the eight are "brought out", and
I forget what they are at the moment and am much too lazy to go look. But as
I recall, they are NOT sequential bits. I think pin-1 is one of these.

You can also INP(889), and there are four bits which act as INPuts, and they
are NOT the same four bits, nor are they sequential. Also, one of these
four is "inverted". That is, a LO input to bit-7, as I recall, will cause a 128
to appear in byte 889, while the other three are not inverted.

Here is a link which is source of MUCH more useful info in this regard.
The PC's Parallel Port
Whatever you do, don't let the smoke out of the printer port! Jan
Rowland


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