Re: [CAD_CAM_EDM_DRO] PCI PARALLEL PORT CARDS FOR DOS CONTROLLER SOFTWARE????...

JanRwl@... wrote:

> Can SOMEone please help: I have built several home-brew (stepper-) CNC
> machines, using the LPT-1 to "step" the X- and Y- axis, and turn the
> spindle-motor on/off, and even activate the tail-stock (pneumatic). I have now a HP
> Pavilion 521n that will PRINT or LIST (BASIC) just fine via its LPT-1 port, but I
> can NOT "toggle" the 8 bits of the data-byte of that via GWBASIC or MSDOS,
> as I could with older Compaq PC's.
>
> Is there some "enable" bit of the LPT-1 I must make HI, to "tell" the PC it
> may turn on/off the data-bits? I can't make them "light a LED test-cable" at
> all on this HP, but I can light one or all-eight with the old Compaq or
> Toshiba computers! Could it have anything to do with "EPP" or "ECP" or whatever,
> and IF so,
> how do I CHANGE those? What is the difference among them?

Most PCs have a BIOS setup screen that you can get to before the
OS boots. Often it needs you to hit Del or F2 at a certain time
in the boot sequence to enter that mode. Then, you can set the
par port addr and modes.

EPP and ECP modes are bi-directional, and could have been left
in input mode by previous software, making your attempt to
output not work. If you can set the port to SPP, that is
output-only, like the original PC and AT. You ought to research
newer parallel ports, there is a book by Jan Axelson called
"Parallel Port Complete", but you can find the register info for
the parport online too.

Jon