Re: [CAD_CAM_EDM_DRO] Re: LPT1

Mike Delany wrote:

>I have been looking into the same thing. It looks like doing anything CNC
>over USB is pretty iffy. USB uses a packet based transport mechanism that
>can interfere with signal timing. There are supposed to be some
>workarounds, but according to Greg Kroah-Hartman (the guy who wrote the
>linux usb patch), they are not real pretty or efficient. I have thought
>about a PCMCIA to serial or parallel adapter, but I have not looked into
>how timing works on it. I think that you might be better off using a PC
>with a true parallel or serial port.
>
>

PCMCIA (later renamed PC-Card) is basically just a CPU bus interface, so as
long as the register bit and address offset assignment is the same as a
standard
parallel port, and the program can accomodate parallel ports at arbitrary
addresses, it should work. (Note that some DOS and other old programs
may restrict the address to between 100 - 3FF, and the PC-Card parallel
adaptor will often use a much higer I/O address.) I have used a PC-Card
parallel adaptor with other DOS software that used no OS driver, and it
worked just fine, once you figured out the address the PC-Card was mapped
to.

Jon