Re: [CAD_CAM_EDM_DRO] fire and forget was Re: Black box again

Hi Jon,

I didn't realize it was such a mess! I've got an 'Élan processor on a
board at work, and it's parallel port won't work correctly unless I set
it up for EPP first, then SPP! I tried reading the IEEE1284 (?) spec
before, looks impressive, but I didn't get much out of it. Which chips
are you using, SMS 665, 666? NEC also has some major "glue" chips, but I
think all the ones I knew are OLD now! But then your part would be on
the "device" (peripheral?) end; isn't that a different animal (or
FPGA)?

I'd heard that ECP was out of the game! There were all kind of "port
sharing" stuff for one of the modes, I can't remember now. You're
getting more then one port out of it? And 32 bit "writes"? Sounds
slick! This is the "fire and forget" that makes EPP worthwhile? No
waiting for handshakes? I like it.

Hah! I found the SIIG Cyber 2S1P User's manual. Disk inside. Maybe
there's hope yet! I'd really like to get this board "visible" in DOS.
Not much in the manual, and, I think I've tried the CB20XPC.exe driver
before.

Alan KM6VV


Jon Elson wrote:

>
> Alan Marconett KM6VV 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)?
>
> A total muddle! There are so many versions of these so-called 'specs'
> that it is a real mess. You have to try all the BIOS settings of the
> port to find out which one works! Well, you can write a byte to a
> SPP port in one instruction, without handshaking, but that is not
> a very practical communications protocol.
>
> EPP does allow you to do that, but there are several versions of the
> spec. The 1.7 is not really done right, but the 1.9 version seems to
> have a decent handshaking protocol. Then, there's the DMA
> block transfers to make things really messy. but, the 'messages'
> for real time axis control are too short to make DMA very practical.
>
> Jon