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

Alan Marconett KM6VV wrote:

> 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!

Wow, that's wierd! I have a problem with the current software, that
if the system has used the parallel port to print, then EMC won't work
until you reboot. I haven't found out what curious state gets changed
that I'm not aware of, yet. I will have to dig sometime and try to
identify why that is, but it shouldn't be a big problem for most users.

> 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?

It looks like the SMS FDC37C665GT and ...666GT are very similar is
the register definitions, I'm pretty sure my software will run on either
of them. it should also run on most of the other EPP chips as well, as
long as they adhere to the register definition standard from Microsoft.

> 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)?

But, the software needs to configure the PC's parallel port properly and
then transfer commands and data to the "device" end.

> 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.

Essentially, you get 256 possible devices, or think of it as being
able to address 256 byte-wide registers out there on the end of the
parallel port cable, and transfer a byte (or even 2 or 4 bytes) with
one single instruction. Also, by putting an address counter into the
device, you can write or read several bytes in a row to/from
consecutive addresses with one instruction per byte.

> 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.

Well, I really can't get too excited over DOS, anymore. Good for
writing really quick diagnostic programs in Turbo Pascal, but not
a whole lot else.

Jon