HP92198 HP-IL 80-column video interface

[Garth]

Many 41 users are unaware of the HP92198 80-column video interface that Mountain Computer made for HP.  I thought I should post a picture here that I took a few months ago during an HP-41cx project.

There's not much alpha shown there, but it does show the capability.  I also didn't need 80 columns for what I was doing at the time, but you can see the clarity anyway.  And yes, the 41 can do any number of columns you could want, using ACA (accumulate alpha) and related functions.  Here's the front of the video interface box itself:

I refreshed the two EPROMs recently.  One has the program material, and one has the dot information for forming the characters.  It occurred to me that you could have various EPROMs for various character sets, and swap them out, or have them piggy-backed with only the OE\ pin individual to each, and use a thin wire to connect that to a DIP switch to select the one you want.  I also kept Intel Hex files of the EPROMs so I could restore them if they did go south, or email them to someone who needs to re-program theirs.

[floppy_stuttgart]

Is it possible (and how) to do
XEQ DIR
with such Video connected at an HP41?
(it means the HP41 would access the 2 devices in the loop: a video and a drive)
Without I/O Module?

[Garth]

Is it possible (and how) to do
XEQ DIR
with such Video connected at an HP41?
(it means the HP41 would access the 2 devices in the loop: a video and a drive)
Without I/O Module?

Yes, and you can have the printer or monitor list the directory entries automatically.  See the manual at http://www.hp41.org/LibView.cfm?Command=View&ItemID=436, and specifically the page at http://www.hp41.org/LibView.cfm?Command ... leID=14721

You can of course have lots of devices on the loop at the same time, including lots of mass-storage devices, and address them individually with SELECT.

[Garth]

To add to my reply above:
When you say "I/O module," I assumed you meant the Extended I/O module.  You do of course need the HP-IL module to interface to the HP92198.  Also, the HP-IL manual talks about printing the directory on a printer-class device, and I originally wrote "printer" and then changed it to "printer or monitor" without trying it.  The HP82198 manual does say however, on page 2-4, that it is indeed a printer-class device; so I suspect it can display the directory if it's the first printer-class device on the loop.  A question I have now has to do with other ways of printing, since I haven't used an HP-IL printer in decades, only my Epson printer, going through either the HP82165A HPIL-to-parallel interface converter, or the FSI164A (like the HP82164A) HPIL-to-RS232 interface converter, and these converters are of course not printer-class devices.  I'll have to dig out a tape drive to actually try it, which won't happen today.

[floppy_stuttgart]

It would be nice if you test:
a) HP41 and HPIL (no I/O Module in HP41)
b) first device in the loop is the screen
c) second device in the loop is a cassette drive
.. if the content of the cassette drive can go as output into the monitor.
From what you informed, I suppose yes (the screen is a simulated printer).

[Garth]

I cannot separate the HP-IL module from the Extended I/O, since they're integrated.  I bought them that way, brand new, from EduCALC, about 1986, so they only take one port.  I could try b) and c) in the next few days, if there's any point since I don't have a separate HP-IL module.  It would be nice if the 41 had a DISPLAY IS and a PRINTER IS function like the 71 has.

[jeffcalc]

Is it possible (and how) to do
XEQ DIR
with such Video connected at an HP41?
(it means the HP41 would access the 2 devices in the loop: a video and a drive)
Without I/O Module?

The DIR command really does that: print the directory of a drive to a printer (if present in the loop).
A display device (video interface) acts as a printer for the HP-41 print commands.
This is described in the HP-IL module manual page 46, probably not very clearly for most users:
"A standard printer type device [for the HP-41C] is one whose accessory type is a number from 32 to 63".
This section 4 of the HP-IL manual is worth re-reading, when not sure about HP-IL device behaviour.

The HP82198 manual does say however, on page 2-4, that it is indeed a printer-class device

the screen is a simulated printer.

The 92198 manual doesn't say exactly that. It talks about the HP-41 and printer type devices.
The 92198 is a display-class device, it acts with the HP-41 as a printer type device but it is more than a printer-class device.
For instance, a display device supports cursor control. Few HP-41 modules provide commands to manage it, one is the French Paname ROM.

J-F