HP 9915A (industrial version of HP 85A)

From: vassilip_at_dsl.cis.upenn.edu <(vassilip_at_dsl.cis.upenn.edu)>
Date: Sat Oct 19 16:28:39 2002

Joe <rigdonj_at_cfl.rr.com> wrote:
> The 85F were delivered as part of various HP test systems and AFIK
> they were never listed separately in the HP catalogs. That's probably
> why few people have heard of them and may be confusing their
> capabilities with standard 85Bs. The 85F is a nice catch IMO, you
> gain two ROMs and don't use up any of the ports on the back.

Yes, the 85F was part of the 3056DL data acquisition system. You can find
a brochure with a description of the 85F config at
    <http://library.hp41.org/LibView.cfm?Command=Document&ItemID=23075>
On page 21 you find the 85F described as:

    Computer with CRT, keyboard, tape drive, graphics, 16K memory, HP-IB
    card, I/O ROM and ROM drawer (all that for just $3485).

There is no Mass Storage ROM and the Adv Programming ROM was a $165 option.

Also since they gave you the ROM drawer, the ROMs would not be inside
the 85F, so you do use one port on the back.

Even the 9915A which contains the ROMs inside the cabinet, has only three
slots, so you appear to lose a slot anyway.

Also, Joe, since you have the programmable-rom-module, can you check inside
to see the type of the translator IC (the one closest to the the edge
connector. I would guess that its either a 1MA5-0101 or a 1MB5-0101.
Further down there should be a 8048 (Intel microcontroller) that does
all the funny address decoding and stuff. At least with most HP85
I/O cards, the funny voltages on the I/O bus are hidden by the translator
chip; on the other side you have industry standard TTL.

Because of the "funny" voltages on the I/O bus, contructing a
programmable-rom-module from scratch would be very difficult, but if we
can use the 1MB5-0101 part (which is found in most adapters) we can
convert some of the zillion 82937 HP-IB adaptors that appear constantly
on eBay to programmable-rom-modules. Then we can all have the EMS ROM
and get rid of the ancient (and huge) 9135A hard disks.

BTW The most impressive of these beasts is probably the 9895A dual
8-inch floppy drive, that is so big that the HP85 sitting on top
looks like a toy.

I have a 20 page brochure on the 9915A. I'll try to make it available
on-line soon. This is where I got the keyboard connector info I posted in my
previous email.

gil smith <gil_at_vauxelectronics.com> wrote:
> There are still a few unknown keys in the main
> matrix though. Pin 25 use is unknown (2.5V). Pin 1 is chassis ground.
As I have mentioned in the previous posting, there is also a speaker
signal on the keyboard connector.


gil smith <gil_at_vauxelectronics.com> wrote:
> Since
> there are no lines to enable a specific rom socket, I think the 85 must
> poll for roms using fixed address ranges or something -- this implies
> that the roms contain address qualification circuitry of some sort.

Have a look at page 5-3 of the HP-85 assembler manual (available on
CDROM from the HP calculator museum - www.hpmuseum.org). It describes
the system memory organization of the HP-85. On page 6-17 the manual
explains how to access other ROMs via the bank-switching hooks.

Best regards

**vp
Received on Sat Oct 19 2002 - 16:28:39 BST

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