13 Oct
2002
13 Oct
'02
7:49 p.m.
Hi Joe:
I subscribed and posted to cctech, but found your response in the cctalk
archive. This list is new to me -- do you think I should I subscribe to
cctalk instead of cctech?
>>I have three or four 9915s and a keyboard... I
don't know what the
difference is between an A and a B model... I did make a
schematic of my
keyboard but I haven't seen it in a while...
>>
As I understand it, the 9915A is compatible with the HP-85 (aka HP-85A),
while the 9915B is an 85B. IIRC, the 85B has built-in mass-storage and i/o
roms, and more ramdisk memory than the 85A.
I'd sure appreciate any keyboard info you may run across -- I could program
a little pic to convert a serial keyboard. If this keyboard is used with
other HP machines, other folks might find an adapter handy too.
>>You need to use the HP composite monitors. IIRC
the PN is 82912 and
82913. These are used on the HP 86 and commonly used on the 9000
220 (aka
9920) and are pretty common.
>>
>>There were software developement kits available
that let you write
programs in assembler and burn them into EPROMs that plugged into
a HP-85
type plug-in cartridges (called a Hybrid ROM or something like that) or
directly into the 9915. The EPROMs that are in it are probably Matrix
and/or I/O ROM IIRC. That seems to be standard in the 9915s that I'm aware of.
>>
Yes, I have a programmable-rom-module and assembler rom (but have not tried
them yet). A buddy of mine has managed to read 85 roms and burn them into
eproms for the prog-rom-module. The original 85 roms seem to be special,
and cannot be simply duplicated.
I opened up a rom, hoping to find a standard package, but found a chip
covered in a blob of epoxy, attached directly to a small board. I opened
the rom drawer card, and found that all six sockets are wired in parallel
(no individual enable lines to each). Then I looked at the signals
connected to the rom card connector (using the serial manual's connector
pinout as a reference). The roms have +12V, +6V, and -5V power. There is
an 8-bit bi-directional bus, and four non-overlapping 12V clock signals.
There is a "load-memory-address" line, a "power-on" line,
"read" and
"read-control" lines, and even a "write" line (I don't know why
write is
available on a rom).
This all leads me to believe the roms are pretty specialized. 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. I'm just
speculating, but it would make the roms very difficult to duplicate, since
this is not a standard address-bus/data-bus (or even a typical multiplexed
addr/data bus).
Thanks for the info Joe,
gil
;-----------------------------------------------------------
; vaux electronics, inc. 480-354-5556
; http://www.vauxelectronics.com (fax: 480-354-5558)
;-----------------------------------------------------------
13 Oct
13 Oct
8:34 p.m.
Hi Gil,
I'm sending a copy of this reply directly to you as well as replying on the list so
I can be sure that you get a copy.
At 01:44 PM 10/11/02 -0700, you wrote:
OK that makes sense. Somehow I missed picking that up.
IIRC, the 85B has built-in mass-storage and i/o
I know. HP uses some funky ROMs! The computer sends it the address of the data that it
wants and the ROM (and RAMS) send the data at that address but instead of stopping there
they send the data at the next address and the next and the next, etc etc unless the
computer tells it to stop or sends it a new address. Interesting idea. I suppose it
reduces the otherhead considerably if you're fetching data from consecutive addresses.
I have a Hybrid ROM drawer, actually I think the complete name is Programmable Hybrid
ROM.
How did your buddy manage to read the HP ROMs? With the Assembler?
Hi Joe:
I subscribed and posted to cctech, but found your response in the cctalk
archive. This list is new to me -- do you think I should I subscribe to
cctalk instead of cctech?
I thought that everyone that was subscribed to cctech automaticly got the posts from
cctalk. I was subscribed to both but there was almost no postings on cctech at the time.
>>I have three or four 9915s and a
keyboard... I don't know what the
difference is between an A and a B model...
I did make a schematic of my
keyboard but I haven't seen it in a while...
>>
As I understand it, the 9915A is compatible with the HP-85 (aka HP-85A),
while the 9915B is an 85B. roms, and more ramdisk memory than the 85A.
No, the 85B has more memory (32k vs 16k) than the 85 (aka 85A) but it's standard
memory and not RAMDISK memory. The E-Disk ROM MAY be able to convert all or part of that
to RAMDISK but it would leave you with no user memory. FWIW The 128k memory cartridge is
strickly for RAMDISK memory, it can't be used for regular memory. Also I'm pretty
certain that 85B does not have the I/O and Mass Storage ROMs built-in. The HP-85F has
those built in and it looks like an 85B and says 85B on the front but it should have a
metal tag on the back that identifies it as an 85F. 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.
I'd sure appreciate any keyboard info you may run across -- I could program
a little pic to convert a serial keyboard. If this keyboard is used with
other HP machines, other folks might find an adapter handy too.
I'm sure they would, there are quite a few 9915s out there but AFIK I have the only
keyboard around. I'll see if I can find the schematic. If I can't I guess I'll
have to re-create it. But me every week or two and make sure that I do it else I'm
liable to get busy with other projects and forget it.
>>You need to use the HP composite monitors.
IIRC the PN is 82912 and
82913. These are used on the HP 86 and commonly used on the
9000 220 (aka
9920) and are pretty common.
>>
>>There were software developement kits
available that let you write
programs in assembler and burn them into EPROMs that
plugged into a HP-85
type plug-in cartridges (called a Hybrid ROM or something like that) or
directly into the 9915. The EPROMs that are in it are probably Matrix
and/or I/O ROM IIRC. That seems to be standard in the 9915s that I'm aware of.
>>
Yes, I have a programmable-rom-module and assembler rom (but have not tried
them yet). A buddy of mine has managed to read 85 roms and burn them into
eproms for the prog-rom-module. The original 85 roms seem to be special,
and cannot be simply duplicated.
I opened up a rom, hoping to find a standard package, but found a chip
covered in a blob of epoxy, attached directly to a small board. I opened
the rom drawer card, and found that all six sockets are wired in parallel
(no individual enable lines to each). Then I looked at the signals
connected to the rom card connector (using the serial manual's connector
pinout as a reference). The roms have +12V, +6V, and -5V power. There is
an 8-bit bi-directional bus, and four non-overlapping 12V clock signals.
There is a "load-memory-address" line, a "power-on" line,
"read" and
"read-control" lines, and even a "write" line (I don't know why
write is
available on a rom).
This all leads me to believe the roms are pretty specialized. 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.
Almost certainly. I know that the ROMs in many of their calculators do.
I'm just
speculating, but it would make the roms very difficult
to duplicate, since
this is not a standard address-bus/data-bus (or even a typical multiplexed
addr/data bus).
Yeap!
Thanks for the info Joe,
I hope it helps. Good luck with it.
Joe
gil
;-----------------------------------------------------------
; vaux electronics, inc. 480-354-5556
; http://www.vauxelectronics.com (fax: 480-354-5558)
;-----------------------------------------------------------
10:30 p.m.
gil smith <gil(a)vauxelectronics.com> wrote about HP-8x ROMs:
The roms have +12V, +6V, and -5V
power. There is an 8-bit bi-directional bus, and four non-overlapping
12V clock signals. There is a "load-memory-address" line, a
"power-on"
line, "read" and "read-control" lines, and even a "write"
line (I don't
know why write is available on a rom).
This all leads me to believe the roms are pretty specialized.
Yup, custom for the HP-8x, and CMOS versions for the HP-75. AFAIK they
aren't used in anything else, although sometimes Corvallis division
custom parts wound up in instruments, like the HP-35 chipset (with
different ROM code) in the 1722A oscilliscope.
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.
They all map to the same address range, but have unique IDs that enable
the software to select one and deselect the others.
I'm just
speculating, but it would make the roms very difficult to duplicate,
since this is not a standard address-bus/data-bus (or even a typical
multiplexed addr/data bus).
Yes. I'd be interested in hearing how your buddy did it. I suppose
one could write an assembly-language program to dump ROM data, but
otherwise one would have to build some specialized hardware.
14 Oct
14 Oct
8:55 a.m.
New subject: HP-75 Re: HP 9915A (industrial version of HP 85A)
At 08:31 PM 10/13/02 -0700, you wrote:
gil smith <gil(a)vauxelectronics.com> wrote about
HP-8x ROMs:
For the ones of you that aren't aware of it, the handheld HP-75 is a repackaged
HP-85 with CMOS circuitry. They're so similar that if you ordered one of the Assembley
Language packages that they even included some of the HP-85 manuals! The HP-85 and HP-75
were both designed by the Loveland Colorado instrument group. HP adopted the HP-75 over
the STRENUOUS objections of the calculator group then located in Corvallis Oregon. The
HP-75 was the only calculator produced by HP that was designed by anyone outside of the
calculator group.
Joe
The roms have +12V, +6V, and -5V
power. There is an 8-bit bi-directional bus, and four non-overlapping
12V clock signals. There is a "load-memory-address" line, a
"power-on"
line, "read" and "read-control" lines, and even a "write"
line (I don't
know why write is available on a rom).
This all leads me to believe the roms are pretty specialized.
Yup, custom for the HP-8x, and CMOS versions for the HP-75. AFAIK they
aren't used in anything else, although sometimes Corvallis division
custom parts wound up in instruments, like the HP-35 chipset (with
different ROM code) in the 1722A oscilliscope. 
7:52 p.m.
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