Query for dec teleprinter roms

william degnan billdegnan at gmail.com
Mon Sep 21 23:10:34 CDT 2015

Thanks.  I will see what I can do.

Bill Degnan
twitter: billdeg
On Sep 21, 2015 11:02 PM, "Jonathan Gevaryahu" <jgevaryahu at gmail.com> wrote:

> There isn't a complete archive of these ROMs in existence currently. Pete
> Turnbull's site does contain an archive, but it isn't anywhere near
> complete. The drivers in MAME/MESS also act as a sort of archive as well.
> The direct prompt of this request was the desire to get one or more of the
> dot matrix teleprinters running in MAME/MESS, the progress of which can be
> seen at
> https://github.com/mamedev/mame/blob/master/src/mess/drivers/decwritr.c ,
> with the LA120, but the ROMs I have right know for the LA120 fail their
> built-in checksum test, so I'm stuck at a development impasse until I can
> get some more roms to work with (or correctly re-dumped copies of the
> existing roms).
> The end result of what I'm trying to do would hopefully look something
> like this: https://www.youtube.com/watch?v=l20V7f2sM8c
> On 9/21/2015 3:19 PM, william degnan wrote:
>    What are you going to do with these?  Is there a ROM archive for DEC
>    printer ROMs?
>    On 9/21/2015 3:14 PM, Jonathan Gevaryahu wrote:
>>     Does anyone have an LA36, LA120 or LAS12, LA34, LA100, or LA210
>>     somewhere which they could dump the ROMs from?
>>     Notes:
>>     The LA36 uses several proms for its discrete cpu, and 2 character
>>     set roms which I believe have an 'odd' pinout.
>>     The LA120, one of the roms on the '2 rom version' is an 8k 2364 24
>>     pin chip which is a bit annoying to dump, since you either need a
>>     2364->2764 24->28 pin adapter, or (better) a programmer which can
>>     dump MC68764 or MC68766 24-pin 8k eproms (which have the same
>>     pinout as 2364). The other rom on the 2 rom version is a 2k 2316
>>     24 pin chip.
>>     The oldest LA120 version uses 5 roms, all 2k 2316s. The code on
>>     the 5-rom version and the 2-rom version may very well be the same
>>     (the first 4 2k chips consolidated to one 8k chip), I'm not sure.
>>     Would be nice to get dumps of both versions.
>>     The LAS12 uses different code from the LA120 and to the best of my
>>     knowledge all LAS12s use 2 roms, one 8k and one 2k.
>>     LA34, theres at LEAST five firmware versions, almost certainly
>>     six, and possibly as many as seven. There is also a special
>>     firmware for a 'rom expansion' daughterboard.
>>     The 1978 LA34 "54-13374" motherboard has a bizarre Intel i8355
>>     mask rom+io chip in it, plus a separate rom as well. (there are at
>>     least two versions of said i8355+rom firmware). Dumping the i8355
>>     is not for the faint of heart, it would likely be easier to insert
>>     a 'dumping program' eprom into the single rom's socket, and use
>>     the LA34's cpu to spit its own rom contents out via serial.
>>     The 1980 LA34 "54-13747" motherboard lacks the i8355 and uses 2 or
>>     3 mask roms or eproms on it instead (and 74xx logic for the i/o).
>>     There are at least three rom revisions for this, possibly four or
>>     five.
>>     LA100 (AKA LW100)... I have no idea. There's definitely at least
>>     one rom revision. Also to the best of my knowledge neither the
>>     maintenance print set nor the technical manual for the LA100 are
>>     scanned (they certainly don't appear at
>>     http://bitsavers.trailing-edge.com/pdf/dec/terminal/la100/ ),
>>     which makes it difficult to know.
> --
> Jonathan Gevaryahu
> jgevaryahu at gmail.com
> jgevaryahu at hotmail.com

More information about the cctalk mailing list