Home Page Forums MAME MAME AT&T Blit, DMD 5620 et cetera

This will be in SIMH first. I would certainly like to see it in MAME too, but it has to work reasonably well first.

A braindump on the Blit and 5620.

:
: Blit
:

Wikipedia -- basic info, links to FAQ and video demo (https://www.youtube.com/watch?v=emh22gT5e9k, found in http://doc.cat-v.org/bell_labs/blit/).

Apparently, 'Blits (with 68000 CPUs) came with copious hardware and software documentation (on-line, even!)' (usenet post) but none of that is online; there are a few paywalled articles though:

"The UNIX system: The blit: A multiplexed graphics terminal" (AT&T Bell Laboratories Technical Journal, Volume 63, Issue 8)
"The UNIX system: Debugging C programs with the blit" (ditto)
"Implementation of the blit debugger" ['joff is an asynchronous, source-level, break-and-examine debugger for C programs running on the Blit'] (Software: Practice and Experience, Volume 15, Issue 2, pages 153–168, February 1985)
reference to "The Blit Debugger" articles -- https://blogs.oracle.com/mws/entry/once_blitten
reference to att.blit usenet group [not online] and to "University of Toronto has developed and is currently ['1986] using a 5620(blit) terminal emulator in a ROM cartridge for the [Atari] 520ST" + "Dave Galloway at the U of Toronto Computer Science Research Centre is the person to talk to."

.
. Dot Mapped Display 5620
.

Engineering drawings (include schematics + technical manual) are online -- http://www.brouhaha.com/~eric/retrocomputing/att/5620/att5620_eng.pdf
Computer History Museum has a physical copy -- http://www.computerhistory.org/collections/catalog/102724228
Technical manual for the CPU is at Bitsavers -- http://bitsavers.trailing-edge.com/pdf/w...anual_Jan85.pdf

Other docs were published (306-XXX is AT&T documentation "Select Code") -- these are not online. Manuals for the follow-on models are on bitsavers in http://bitsavers.trailing-edge.com/pdf/att/630_mtg/ and http://bitsavers.trailing-edge.com/pdf/att/730/.

306-120 5620 Dot-Mapped Display, User Guide
306-122 5620 Dot-Mapped Display : software developer application guide.
306-142 5620 DMD Rel. 2.0 Application Development Guide
306-144 5620 DMD Rel. 2.0 Reference Manual
??? 5620 Dot Mapped Display Terminal Service Shop Manual [= AT&T Teletype Manual 625 (Issue 1, July 1984)]

Hardware details that matter for emulation (page numbers are from att5620_eng.pdf):

cpu: Bellmac 32A (WE 32001) or 32B (WE 32100) at 7.2 mhz (xtal 28.8 mhz div 4).
p. 1-1, 1-2
23-bit address bus (8 MB addressable)
p. 1-10
no alignment traps
p. 1-5

memory map:

800x1024 bitmap, 1024x1067 raster, 32 MHz dot clock, 60 Hz field clock
p. 1-20
hsync freq
32.01 kHz
vblank duration
704 ms?

two levels of interrupts, no autovector
p. 1-4
sources of high level [ipl 15] interrupt:
rs232c send buffer ready for data "INT232R";
rs232c receive data available "INT232S";
"PIO00"
p. 1-8
sources of low level [ipl 14] interrupt:
keyboard receive data available;
mouse buttons changed/vblank (60 Hz)/rs232c "INTM0";
cts/dsr/dcd changed;
"PIO01"
p. 1-8

404381 DUART [similar to SCN2681, MC68681] -- clock unknown
p. 1-24
keyboard rx speed fixed at 4800 baud
p. 1-25
interrupts the CPU via INT output ("INTM0" signal) and via OP4..OP6 ("INT232R", "INTKBD" and "INT232S" signals)
p. 1-25
controls the 'reverse video' bit
p. 1-24

ROMs:

Firmware on motherboard -- not dumped, but images of 2.0 variant are in 5620rom.cpio.Z:src/xt/layersys/roms/save; these do not exactly match symbol tables in 5620rom.cpio.Z:src/xt/layersys/rdpatch/lsys.nm.2.0
version 1.0 aka "8;7;1"
version 1.0b(?) aka "8;7;2"
version 1.1 aka "8;7;3"
version 2.0 aka "8;7;5" -- 'corresponds to AT&T 5620 DMD host software Release 2.0'
PALs on motherboard
not dumped
Firmware of "MOS chip" in keyboard
not dumped

.
. WE32000 and 3B2
.

https://en.wikipedia.org/wiki/Bellmac_32
https://en.wikipedia.org/wiki/3B_series_computers

https://github.com/sethm/3b2_rom/blob/master/we32dis.rb
disassembler

.
. Relevant software and stuff
.

Online:

Host software, SDK (SGS -- Software Generation System), demo apps
http://www.brouhaha.com/~eric/retrocomputing/att/5620/
AT&T DMD 5620 series FAQ -- February, 1996
ftp://ftp.cs.utk.edu/pub/shuford/terminal/att_5620_faq.txt
games & programs formerly at ftp://little.nhlink.net/pub/att/dmd/
http://yahozna.dyndns.org/computers/software/3b2/misc/little.nhlink.net/dmd/
dmdtetris
https://groups.google.com/forum/message/raw?msg=comp.terminals.tty5620/H92XPIjyq0I/LroppcP2y7gJ
swarm
https://groups.google.com/forum/message/raw?msg=comp.terminals.tty5620/QIYRGuJilqo/Es5728Nm350J
dmdtobdf
https://groups.google.com/forum/message/raw?msg=comp.fonts/9bZlR6ELwt4/fRg6ZWeK7TQJ
dmdp clone
https://groups.google.com/forum/message/raw?msg=net.sources/VyRhPodF9o8/mB4jOzpYvogJ
dvidmd (via umddvi via CTAN)
http://mirror.hmc.edu/ctan/dviware/umddvi/

crabs
.../little.nhlink.net/dmd/5620/crabs.m.z
http://9fans.net/archive/2008/01/133 via archive.org
http://research.swtch.com/crabs
http://lucacardelli.name/Papers/Crabs.pdf
http://lucacardelli.name/Papers/Crabs%20%28History%20and%20Screen%20Dumps%29.pdf
http://man.cat-v.org/unix_8th/9/crabs
At Bell Labs work is play and terminal diseases are benign (Scientific American, September 1985, paywalled)
gebaca
.../little.nhlink.net/dmd/5620/gebaca.m.z -- runs standalone i.e. not under layers
cent (a centipede game)
.../little.nhlink.net/dmd/5620/cent.m.z
postcard (a neat French post-card with lots of action for your demo file)
.../little.nhlink.net/dmd/5620/postcard.z

Not online:

AT&T UNIX System ToolChest's "dmd-pgmg" package [includes "sam" text editor and "myx" terminal emulator]
https://groups.google.com/forum/#!search/%22dmd-pgmg%22/net.unix/jLMU939d7is/KyCJCAYtFrMJ
vismon and zunk, for the Blit
https://en.wikipedia.org/wiki/Vismon
https://en.wikipedia.org/wiki/Zunk

nuke the smileys
via https://groups.google.com/forum/#!search...z0/tu33IAGjrrYJ)
maxwell (via https://groups.google.com/forum/#!original/comp.unix.questions/zmac3VxmLa8/lMIEPTG8-fQJ)

So are the 68k-version blit ROMs available too, or just the WE32K?

Also, based on the disassembly, the 3B2 POST is actually a WE32K torture test, so that's handy

Only we32k, and it's not actually original, far as I can tell -- makes things a bit more interesting since symbols don't match the code after a certain point.

Seth says he's getting a 5620 soon so that could change.

So is this work in trunk at SIMH, or what? I don't obviously see any WE32k or anything in their default github repo.

In fork at https://github.com/sethm/simh, 5620 bits will soon land into https://github.com/shattered/simh

EDIT: pushed newwip branch. keyboard is missing shift and control keys -- going to replace that with serial_terminal code. F12 is setup and F11 is shift-setup -- triggers self-test. Sample SIMH config:



At higher speed it starts losing chars.

I think most of the breakage (in SIMH itself, WE32K cpu core and 5620 sim itself) is now fixed and 5602 is usable (standalone an d under layers). Still, SIMH has no cpu clock and timing-sensitive apps run erratically. Anyhow:

DMD 5620: jim infested by crabs

Shattered, take a look at the thread just started by Seth on cctlk, in particular the one from Josh

http://yahozna.dyndns.org/scratch/blit/software/

aha, wget -r'ing that as well (I've mirrored other stuff from that site before).

Stupid 5620 tricks while real software isn't running:


DMD 5620: Open Cubic Player