"Programmer Electronic Control"

PartNo. 51-019-02, NSN 1680-99-652-3410,
Supplier K0656, Marconi Avionics, UK

(Restoration of a vintage rugged computer from the Tornado aircraft)

- The complete Story in pictures, by Erik Baigar, www.baigar.de -

News/History

30.05.2010: Added info on the inverter, the UK-Trip and latest achievements with the new PEC setup.
30.01.2010: Added first blinkenlights related information and pictures of the newly acquired waveform
generator from the early versions of Tornado.
13.12.2009: Latest achievements added to the Time-Line and supplied the "gallery" with new pictures.

Contents...

Results of the reverse engineering efforts
Logbook listing the major steps
Roots of the unit / architecture
Suspected original use
Emulator for the "big brother"
External information
MANY THANKS
Picture "gallery"
Older history

1. Result of the reverse engineering efforts from 2004 until today:

Command reference of the "Programmer Electronic Control"
as I deciphered and named the commands. This contains lots of technical information,
timings, pin-outs and much more. Current status: The 12-bit processor is fully
operational - even interrupts and the IO system are working now. A "hello world"
is perfectly running on an attached LCD display and the unit can control a
CalComp M84 pen plotter.

Photo Suite of all the printed circuit boards of the unit:

(1) Driver Board, 1680-99-646-6754; (2) Data Board, 1680-99-646-6755; (3) Core Memory, 5841-99-652-3386;
(4) Driver Board, 1680-99-646-6754; (5) Control Board, 1680-99-646-6753; (6) Data Register, 229-013909;
(7) Data Register, 229-013909; (8) Control Register, 229-013551; (9) Function Decode, 229-013549;
(10) Processor Timing, 229-013547; (11) RxTx Interface, 229-013545; (12) Serial Parallel Converter, 229-016304;
(13) Decode and Interrupt, 229-013905.

The unit consists of 15 boards of standard size 100mm*160mm, containing a total of 497,
mainly standard mil-spec TTL chips. All of them are identified, even the exotic four
custom ones and data-sheets are available. Here is a

Collection of technical information

on all chips used in the PEC's processor including statistics of the date codes.

2. The Chronology of the project...

...starting in 2004 is a longer story. Thus the complete diary is located on a seperate page, listing all major steps
and achievements during the years of reverse engineering: TimeLine. This page contains and explians
many of the pictures shown in the gallery below. The latest achievements from this logbook are the following:

1/30/2010	Recycled some venerable switches and buttons for the PEC's blinkenlights to be build by dismantling a "Data Monitoring Unit", NSN 6625-99-6559680, manufactured by Smiths Industries under part. no. 2001TE/1. Rumors have been, that this was used on some computer within the early Harrier VSTOL aircraft. The chance of finding such a beast is zero and thus the switches will get some new job soon.
3/26/2010	After receiving last parts for the housing the 3 phase inverter is completed now. This inverter is based on three audio amplifiers, each being capaple to deliver 60W of power. Three transformers allow different voltage ranges (0-120VAC and 0-240VAC) by switching from the star to a delta configuration. Initially the 24V supplies have not been strong enough for a continuos operation of PEC, but with the new supplies this works very well.
4/14/2010 to 4/18/2010	Had a very exciting second visit to the UK: Visited the museum in Bletchley Park holding an Elliott 800 in working condition and a non working 905. Lot of time is spent by volunteers in maintaining the wonderful collection of avionics items at the Farnborough Air Sciences Trust Association which was well worth the visit as was the excursion to Kent to visit the Rochester Avionics Archives holding many items manufactured during the long history of the vintage Elliott Brothers Ltd. to become part of the current BAe Systems. Another very impressive event was the demonstration of Roger's huge ICT1301 machine which Roger and Rod lovingly call Flossie. Due to the vulcanic eruption the schedule of the weekend got severely disturbed, since my wife was not able to join me for sightseeing in London. So after a visit in Cosford to see the mighty TSR2, I spent the sunday for a strange journey back to Munich: Travel took 24 hours by 10 different means of transportation instead of 2h time of flight. But the highlights of this journey definitively have been the nice evening with Peter and the time with Terry and Val - Many Thanks!
5/30/2010	After struggling with the Altera Quartus 9.1 software for several weeks I got a fix of the problem from Altera in April. Now there is progress with the actual setup again and on 19th of May the word generator module was working for the first time. The two transputer setups work in parallel now: The old one wired to the backplane still controls PEC and is able to access the core memory. The new one, being connected to the debugging plug is going to implement the first new functions and will later make the old transputer superfluous. On 5/25/2010 the second module in the new setup holding a memory expansion, giving the PEC an additional 24k words of memory ran for the first time. Since the PEC is an asynchronous machine, it is able to run at nearly twice the speed from silicon memory than from its internal core. But due to thermal issues I artificially slowed silicon memory's speed down. Up to now the software on the Transputers is strictly single-tasking, but for the ongoing project (experimental PPT and TTY emulation) it has to go multi-tasking...

3. What are the roots of the unit / architecture...

Talking to experts involved with the computer company Elliott (later GEC-Marconi, Marconi Avionics
and today Selex SAS), based in the UK, it was possible to identify the box by comparison of the command set:
The "Programmer Electronic Control" similar to the 12/12 from Elliott.
This is a downsized 12-bit variant of the bigger 18-bit machines of the Elliott 900
series, delivered beginning in 1965. For information on these (e.g. the 920), look at the
"Our Computer Heritage" project of the Computer Conservation Society documenting
British computers.

The following documents have been carefully preserved for over 30 years by
Terry Froggatt and I am really happy that he shared them with me: The PEC's cousin,
the Elliott 12-12 computer, was used in various applications starting in the
1970ties and some may still be online today! One example of it's use is the auto-
throttle computer of the Boeing 747-100. Look at the flyer and the specification
of the Elliott 12-12 from around 1973:

12-12-Specification

The 12-12 essentially is a repacked version of the deskside Elliott 902,
which was optimized for size, power consumption and the other needs of
airborne computing. Following are a picture and the detailed command
description of the "full size" Elliott 902:

902 Facts Card

The following pictures show the current (6/2008) setup of the Programmer
Electronic Control on my bench with and without explanations. In the last
picture you can see an original paper tape (dated 1/10/1970) sitting on
a PCB of the PEC. I got this from Terry Froggatt, too and it contains the ORIGINAL
assembler for the Elliott 902 called SAP or "Symbolic Assembler Program".

with explanations with explanations IRQ bridged

The next milestones in my hobby are to build blinkenlights for the Programmer Electronic Control,
paper tape and teletype simulations and to execute this software.

4. Suspected original use of the unit...

Avionics specialists suspect that the Programmer Electronic Control was part of the
first models of Tornado ADV's Foxhunter AI24 radar set. According to the timeline, the PEC
might have been used in Stage1 and before and thus probably was retired in 1991.

There must have been "core store loaders" for in field programming of the units
and "operator data panels" (blinkenlights) for service. But my fear is, that documentation
and all other arefacts are long gone...

Any information, hardware, hints, pictures and discussion is absolutely welcome,
please contact me at erik@baigar.de.

5. Emulator for the "big brother" of the PEC...

Software development for the 12-bit Elliott machines was often done on the bigger
18-bit machines (903, 920,...). For these Elliott 900 series of computers there
is a fascinating emulator initially written in 1983 by Terry Froggatt to run on VAX and
later on DOS using Meridian Ada. Afterwards it has been slightly modified and improved by
Don Hunter, who fixed a bug and added support for the plotter and many examples for
the included Elliott Algol compiler. The DOS version (with and without plotter
support, source, manuals and with LOTs of examples) can be found on Don Hunter's page
as a zip-file.

Since I wanted to learn more on Ada, the Elliott 900 and since I love my SGI/IRIX boxes, I recently
ported this great emulator to gnat using GtkAda for the plotter emulation. This one runs on UNIX
operating systems and on Windows 2000/XP. The windows binary including the Apollo8 example can be
downloaded from here (for a UNIX version, please contact me via email):
Windows binary distribution, 1M3, Win32:

Starting the emualtor, the mission of Apollo8 around the moon is simulated: You will observe a
disaster happening at the end. This is due to a wrong staring height in the simulated mission.
If you change the 305km in the last line of ElliottIn.dat back to the correct 300km, everything
goes smooth again...

For many more examples and the original emulator, please visit Don Hunter's page and keep in mind,
that the Sim900al-NT runs many times faster on a decent PC or SparcBook than on the Elliott903!!
By the way: The Apollo8 code you are executing in the emulator must be from around 1964, the "stone
age" of computer technology...

6. External information...

...For more detailed information, please look at the following threads on the usenet or follow the links given:

A condensed report of the reverse-engineering project describing the progress from 1/2005 until 3/2007 can be seen in the cctech archive of March 2007: CCTECH-Report (3/2007). This was the first official status report of the project. Since 8/2007 there is a Extended report in pdf format available, too.
My command reference of the "Programmer Electronic Control" as I decyphered and named the commands. This contains lots of technical information, timings, pinouts and much more.
The "Our Computer Heritage" project of the Computer Conservation Society documenting British computers contains some interesting information (look at E5, the Elliott 900 series) on the bigger 18-bit Elliotts related to my unit in their results page.
Time-line of Elliott/GEC/Marconi's different Systems developed and sold.
Jim Austin has some nice pictures and two comments on his Computer Collection home-page. These show the Elliott903 which is entirely based on Ge transistors.
In the interesting German WWW based FlugzeugForum some relevant discussion happened following a posting in august 2007 reporting on the Programmer Electronic Control (pdf file).
Small thread, similar to the German one above, happened on PPRuNe beginning 15th of August (pdf file).
From the excellent Tornado-page maintained by Chris Corkish I learned many things about the Tornado aircraft.
rec.aviation.military: "Tornado Computer Unit - Any info around?". This early usenet thread from 2005 describes in about 80 postings the early phase of investigation. I even got some input via this thread (pdf file).
Very early thread from February 2005 on PPRuNe asking for any information of purpose, task and origin of the Programmer Electronic Control (pdf file).
de.alt.folklore.computer: "Minicomputer, Minicomputerszene, reine Utopie?", postings by Erik Baigar. In German language, sorry.
Terry Froggatt has valuable information on his WEB-Page as well as Don Hunter.

And some related information/threads:

comp.sys.transputer: "Compile issue with perihelion's cc...". At the very beginning I had problems in compiling my debugging software on the T805 debugging board. Now they are solved and I use a PowerXplorer for development and run the software on the smaller PCB.
comp.sys.transputer: "How to detect Memory-Refresh cycle on T805?". The input helped in solving the core memory access problems of my external transputer based debugging system.
comp.sys.transputer: "FYI: Failure of transputer board VEL/TRP01.A..." incredible but true - I discovered a mounting bug in the small transputer board I use. On a certain qunatity of these vintage boards coming from a large Parsytec parallel computer installation, a tantalum capacitor was soldered in the wrong orientation leading to intermittent problems.
de.alt.folklore.computer: "S: Floppy-Controller WD37C65C". Here I tried to find a replacement FDC controller for the logic analyzer used. But after changing this and doing some investigation I recognized, that it must be a problem with the exotic floppy drive of the HP1661A. So I stopped bothering with this and connected all instruments via GPIB to the SunSparc 20.
comp.sys.sun.admin: "Problem with serial ports on SS20, Solaris 2.6" I tried to fix problems I had with the serial ports on my hardware controlling Sun sparc 20. But somehow they seem to be related to a weired Solaris installation. But since I switched to GPIB this lost relevance.

7. MANY THANKS...

...to the people who contributed by answering to my questions in the above mentioned threads, by supplying information or just by listening or being interested in this project! But the journey is not yet finished, thus:

Does any one know about the origin / original purpose of these units???

Wanted: Information & Artifacts: "Core Store Loader", "Operator Data Panel",...

Any input and every small piece of information is highly welcome. Please contact me at erik@baigar.de

8. Various pictures related to the "Programmer Electronic Control"
and their reverse-engineering (chronological, click to enlarge):

p8172677.jpg 37282 bytes 400 x 300	TypePlate.jpg 107919 bytes 644 x 501	Sticker1.jpg 41609 bytes 533 x 378
Sticker2.jpg 72754 bytes 642 x 452	Connectors.jpg 123828 bytes 682 x 511	ModuleRack.JPG 212096 bytes 1280 x 960
Modules.JPG 167486 bytes 1280 x 960	BoxBottomWithOutSupply.jpg 113159 bytes 802 x 602	CorePlaneLeft.jpg 232751 bytes 1026 x 678
CorePlaneRight.jpg 231696 bytes 1079 x 687	DiodeArraysAndCore.jpg 133177 bytes 807 x 627	MemDriverBrd.JPG 260218 bytes 1280 x 960
CoreMemoryEarlyDoku.jpg 358936 bytes 1037 x 1500	ProcessorTiming.JPG 301171 bytes 1280 x 960	PowerSuppSubAssy1.jpg 83507 bytes 642 x 482
PowerSuppSubAssy2.jpg 85468 bytes 642 x 482	SupplyBackplane.jpg 49321 bytes 642 x 482	SupplyWithSubAssembly.jpg 83372 bytes 802 x 602
Screws.jpg 41871 bytes 643 x 640	Switches.jpg 74399 bytes 501 x 420	DeviceUnderTest.jpg 77114 bytes 640 x 480
CoreMemory.jpg 608548 bytes 1614 x 2146	PROMsFunctionDecode.jpg 170548 bytes 1015 x 753	TornadoLanding.jpg 42483 bytes 980 x 705
TornadoComputerUnitSK10.gif 30570 bytes 1227 x 863	TrapuInterface.jpg 167871 bytes 803 x 648	CoreConnectConsole.jpg 139067 bytes 755 x 480
Connection.jpg 106177 bytes 642 x 482	T805RefreshProblem.jpg 50354 bytes 672 x 400	RefreshDetect.jpg 98007 bytes 641 x 409
T805RefreshProblemSolved.jpg 52654 bytes 672 x 400	T805refreshOK.jpg 196688 bytes 1023 x 495	ConsoleLCDonDPL03.jpg 89678 bytes 754 x 888
Ferrit.jpg 50617 bytes 525 x 424	PEC_SingleWrite.jpg 200612 bytes 933 x 616	PanLink1.gif 7004 bytes 672 x 400
PanLink2.gif 9638 bytes 672 x 400	SetUpPanorama.jpg 762277 bytes 4000 x 2011	SetUpPanoramaExplained.jpg 131794 bytes 1280 x 644
920B_Function12_AP112H-0301.gif 715975 bytes 2391 x 1565	_SecondUnit.jpg 72891 bytes 750 x 951	_SecondUnitTypePlate.jpg 139685 bytes 1101 x 785
_View1.jpg 83963 bytes 707 x 764	_View2.jpg 141305 bytes 1053 x 818	_View3.jpg 153753 bytes 1070 x 830
_SecondUnitUnpacked.jpg 116429 bytes 745 x 819	_BackplaneView.jpg 39464 bytes 424 x 439	_CageEmpty.jpg 188995 bytes 1028 x 935
_ConditioningLabel.jpg 77811 bytes 768 x 1024	_CoolantConnector.jpg 55640 bytes 949 x 947	_DifferenceBetweenUnits.jpg 85220 bytes 677 x 717
_ModulesPulled.jpg 161397 bytes 1280 x 960	PEC_TrapuIO20081022.JPG 191083 bytes 1024 x 677	CPLD-EvalPCBonPEC.jpg 395451 bytes 1159 x 1192
Rotary100Winverter.jpg 156666 bytes 1280 x 875	PECversuchInverter20090214a.JPG 356318 bytes 2024 x 955	SolderedPinsPain.jpg 113980 bytes 891 x 897
InsertionRemovalTools-20090306.jpg 127217 bytes 800 x 523	DMCcrimper20090311a.jpg 58218 bytes 640 x 493	EmptyPCBs.jpg 171733 bytes 1280 x 899
FastLink-PCB.jpg 128303 bytes 800 x 600	FastLinkPCB-20090311.jpg 99139 bytes 720 x 550	TrapuLinkPCB-20090310.jpg 125126 bytes 800 x 600
DPL07experiment.jpg 140999 bytes 800 x 706	PlotterSetup.jpg 98629 bytes 819 x 1024	PlotterPECTOS.jpg 80191 bytes 1036 x 656
PlotterOutput.jpg 125914 bytes 1152 x 920	Plotter-HPGL.jpg 58750 bytes 838 x 629	DPL07-Cable-1.jpg 195642 bytes 1024 x 512
DPL07-Cable-2.jpg 129247 bytes 800 x 600	DPL07-Cable-3.jpg 239522 bytes 800 x 943	Facit-N4000-PaperTape.jpg 141239 bytes 640 x 1110
Elliott-SAP.jpg 119303 bytes 1024 x 553	WaveformGenerator-51-011-21.jpg 200856 bytes 1024 x 1313	WaveformGenerator-51-011-21-TypePlate.jpg 95492 bytes 800 x 457
PEC-LED-Line.jpg 330009 bytes 1280 x 960	PEC-LED-Line-Jig.jpg 217426 bytes 1024 x 749	DataMonitoringUnit-Parts.jpg 143448 bytes 800 x 569
3phaseInverter-2010326.jpg 111790 bytes	3phaseInverter-2010325.jpg 150920 bytes	Elliott905-Bletchley.jpg 105703 bytes
TSR2-Cosford.jpg 139247 bytes	PEC-SetupExplained-20100518.jpg 734835 bytes

9. Older history:

6.7.2009: Checked all pages for dead links and removed them; added diary to the "PEC-page.
6.6.2009: Added pictures of latest milestones - plotter is running under control of PEC now.
Pictures sorted chronologically. Added index.
31.3.2009: Added counter and some explanations to the documents from Terry Froggatt.
8.6.2008: Added technical information on all chips, used on the unit together
with date code statistics. Added picture of 902, too.
4.5.2008: Added NSNs, Part-numbers and pdf with pictures of all PCBs.
29.4.2008: Added Elliott 900 series emulator (Thanks to Terry Froggatt & Don Hunter).
28.4.2008: News: The unit is said to be part of the early Foxhunter Ai24 radar
of the Tornado ADV aircraft.
28.2.2008: Added some links (picture 903, time-line).
19.1.2008: Added pdf containing all secrets I prayed out of the box,
box identified as an Elliott 12/12. Probably NOT from Tornado.
5.1.2008: Added pdf files of the relevant threads in newsgroups etc.
7.11.2007: Update with new pictures (Starting with _), including new unit.
15.9.2007: Got second of the units, serial number 129. Both units show same
behavior in all respects. New unit has maintenance sheet attached,
thus assumption is: Both units are OK. ;-)
17.6.2008: Now ALL (even the custom ones) chips in the PEC are identified, thus there
is an updated version of the Reference-Page with pin-outs.
15.6.2008: Added additional Foxhunter picture, both now available in better
resolution. Uploaded new documents about 12/12 and 902 but not
properly included yet - sorry.

Generated with help of HTMLThumbnail 1.1.4 by Erik Baigar on SGI/I2, 15/06/2008, viewed times. Impressum: HIER.