Toastie

Dear All, motivated by Evan’s 9750 EuroBricks hacking challenge, I tried to get my beloved Amstrad PCW 8512 (named by Amstrad's CEO Alan Sugar “Joyce”, which is the given name of his assistant) along with an SCA Systems parallel/serial interface in touch with the LEGO Interface A (#9750). It appears as if TLG never wondered into Amstrad world; they were more on the professional IBM, Apple, Acorn, Commodore, and Philips side of things. Expensive things that is; not on the el cheapo side, were I was. Here is the video proof that it works ;) I did not upload that video to YT - it is too crappy https://bricksafe.com/files/Toastie/amstrad-8512-and-9750/Amstrad 8512 LEGO 9750.mp4 To begin with: Here is my vintage compuing corner in the attic (this room also serves as my home-office) - along with the vintage LEGO stuff, which is controlled by these machines: (1) is the PBrick section (RCX, Scout, IR serial and USB tower, Sybotics with optical serial connection; the Vision Command camera setup is controlled by the Scout; Cybermaster with the RF tower below. The barely visible TC brick sorter robot is controlled by the RCX. (2) is the LEGO interface A (#9750) section; there is a 4-way switch that allows to use multiple computers for the interface: The IBM XT (A), the Toshiba Satellite 4090 (B), which is on a pull-out shelf, or any modern computer via an Arduino USB28bit parallel interface mounted right to the interface A. The 4.5V motors of the TC robot (3) below are hooked up to the Interface A; additionally, a PUp tacho motor and a Technic hub control the lateral movement - synching and programming reported here on EB. (4) is a second Interface A - this again is on a 4-way switch (located above the (D)) to be controlled either by the Amstrad PCW 8512 (C) or the ZX81 or ZX Spectrum (D) or the Atari 1040 ST or the C64 (E). The second Interface A is intended for testing and trying out things; there are 8x 4.5V lamps and 2x 4.5 motors with 2x light sensors on a 32x32 base plate. Both, the interface as well as the Atari and C64 are on pull-out shelves. So without further ado: Here we go again ... and yes, my posts in this regard may be annoying, but so are super cars. Or Cada stuff, 2++ m tall cranes, ++$600 sets – >only< to me, that is! And here is to feeling good! The Joyce [(C) in the above photograph] is one of a kind, I can tell … its design is beyond belief – in the absolutely positive sense. Made for the masses, using incredible techniques. IBM just went ballistic with regard to parts and pieces in their original PCs and then XTs (which I am madly in love with). 8000 something German Mark in 1983. And TLG was sailing along – after three more years they introduced Technic Control, and PC’s, XT’s, Apples, and so on were the prime machines targeted for that technology – in schools that is … no way to go cheap there! Now, the PCW (Personal Computer Word-processor) 8512 was not as cheap as Sinclair’s ZX computers; it cost about one quarter of what IBM charged for their PC. But: It was a fully blown word and database processing system. No built-in graphical stuff, just pure text and number crunching. The OS was CP/M 3.0 (“CP/M Plus”) – which was “the basis” of (or better copied by) Microsoft’s early versions of MSDOS. CP/M is so cool … and of course programming languages also work on the Joyce; as I wrote many times, I am a total BASIC person. Joyce came bundled with the “LocoScript” word processor and with “Mallard BASIC” for CP/M Plus, both made by Locomotive Software in the early 1980’s. The following citation is what I really like about the name of that BASIC dialect (copied from the referenced Wikipedia article): “It was also optimised for speed — it is named after the LNER Class A4 4468 Mallard locomotive, the fastest steam locomotive in the world, once again displaying the company's fondness for railway-oriented nomenclature. In fact, the Locomotive Software name came from the phrase "to run like a train" and it was this theme that was used to name Mallard BASIC — no other Locomotive Software product was named after anything railway-oriented.” And behold, Mallard BASIC is fast! Joyce came also bundled with a 9-needle dot-matrix printer, which mechanically attached seamlessly to the keyboard mimicking a type writer; there are recesses for 2 brackets in both devices. I believe though, virtually >no one< actually used that feature, as it consumes considerable space in front of the screen. Joyce’s brain is a Z80A CPU – my all-time favorite microprocessor. Why? Because back in the 1980’s, I must have referenced the German edition of Rodnay Zack’s book “Programming the Z80” a thousand times as I was fascinated by the performance boost when programming in Z80 assembly code, as compared to e.g. BASIC. All my computers I had back then (and still have today) had Z80 CPUs: Sinclair’s ZX81 and ZX Spectrum, and Amstrad’s PCW 8512 “Joyce”. On the Joyce, almost all Z80 CPU signals are exposed on the back connector along with some other lines. But there is more (there always is): Joyce features a printer port, which is (exclusively) connecting with the Amstrad/Joyce 9-needle dot matrix printer. One can of course connect custom devices to that port, but that needs intimate knowledge of the innards of the hardware. Which is not that straight forward, as Joyce features some rather powerful chips, among them an 80 pin flat pack gate array which does a lot of housekeeping tasks, the well-known NEC µPD765AC-2 floppy disc controller, and even a second microcontroller, the NEC µPD8041AH, which is a programmable peripheral interface controller. The latter features an 8bit CPU, 1kbyte ROM, 64 byte RAM, 8bit timer/counter, and 18 I/O lines, which all go to the 9-needle dot matrix printer! Nothing really easy to hack for the interfacing of Joyce with LEGO interface A, particularly with access from BASIC. Mallard BASIC does provide the command “OUT address, data byte” and the “INP(address)” function for direct Z80 I/O port access, but I would not know how to dig through the PPI controller to read and write to #9750 through the built-in printer port. Fortunately, I got hold of the SCA Systems serial/parallel extension interface for the Joyce. There are at least four such interfaces from different vendors I am aware of. Two of these are the Amstrad CPS 8256 and the SCA Systems interface. At first glance, both their PCBs look identical, but closer inspection revealed that there are differences, particularly in the address decoding section. The circuit diagram and photographs for the CPS 8256 are available on the internet, similar stuff for the SCA interface is not, as far as I know. So I had to do some PCB track tracing, at least for the address decoding. After a lot of beeping through the tracks, I came up with the partial circuit diagram below. I was very happy to learn that the TTL 74LS373 chip (8 transparent D-flip flop latches, as TLG used in their #9771 ISA card for IBM PCs) directly connected to the 8 data out lines of the Centronics port of the SCA interface! From there it went straight downhill. Above: Circuit diagram of the address decoding section and the 8-bit 74LS373 output latch interfacing to #9750. The blue box contains my additions, i.e., a second 74LS373 and a 4x NOR gate 74LS02 TTL chip. Address decoding and data read/write procedure I wanted this interface to act in exactly the same way as TLGs #9771 card behaves: Upon emitting 1) the correct address, 2) the 6 data bits for the 6 output channels of the interface A, 3) IORQ# (# = active low), and finally 4) WR#, the C line of the “output 74LS373” goes H and thus it mirrors the content on the 6 D lines connected directly to the Z80 data bus transparently to the corresponding 6 Q outputs. As there is no change on the data bus as long as WR# = L, all emitted data are securely latched, when WR# goes H again (i.e., the C input of 74LS373 goes L). No more changes of the output lines are possible until the next complete write cycle. OC# is connected to GND and thus the chip has always activated outputs, see below. Well, this is how it is done on the #9771 card. But to my surprise, I did not find any WR# line connecting to the address decoder, I found only address lines and IORQ#. At first, I was puzzled but then realized: The 74LS373 in the SCA interface is for writing only. No data are read from the 8 Centronics data lines; the two Centronics flow control lines BUSY and STROBE# are routed to the Z80DART in the SCA interface. In other words, no WR# decoding is necessary in this scenario. SCA used the 3-to-8 demultiplexer 74LS138 for Centronics port address decoding in the following manner: The output Q7# of 74LS138 goes L (= is selected) when its data input lines A(=A3), B(=A5), and C(=A6) are all H, the enable line FE1(=A7) = H, and the enable lines FE2A#(=IORQ) and FE2B#(=A4) = L. In all other cases Q7# = H. This signal needs to be inverted, and SCA used the second 2-to-4 demultiplexer in the 74LS139 TTL chip to do just that: When Q7#(74LS373) = L, Q2#(74LS139) = H. The decoded Centronics port write address is thus: A7 A6 A5 A4 A3 A2 A1 A0 H H H L H X X X ; = 0xE8 to 0xEF, as A0 – A2 are not decoded The Q2# line of 74LS139 used as simple inverter is routed to the C input of the 74LS373 8-bit latch: When the address is within 0xE8 to 0xEF, the data bus content is latched upon IORQ# = L. However: This approach does work with a Centronics printer but not for bidirectional operation of LEGO interface A: Using TLG’s TC Logo and other programming languages, you can write to the 6 outputs and read back the status of the outputs as well as the status of the two sensor inputs of #9750 at the same address. So this calls for a (very) little tinkering with the SCA circuit board and the addition of a second 74LS373 (read latch) and a 4x NOR gate 74LS02 TTL chip, see circuit diagram above. In addition, pin 6 of 74LS139 in the SCA interface needs to be bent up – there is no use for this inverter after pimping the board. Next the WR# and RD# lines (connectors 39 and 41 on the Joyce expansion port) are wired to the inputs of two NOR gates; Q7# is wired to both other inputs: When WR# and Q7# = L, the NOR gate for reading = H; when RD# and Q7# = L, the NOR gate for writing = H. The latter means that this signal can be directly connected to the C input of the 74LS373 latch for storing write data. For reading back all 8 bits with the additional 74LS373, the corresponding NOR gate output signal needs to be inverted: This signal goes to both, the C input as well as the OC# chip enable input. When OC# = L; the chip is enabled; when it is H, the outputs are in “tristate”, i.e. not visible on the data bus. All inputs remain active though. When C and OC# = H (wrong address, IORQ# is not = L, RD# is not = L) the outputs of the second 74LS373 are in tristate but the D-inputs follow (transparently) the data bus content. When C and OC# = L, data on the D inputs are immediately latched (no more changes recognized) and the outputs are activated, mirroring the D lines content very shortly before C became L for the time of the RD# signal = L (i.e., the Z80 CPU fetches the data bus content). The moment RD# goes back to H (= data are in the corresponding register of the Z80 CPU), the second 74LS373 goes again into tristate. This is in principle how it is done on the IBM XT #9771 ISA card as well. I also used a similar approach for my ZX81 and ZX Spectrum interface for #9750. It is a bit different on my Atari 1040 ST, as the printer port is handled differently on these machines. Here are some pictures of hacking the SCA Systems interface for operating LEGO Interface A with an Amstrad PCW 8512: Left: I had to cut into the SCA interface enclosure to access the built-in 74LS373 - this "channels" all 8 data bus lines as well as +5V and GND to the outside. Also the 6 Q outputs going to #9750 are available. Right: I simply soldered two 1x10 Dupont type connectors to the solder pads of the 74LS373. The wires seen are RD# and WR# from the control bus, Q7# and the new line replacing the Q2# line going to the C input of 74LS373. Left: The TTL chip on the lower right is the 74LS373 output latch I am tapping into (or better onto ;) Right: The add-on board attached to the RCA interface; the front connectors are compatible with the orginal LEGO 20 ribbon wire for the Interface A. As always: Tried to match an enclosure - the golden 1x6 tile is from the stand of my MK Flying Dutchman. 3 windshields make the side walls. Left port: Centronics - still works. Right port: RS232 - still works. Top port: LEGO Interface A - works. And finally, we can add another computer system from the 1980’s, which was not endorsed by TLG, to @evank #9750 challenge list. The chippies used are all from way before 1990. I feel good . All the best, Thorsten

@cbqmp27 I don't have any experience with PyBricks and @Lok24 will know much better! I am just wondering: Do you have to tell some code lines, which motor you have attached? I guess not, as the hub figures that out (at least when running on the LEGO firmware). Also, the LEGO PUp L-motor is a tacho motor - it has a built-in rotation sensor you can use for different tasks and purposes, among which is "SetSpeed" rather than "SetPower". This is particularly interesting for the Crocodile. Using the SetSpeed command makes it run with - well constant speed. The firmware adjusts swiftly the power setting when speed is not as wanted. But again this is all pure speculation. Best, Thorsten

That is what I thought! My all-time favorite PBrick. Now, the RCX running LEGO firmware is not that fast to do PID calculations - it has to do that since that firmware had no built-it PID routines. I guess it runs on another firmware. The RobotC firmware (Dick Swan) was pretty fast - I did implement PID train motor control back in the days. And there are other programming languages as well. However, I cannot discern any rotation sensor. Without - no PID control. I also believe that the 9V Technic motors are in favor of using higher rpm's. Best, Thorsten

@Peppermint_M Thank you very much for that post. I believe this really makes a difference - knowing where it came from and what the initial impetus was, puts many things into perspective. I really enjoyed reading about the history of EB! All the best, Thorsten

Well, may the 1st be with you Day off here too, but wife called for major living room renovations, which started 3 weeks ago ... almost done though. May 1st came in handy for some cleaning frenzy. Anyway: Very nice and really impressive (!) work on reverse engineering that set. It sure needs a >lot< of Technic experience, visual interpretation skills, and then virtual construction. All the best, Thorsten

Oh, I really wish I could help out - but no interface B here, nor Robolab 2.5.4. Hope that someone can help out here on your issues! Good luck and best wishes, Thorsten

100% my take. I am nowhere but YT (videos) and EB - and for picture and "stuff" storage on Brickset. I like to add that we have >educated< discussions here on EB. This forum is as well a repository for so many LEGO related things, from today to going way back. The search function on EB usually results in a mess of hits, but Google has it very well indexed. Nice to read that there are some folks not going nuts on "social media" when it comes to LEGO. There is nothing wrong with sharing ideas, projects and results on these platforms (!), nothing at all! But for me, it is EB. Best, Thorsten

It really is, nice find! However I believe the authors are slightly off with regard to the beginning of LEGO robotics. They write that in the late 1980's it all began with the Interface B using serial communication. I may be wrong (and @evank as well as @alexGS and some others will know better), but I believe it was the LEGO Interface A using parallel communication on a number of computers via their built-in ports (e.g., C64) or LEGO interface cards (Apple, IBM), which started it all. Around 1986. The Interface A directly (more or less ) listened and talked to the data bus of the computer. Evan has composed an introduction to LEGO robotics on his website, which nicely covers the very early days: https://www.brickhacks.com/0.php Thanks for sharing!!! Best, Thorsten

Oh yes, that is true. The whole CM environment is so cool. I have the original software (not) running (on Win11 but) on my Toshiba Satellite 4090, and I really admire the work they put into that true adventure. CM was before RCX, and it was much more play-oriented than programming. More or less the same approach TLG tried (again, but in reverse order) with the introduction of the Scout PBrick after the RCX. Both, the CM and the Scout have rather limited memory space of accommodating about 400 LEGO byte codes - but you can do a lot(!) with that, because you can tap into the countless built-in routines for sound, light and whatnot. I really like this approach: CM and Scout for having fun, RCX for heavy lifting - I have no idea, though, how many lifts were done ... But you need to fire up your CM bricks again - even the moment it recognizes the tower = computer is a blast. Best, Thorsten

Hi Lars, no, unfortunately, I don't. It is one of the "last" ;) vintage items, I really like to acquire. So, on your side, does interacting of Robolab with the RCX work? And if so, how? Do you use the serial or the USB tower? Best, Thorsten

@Carsten Svendsen oh, I can see that so clearly; the Cybermaster PBrick, even without all the bricks and builds, is a true blast! And Technic Gold. I never had any Cybermaster sets back then, but recently got hold of a couple of CM PBricks and RF towers; they sell for next to nothing on BL, which I do not understand. Well, actually I speculate that these $5 prices are caused by the often faulty motors, where the disk magnets inside were corroding; the same issue some 9V Technic motors had, even with Chromium plated magnet surfaces. I bought about 8 CM units and could assemble two fully working PBricks. Changing the motors is, due to the wonderfully designed circuit board, really easy. And on each faulty unit, you still have the third motor output (9V 2x2) working! Now, with regard to VMs, serial ports, and so on: If you want to program these beauties, just install the BricxCC suite on any modern (Win11, 64 bit - works) computer, get an USB2Serial adapter, plug that in, run device manager, find the COM port number of that adapter, edit the address to < COM 8 (if necessary, simply move anything modern occupying the low COM port address space to port numbers > 8), run BricxCC, choose CM, choose the COM port of your adapter and then program, remotely control, monitor ... your CM PBrick. It is really cool - and does not need any line of sight. I have so much fun with these! All the best, Thorsten

Hi Lars, unfortunately, I don't have Robolab. However, Google tells me that it was intended to be used for programming the RCX and the NXT. The RCX uses either the serial or the USB tower, the NXT a USB cable or Bluetooth. As per Google, Robolab 2.9 does not support BT - that leaves you with the UBS cable for the NXT; I would not know how to attach the NXT via a serial cable. The only "RS232" only device in your list is then the interface B, correct? That works with a USB2Serial adapter, right? Or is your inquiry software related? As in: "Does Robolab 2.9 support direct RS232 communication?" I am a bit lost here. I'd just use the USB ports on the XP machine with USB2Serial adapters where required (i.e. for the interface B). Best, Thorsten EDIT: I just found Robolab on the InternetArchive, installed it and ran it on my Win11 64 bit laptop without problems. As it shows the RCX, NXT, and interface B on the "RCX/NXT settings" tab, and you can select the COM port you want to use along with each of those, I guess all should be fine with USB2Serial adapters, right?

No 9V motor though, no LED lights, no PF control, no proper wiring, no stickers, just the barebone loco (for € 36.95,- + shipping) And for sure, no concrete slabs on no concrete slabs wagons! These are really cool. Congratulations again, Emanuele, and again well deserved! I'd love to see some pictures of your soldering - I don't know anyone who does that that accurately. How do you turn on the lights? By switch or per PF remote? All the best, Thorsten

Hi Emanuele, very nice indeed! Very accurate and with much attention to detail. As always, that is ... and congratulations to decorating the front page, this is well deserved! All the best, Thorsten

When I need a piece/part TLG will never make (tailored electrical feedthroughs, LEGO enclosures for custom PCBs, and so on and so forth) I do cut, glue to make it fit. It is solely for my very own purpose - TLG's sold parts count on these is exactly >one<, and I believe a mold for producing that piece a a little over the top. Other than that: I go with the flow, as they say. Regards, Thorsten

Same here. Hmmm - is this what a large company does, when it runs out of good ideas for new products based on (way more than) half a century old principles? Do they make a new typeface based on their product? Or actions symbols. Or motion symbols ... in the end, the world will be rebuilt - using LEGO bricks. I am missing brick built symbols for feelings ... for starters, TLG could use #3176 or #39613 for true love ... would be a one-piece, no building necessary, hit-home symbol. No idea what's going on ... just guessing. Best, Thorsten

Thank you very much, Thomas! As said, you and Steffen made this happen. No joke or whatever. Well, I felt I have to. This is more than 90% of non-tolerated alternative brick usage - some call unilaterally "knock-offs" here on EB, regardless of actual source and source ethics - so I decided to show it here and then brag about it. The "12V monorail" is presented in the TrainTech forum, because that is made of 100% LEGO pieces. The wonderful train though - that TLG will never ever be capable of making nor wanting to make at any reasonable price - is inappropriate to show there. And so - I am here. And I am very glad you found this post and commented, as I admire your work very, very much! Thanks again and all the best, Thorsten

Well, inside the EU similar "things" (not exactly, as there are competing companies) apply. For sure, they will be totally complex and there are gazillions of rules and regulations. EU ^^, what do you expect. However, shipping is generally >much< cheaper within the EU than to GB. Brexit is Brexit, I guess. Best, Thorsten

Sure, that will work! BUT: Why not installing the full TLG EV3 software suite and have fun??? Just because some newbies or whatever that generation is called, call it old, outdated, whatever? These folks have certainly missed out I am a true boomer - and for me, an EV3 is a performance monster, hardly being challenged by many to the extent that it chokes or fails. There are some here on EB and maybe elsewhere (I am not elsewhere, so correct me if I am wrong) who came to that barrier, but mostly it is: "There is more. There is always more." as in PUp, Spike and Prime. Who cares? Do your EV3 experience. Enjoy it. Just get out the original software - it installs on modern computer hardware. Then play around. Once you feel that what TLG has provided is not enough - dive into alternatives, like pybricks. Make sure you have ideas for what you want to do with the EV3 power brick first. Then go nuts. Have fun and all the best, Thorsten

Hmmm - the question is: What is going on in the old tower? Memories come to life: Back in the days I spent some 8 weeks in Christchurch College in Oxford/GB to do some research in the physical chemistry lab. And my goodness, this college had some nice grass tennis courts!!! OK, back on track: Next to the entry doors to the old college was/is Tom Tower - and you simply don't want to know what a nice (party) place that was/is - back then in 1990 that is ;) Heehee - OK: You go down the road, into the beer store, stock up on beer and such, then just move on, stock up on - no, wait. Not smart: You gown the road, stock up on Tylenol, Aspirin, and this and that, and have still both hands free for getting some beer next door. Perfect! Now: What is going on in the tower??? Lovely building, very nice building techniques and: Thank you very, very much for sharing the instructions!!! Regards, Thorsten

The joke is not the text nor the picture, this is so 50's, it is the title. Finally, truth has come: It is "Legos" (ssss). Y'all were wrong. Happy Easter. Here is to feeling good

Yes: To get to the metal, the greasy stuff needs to go first. IPA is for that job; otherwise, the much more polar metal oxide removing ingredients can't do their job, as grease would not let them penetrate to the "problem". When you have cleaned the rails with good soap, a wash/rub with IPA is surely helping in removing remains of grease and such. I generally use this stuff for work on vintage plastic material as a first step; there is not a bit of non-polar stuff remaining on the surfaces. Also, your fingers/hands will be totally degreased , so it is better to wear some (cheap) gloves. Best, Thorsten

Very nice that this worked out. Now, I have said that here and there on EB - and I don't want to be regarded as wise-***. However, this may actually do a better job conduction-wise, than ethanol or IPA can do: They both remove greasy stuff, as does soap in any incarnation. There are differences; when you apply "plastic cleaner detergent" they will perform more powerful. In removing anything greasy. Conduction-wise, you want to get rid of oxides, sitting on the metal rail, that don't care about any kind of soap at all. Sure, removing greasy stuff will help. And if that is the sole layer affecting any conduction issues: Job done. Now, if there is more (there is always more ), then try metal oxide removal agents. WD40 is such a formulation, but it bites into the plastic as well, plus it adds residue, you simply don't want to have. There are many formulations used in electronics for doing just that: Remove oxide layers from metal, be it copper, or in case of 9V rails, nickel (alloys). One product that I use quite successfully, not only on 9V rails, but many vintage electronics projects is "Kontakt-60" spray. I am sure, there are many other products doing the exact same. Just to give you a hint (and yes, I am not affiliated with this company, not at all): https://www.reichelt.de/de/en/contact-60-100-ml-oxide-removing-contact-cleaner-kontakt-2010-p9462.html?PROVID=2788&amp;gad_source=1&amp;gclid=Cj0KCQjwzZmwBhD8ARIsAH4v1gU4Xb17IYrV9eIIqsGUDuvtqJf5gShwveDUt3liQWwnMU7YFokCOEMaAi8BEALw_wcB&amp;&amp;r=1 It simply works. All the best, Thorsten

Hehe ... the "th" - simply forget it: Try "Torsten". The "h" apparently comes from "Thor" - the vikings loved to give their names an edge ;) and the "sten" apparently comes from "stein" which translates to "rock". So my name refers to Thor's hammer's head, made from rock. Yeah. I run around in this world with a name referring to Thor's hammer. Thank you, my parents . In Northern Europe, "th" translates to "t" in the English language. In other words: >NO< reason to apologize!!! In contrast: I love your smile and laughter in the video - this is how it should be - always. All the best, T_orsten

Welcome to EB! That "whole" refers to the "plastic" of these parts, correct? Best, Thorsten