Toastie

@evank Hi Evan, all, I believe having another entry for the 9750 hacking contest: The Sinclair ZX Spectrum, doing it with a little help of a couple of TTL chips from the late 1970's to mid 1980's. The Spectrum debuted in 1982; I got mine (the one now controlling #9750) in 1985. Should be all within the contest rules: (The 8 4.5V lamps signal a very important message ...) Main post is in the Technic etc. forum, even with a stupid 20s video at the end: Next thing to do is getting my ZX81 and #9750 together. Needs a little hardware tinkering again. Also ZX81 BASIC does not know OUT/IN, only PEEK and POKE, which means I need using the MREQ# Z80 CPU output instead of IORQ# (memory mapped). All the best! Thorsten

Dear All, motivated by Evan's Eurobricks 9750 hacking challenge, I tried to get my beloved ZX Spectrum (Speccy) in touch with the LEGO Interface A (#9750). It appears as if TLG never wondered into Sinclair 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. My Spectrum is an Issue.3 machine from 1983 –Sinclair introduced the legendary ZX Spectrum in 1982 – as successor of their legendary ZX81 from 1981, which was the successor of their legendary ZX80 from, guess when, yeah 1980. And yes, I do like the Sinclair machines very much, as they taught me (a low income chemistry student) how computers work on the hardware level, at the lowest price tag possible (so I could afford these machines) and they taught me how machine language and assembly works. A very nice coincidence regarding LEGO Technic Control and computer hardware for the masses in the 1980’s is shown in the photograph below: The background is a copy of one page of the service manual of the ZX Printer, which came out in 1981. I also had one for printing endless lines of Z80 disassembly code (mostly for cracking the copy protection of video games, see “print” on the right). At the top center there is a Technic 4.5V motor (#6216), a Technic disk with 4/8 black sections (#2958) attached to the hole of an 4.5V light sensor brick (#1161); actually the latter has an IR emitter and IR sensor inside. The Interface A powers and reads these and thus the status of the disk: Black = 1/off, white = 0/on. TCLogo running on a PC samples the >change event< with 1kHz temporal resolution, has two counters, and calculates the frequency of the changes, among other things, and makes them all available to the user. Well written assembly code >is< fast … On the bottom there is the main board of the ZX Printer along with its DC motor – and a disk and the light emitting diode. The disk has transparent and reflective sections (many more as compared to the Technic disk) but the principle of operation is absolutely the same. The Ferranti ULA took care of all the above; the Spectrum (or ZX81) just had to send “make dot”. Here we go: Inside my Speccy, the address lines A5 to A7 and the I/O request (IORQ#) line of the Z80 CPU are already hooked up to provide 8 “chip enable” signals (L=enabled), that I can “freely” use. Due to the “interesting” I/O port address decoding of the Spectrum’s very own hardware (>every< even address activates something in the ULA – Ferranti’s uncommitted logic array chip. It does almost everything other than CPU/memory stuff), care has to be taken upon addressing further I/O ports. Address 1 works, 2 does not, 3 works etc. Sinclair did that for cost saving purposes of course, as the address decoding is kept to the absolute minimum. The Z80 CPU has 16 address lines, which means a lot of decoding to filter out one specific address. Now, other add-on hardware (Sinclair Interfaces 1 and 2, or one of the myriads of third party vendor products, for example) then need to tip-toe between the even addresses – and when they went cheap as well, entire address ranges are blocked as well. Back then (1986 that is) I “blocked” the address range A5 - A7 with all A0 – A4 = 1 (no even addresses!), which gave me 31 (0x1F, bin 1 1111), 0x3F, 0x5F, 0x7F, 0x9F, 0xBF, and 0xFF as I/O port addresses. My ZX Interface 1 does not use these, so they actually work, even today. I used I/O port 1 = 0x1F for 32k bank switching, 0x3F for turning an LED on and off. The latter is the port I am using here to control #9750 as well. The BASIC commands are (as usual …): OUT 63, data (data = 0 to 63 for any of the 6 channel configurations) – this turns also the front panel LED on LET i = IN 63 (which returns the status of the 6 9750 output channels as well as the 2 sensor channels – this also turns the LED off). I simply copied the LEGO #9771 ISA card approach using two 74LS373 transparent D-flip flop latched as described in detail here. This is a rather elegant way of getting instantaneous feedback on the output status using rather cheap, but electrically powerful chips (TTL drivers). I/O address decoding is done in the Spectrum’s gut as shown in lower left blue box in the schematic below, with the 3 “extra” (see below) lines RD#, WR#, CE#: How does it work? When the Z80 writes to an I/O port, it puts the corresponding address on the address bus, pulls IOREQ# low, puts the corresponding data on the data bus and then pulls WR# low. The address is decoded by 74154; the corresponding output (0 – 15) goes low, but only when the chip’s outputs are enabled, which is the case, when EN1# and EN#2 are both low. EN2# is always low as it is tied to GND, EN1# when IOREQ# is low. IC3c (NOR gate) receives the Q1# output signal on one input, WR# on the other. When both are low, C of IC5a goes high and the transparent latches follow the signal at its 8 (6 only used for #9750) D inputs which are connected to the data bus of the Speccy. During this time, the Z80 holds the data from the BASIC "OUT" command static on the data bus. Upon pulling C high again (write cycle is over), IC5b freezes-in the 8 data inputs and clocks them onto the corresponding Q outputs connected to #9750. As OC# is always low, the outputs of IC5a are always enabled. When the Z80 reads from an I/O port, essentially the same things as above happen; now the RD# line is pulled low (somewhat delayed, i.e., closer to the rising edge of IOREQ#), and data are transferred to Z80 the accumulator register. However, the outputs of IC4a, again transparent D latches, are only enabled, when the correct address + IOREQ# + RD# is active, i.e., for a very brief moment. It has to be this way, because the Q outputs of IC4a are connected to the system’s data bus and would crash it at once when RD# goes high again (read cycle done). Most of the time pin C of IC4a is high (in contrast to IC5a, where it is always low = enabled), so the Q outputs are in tristate (high impedance or simply “not there)”, but the D inputs constantly read a) the state of IC5a’s outputs and b) the two sensor lines from 9750, i.e. they are always up to date. Upon a valid read request, pin C of IC4a goes low – at the same time its outputs are enabled: #9750 status freezes-in and is clocked onto the Q outputs = Z80 data bus. I like this approach using the transparent latches very much! This is of course owing to the fact that TLG’s programs (TCLogo and the like) write the “code” 00010101 (0x15) to #9750, then read back the #9750 status (the sensor readings are stripped, as they may have changed in between OUT and IN). The remaining connections required for the interface (data lines D0 – D7, +5V, GND) are obtained from the edge connector of the Spectrum’s PCB. Although I have the corresponding bare plug, I wanted to use the ZX Printer cable and case as interface box, as an homage to Sir Clive Sinclair : For the parallel Atari and the serial PC interface (USB and/or RS232), I made brick-built cases. Initially I tried using an Intel 8255 PIO (https://en.wikipedia.org/wiki/Intel_8255) as communication hub for #9750 (= total overkill, but I had three of the PIOs) – because it is a fun chip, debuting in the mid 1970’s. I guess I got the addressing wrong; a 8255 wants to know, what to do upon powering up, default is all three 8-bit I/O ports = inputs. I could not get the configuration right – I guess the ULA was addressed as well and things totally screwed up. I shall give it a second try “later”. I thus reverted to TLG’s “2x 74LS373” design, and made a perfboard version of the circuit shown in the schematic above, which fits into the ZX Printer case. I used the original printer cable (rewired inside the plug, as the printer uses other signals then #9750, such as address lines) and made no changes to the outer appearance of the printer. There are only 12 wires available; thus the 3 extra wires from the Speccy came in handy as additional inputs to the interface. Absolutely not nice, but: works. I guess a black ribbon cable looks nicer, but right now I don’t have one. Upper two pictures: (Left) Perfboard mounted into the printer case and (right) connector to #9750 and address decoding board. The latter is simply tying together RD#, WR#, and CE# controlling the C and OC# inputs of the two 74LS373. I made this extra board so that a different approach using 74LS374 just requires exchanging them for the 373’s (they have the same pinout), which are clocking in the data upon any rising edge at their CLK input (recall that 373’s freeze in data when C = low and set their outputs accordingly; no edge trigger required, and the Q outputs follow the D inputs when C = high). 374’s thus need a slightly different address decoding using NOR gates – and thus only the additional board needs to be replaced. This board is attached with Dupont type connectors. Upper two pictures: Finished interface without (left) and with (right) metalized paper roll inserted. I need to make a cover for the soldered pins of the 20 pin flat cable connector I desoldered from an old Shimadzu mass spec in the lab; otherwise the paper may cause shorts. Almost forgot: The switch S1 in the schematic above is actually the original paper feed switch of the ZX Printer, located at the top right of the case. Sinclair used this switch upside down: The knob sits in a fitting mount on the bottom of the printer case; a plastic rod extension with a little knob at its upper end is the switch’s actuator – you are pressing the switch body onto its fixed knob – I love it. Simply ingenious. In my setup, the switch pulls the "OC#" line of IC 5a high, and thus turns it's outputs off - should something go wrong on your TC LEGO model and #9750 is not in reach. And finally here is the entire ZX Spectrum + ZX Printer interface + LEGO Interface A – the program running is the old-fashioned TLG version; but this time, the presence of #9750 and the interface is checked by asking for the answer to the ultimate question of life, the universe, and everything, which is 101010 of course: BTW: I think the LEGO Interface A “look” very nicely matches up with the ZX Spectrum and ZX Printer design; too bad TLG did not see that, back in 1986. Sinclair BASIC at its best: The program does this: https://bricksafe.com/files/Toastie/zx-spectrum-and-9750/ZX9750.m4v Best wishes, Thorsten

Maybe worth mentioning that the "program language" is encoded with TLG's very own visible light link (VLL) protocol. The same is true for the MicroScout; it talks VLL as well. The code set is a little different for the two PBricks (https://www.eurobricks.com/forum/index.php?/forums/topic/188584-mulpi-a-multiple-lego-remote-protocol-interface/). In addition, TLG's USB IR tower had a "visible" (white) LED in addition to the IR LED (on the serial tower); BricxCC as well as TLG's "Scout tool" know ho to operate that feature. TLG never made a USB driver for post WinXP operating systems, which is, well, the modern and typical TLG style behavior. In other words: Bastards; they just cut it short. VLL protocol, the plastic fiber optical cables, MicroScouts, CodePilot, wonderful, all TLG stuff ... and the best part is: The SCOUT PBrick natively talks the VLL protocol, and can operate both, CodePilot and MicroScout PBricks - just use the output "C" (which is the SCOUT's visible LED mounted on the front, not white, but bright red) ... All the best, Thorsten

Lil' teaser (I know, this audience is really small, but so is the world) Finally, I got my Speccy to talk and listen to 9750. I tried the 8255 PIO first - total and utter failure - and then the 9771 approach on the Z80 bus - bummer as well. Why? 1) Stupid me. 2) - 9) see 1). 10) I need to edit the first post 9771/9750 thread regarding the decoding of 74LS373's - it is even better than I thought. The ZX Spectrum is another computer (introduced 1982) now happily operating 9750. And yes, the magazine in the background is mine from 1984 and yes, this is a carved-out ZX printer case (with the 40 pin socket for the failed 8255 approach and a bread board in the back, along with 2 74LS373's and one 74LS02): The coolest thing though is: I still speak a little Z80 machine code - and as said before, used to crack the copy protection of Spectrum games back in the days - in return for TTL chippies, people "had" to buy me More to come. #8bitisbetter! All the best, Thorsten

This one? Best, Thorsten P.S.: If not, then google >eurobricks "Mill Village Raid"< with the quotation marks, there are a few more hits pointing to EB

Pure blue gold. Crazy. And incredibly, nicely done. For me: Un-be-lievable what you have created. Congratulations! Who? LEGO? Or TLG? No. They don't. They look at profit only. But there is nothing wrong to wish for that to happen. And: There is more than TLG on his planet. All the best, Thorsten

I do as well - and I wonder how I could live for so many decades without ... When it comes to desoldering 40-footers (or any chippy, particularly the 16 pin 4164 RAMs), Adrian's heat gun trick + the nifty curved toy (made one from 2mm dia garden wire) does it for me. Best, Thorsten

This is the first time you did something like this??? And you are not 100% happy with the result? OK, I can see that - because you are 150% happy, right? I am not into RR, but that shirt along with the print is >super cool<. I love it. 1999 ... time flies. All the best and thank you very much for sharing! Thorsten

As @JopieK said: Am besten testen ... Simple multimeter is fine. The lamps should read rather low resistance. The sensors maybe 500 Ohm or so, when pressed. If the resistance is much higher (or does not change at all when pressing the button) then you need to open it up. I'd try something similar to the lamp approach in the link as well. Lab power supply for the lamps (not for the sensors!) is fine but maybe not at hand (?) ... a 4.5V battery will do as well, the historical type 3LR12. Do you have the 4.5V wires as well? They will make things easier to check. Best, Thorsten

Well, that is not exactly true. The CyberMaster PBrick (CM) has a whopping 396 bytes of free RAM available for storing LEGO byte codes (as the SCOUT has as well). Sounds not that much, but you can do a lot with the CM specific commands and functions! The tacho motors alone are a blast. The easiest way to program the CM PBrick is BricxCC/NQC; TLGs own PBrick control programs can do that as well. The CM RF tower behaves exactly as the serial IR tower for the RCX, SCOUT, Spybotics. All the specifics of the CM PBrick are in the NQC Guide file: I just fired up my CyberMaster PBrick and took a screenshot - this is what I got upon a little analysis run. As you can see, the CM can run 4 tasks and 4 subroutines in parallel. It has 32 (global only) variables. BTW: When the CyberMaster PBrick noticed, you called it a "hub", it played "Hell's Bells" (yes, the built-in sound features are cool!) All the best, Thorsten P.S.: Here is a link to one of TLG's documents - there actually was a time, long ago, in a galaxy far away, when they accurately documented their hard/software stuff: http://www.activevb.de/rubriken/mindstorms/downloads/pbrick.pdf

You mean regarding the PBrick having two built-in motors, sensor inputs, wireless communication, right? The basic concept of programmable LEGO stuff - as with all other microcontroller based technologies way before - has been essentially the same since the 4.5V Technic Control era from 1986: Sensor reading -> input to controller -> processing of input within controller -> output of controller to actuator. And the latter may affect the reading of the sensor and that may be used for setting up feedback loops. Yeah, I know, everybody knows that. And since 3 and 1/2 decades, LEGO line followers are reinvented ... Of course, many things have changed over the past 3 and 1/2 decades [computing power in general; #inputs and #outputs (well, not that much in LEGO world); communication means (cable, IR, RF), protocols, and speed; sensor/ADC resolution, sensor types etc. pp.]. But the concept naturally remains the same. One of the nice things about CyberMaster is that once you learned to play with LEGO byte codes, you knew how to program RCX', Scouts and Spybotics as well. Even better, with NQC you even had a C'ish programming language, which simply translates your code to LEGO byte code. And with BricxCC and IDE, which allows you to monitor CyberMaster PBricks as well as the other PBrcks listed above, even CodePilot and MicroScouts using VLL when you had the LEGO USB tower. The 27 MHz band CyberMaster is using as RF carrier frequency ... was a bit congested back in the days, as no Wireless Communication Police would show up even after blocking the entire 27 MHz band with a 10kW RF generator . Today, that frequency band is mostly nice and clean again - as we even run microwave ovens in the 2.4GHz bands - where BLE is also sending its data packets through the ether. And we switch to 5GHz as it becomes as congested as 27MHz was a long time ago. Best regards, Thorsten

Mind control (https://hackaday.com/2021/05/24/self-driving-or-mind-control-which-do-you-prefer/)

Success! Desoldered the faulty 40 pin Yamaha chip, soldered in a 40 pin socket, popped on the working chip - and - works So on to the video ... I suck at taking videos, though. Best, Thorsten

Of course, you can! You know how many totally silly and totally irrelevant (to the Uninterested) "certified world records" there are recorded in the annual Guinness World Records book or on their website? OK this is not certified - but hey, this is fun! I enjoyed it! And they're saying "... so for now we're claiming the record." Yeah, why on Earth not? Take all your LEGO flower elements you have, put them on a trailer, and claim, for now, the record. What is wrong with that? Nothing! It's called having fun. I cite from one of my favorite movies: https://movie-sounds.org/war-movie-sound-clips/quotes-with-sound-clips-from-kelly-s-heroes/oh-man-don-t-hit-me-with-them-negative-waves-so-early-in-the-morning Congratulations guys, I did not find anything either - 72 meters - WOW! Best, Thorsten

Hmmm - all difficult: 1) Tough to fire a company, particularly one that ceased to exist in 1945. Or make it 1969 when they dissolved into MBB. 2) Rudolf Blohm - dead; Walter Blohm - dead; Ernst Voss - dead (well, they founded B&V in 1877 ...) 3) That plane did fly for the first time in 1938 ... What I like though that you made me find this thread from 2015 - otherwise I would have missed it. Love that build!

I boldly agree to your assessment, without >any< harsh feelings on this now "growing up generation" - they acquire other and more relevant skills in the world developing on their growing up. Every poll is - as you said - naturally "skewed". You can come up with as many rules as you want; it will remain skewed. More or less. Homo sapiens (sapiens) sounds good, but after all, the time to develop educated skills for an "unbiased poll", was - and will be for a long time - a little short. Best wishes, Thorsten

That'll take some more time than originally planned - yesterday I fried 2 of the 8 IO ports of the Ataris's Yamaha sound+I/O chip: "Thou shall not" ... connect a ribbon cable the other way around to the outputs of a parallel port driven by a 40 pin I/O chip". Particularly when there are additional shorts caused by sloppy soldering But: The financial department here (=my wife ) cleared the acquisition of a rather cheap desoldering station as well as the purchase of 2 used but functional Yamaha chips ... Will try (very hard) to get back to #8bitisbetter behavior, for example: "Thou shall not hot-plug on ancient computers" Best, Thorsten

Thank you very much! The 1x tiles have anti-studs with an indent slightly smaller than 1.5 mm. I use these as a guide for a 1.5 mm drill (on my drill press) to drill "pilot" holes. Turning the tile around, I try to scratch mark the position of the hole in between two pilot holes with a sharp wood piercer(?), once it looks OK, I pierce a little more, then take that mark as pilot for the 1.5 mm drill again. Last step is widening the 1.5 mm holes with a 3 mm drill (for the 3 mm LEDs). The drills (for metal) have never seen metal, only ABS and wood. [BTW: The drills in that box are really sharp; I thoroughly checked that by (OK, sort of accidentally, but still idiotically) drilling into my left index finger using the 8.5 mm drill. Yes, sharp the thing was. But: A small piece of wipe paper, some duct tape and a bottle of beer ensured that I could proceed with my project ] Best, Thorsten

Hi Evan, I studied the schematics of the Sinclair ZX Spectrum a bit and read some moldy magazines (the original paper versions, 1983-1985). It turns out that 9771 with the help of a custom cable (Spectrum female card edge connector to female ISA BUS card edge connector) with no further electronics needed, should work well. All you have to do is getting the two connectors, solder that cable and that's it. As I don't have another 9771 (and don't want to get that one card I have off from my XT), I can't try this almost pure LEGO approach. Would have been funny though when TLG had put 9771 into a slick (empty) black ABS box and then sold it off for crazy amounts of money to schools. The native Spectrum BASIC has the command "OUT address, byte" and the function "byte = IN address". So we're all set. Best, Thorsten

From breadboard to perfboard I just finished cleaning up the mess around 74LS273 on that breadboard - by putting it on a perfboard and do some soldering. The Atari 9750 parallel interface (left) has now a similar shape as my serial 9750 interface (right), I tried to (very, very) remotely give it an Atari-ish shape: As Atari (ST) cases appear to age nicely over the decades (the ST I am using was born in 1987, at least the PCB says so) - others call it yellow/ing, same thing that happens to mostly white LEGO pieces - I thus chose tan bricks and plates to sort of match that The top cover is pure 999 Gold - these are tiles from the MK Flying Dutchman stand I did not find any use for, as my FD is plowing through LEGO water up here in the attic . These are the parts used - and yes, I did some cutting, otherwise a snug fit of the board, so that the cables (to 9750's port and to the Atari's parallel port) can be securely attached/detached, is tough to achieve at this scale: Left: Interface partly assembled. Right: The light attachment is for trying things out, which don't need 9750. I did not include the two input/sensor LEDs, as it was already a pain in the butt to get the 6 output LEDs in there. Furthermore, the inputs of the interface require TTL voltage levels, so that e.g. the TC light sensor won't function at all. Left: Front view [power is 7-25V DC, 9V, 10V, and 12V LEGO DC power supplies work well; 11 ribbon flat cable (STR#, D0-D7, GND, BUSY) that goes to the 25 pin parallel port of the Atari]. Right: Back view (either the LED attachment is plugged in or the 20 ribbon cable that comes with 9750) The interface with LED attachment: Some very short video showing the interface in action to follow. Best regards, Thorsten

Heavens - this should not be anywhere near a dilemma ... you are selling Marvels of the Universe ... and $400 is a very low price! I believe a bit more of advertising may help? Pictures of the content (I guess the boxes are "unopened" - no need to do that, as we apparently have video?), some nice words about each item? And then: Maybe telling folks the prerequisites for running that incredible stuff? Yes, we are in a very well-educated LEGO forum, but when going that much back in time, the set numbers alone - I believe - may not make that much sense even here. I may be very wrong on this (sorry folks!!!) but this stuff was sold to schools and was hardly available to the average LEGO customer. When you google the numbers, not that much of "trusted content" shows up. I'd - as said - would advertise a bit more, and graphically. After all, 9771 is pure Unobtainium. 9750 is on BL for $50 (EU, only 2 items!!!). 9700 for $100 (US, only 1 item); all + S&H. Again, your offer is very reasonably priced! I asked around in my university today - not much of a response; the folks I work with are all weird chemists - they believe that ABS is a bit outdated. In my research group, they believe everything before 2000 is - Tomb Raider stuff. The physicists - well, are physicists. The don't even have a remote idea regarding element 42-4 in the Periodic Table.: Unobtainium. I will push on. Sorry that I failed so far. All the best, Thorsten

I absolutely don't think you have broken a taboo. For one, there is a more than 35 forum pages long CADA thread right here in this forum. Secondly, for heaven’s sake, all you have done is looking around for what competitors have to offer. In a capitalistic world!. People keep telling me that >competition< is the best driver in that world and makes everything better. So, when I want to buy a toaster, I don't buy the most expensive (but still relatively small) toaster on the planet - only if that one can do so much more or better than the competitors' toaster can. In the toaster industry, all critical roasting and toasting patents have since long expired - it is the same thing with the plastic pieces we are discussing here. So no, what you have done is the most natural thing in this world. Are you alone? Certainly not. If you want to speak openly, just go to the community forum and check for folks who did, do, and will continue to do so: See with open eyes what is out there. It is entirely up to you. And when asking for $650 you know what? I'd look around A LOT. If this cannot be discussed here, then I don't know ... Best, Thorsten

Yep. It appears to be an essential part of the GoG (game of grift ) Best, Thorsten

@evankChecked about prices - these 8 bit beauties sell for high prices, so I am out of the game (apart from the Speccy, of course). Also checked with the Atari Gurus on their forum - they said, nothing is wrong with the circuit I posted above. I'll make a little perfboard version of the Atari interface just to have the two (Arduino and 74LS273) ready to go. Need the breadboard for other stuff. Best, Thorsten

Uhmm - I never thought they were gifts but the usual "for free" thing, did I get that wrong? The "Get one - get one for free", "25% off if you purchase 2", or "the GWP will make you rich beyond your wildest dreams" (OK, heavily copied from GB, the original, of course). Thorsten