Back in 1979, I worked on an industrial controller that used the MC14500B. I was shocked that there were 1-bit controllers on the market. Carl Todd wrote the code and I wish I had kept a copy.
Yes, it was a nice way for hobbyists to entertain themselves with the original Altair on its own without the need for any terminal or printer or keyboard
Thanks! That's definitely the aesthetic I was going for! I think with some smaller traces, but a similar design style, I can really closely replicate early 70s PCB design and really get the PCBs looking great. I only wish I could figure out which side the KB marking would end up on, haha.
Thank you for also going over the mistakes you made. It makes your presentation feel honest and allows us viewers to share in the possibility of learning from those mistakes. Your bodge wires follow the same design esthetic and look really neat as a result :-). The traces resemble a Disco-style font.
I like your design style, whether for CNC or PCB. The CNC ones look absolutely beautiful and the PCB one without the solder mask and silkscreen is great too. More expensive = more beautiful. Great project.
Thank you so much! I haven't really come up with a great way to do double sided PCBs on the mill just yet, so I wanted to see how an etched double sided PCB designed in the same style would turn out, and I'm quite happy with the result!
@@UsagiElectric I would say Go For It, they will look beautiful from both sides! I have not seen such a consistent and artistically nice design for pcb’s before.
I really like how you've mounted the switches through the board. It brings stability to something that COULD be pretty fragile. And amazing work from Yaro... to make such a minimal system do ANYTHING is pretty fabulous. I remember seeing a story on TV about the great applause when somebody got an Altair-1 to "actually do something"... and an Altair-1 is GIGANTIC compared to your MC14500 system... :)
I always hate it when switches or push-buttons are rigidly mounted and strong enough to withstand the forces of an uncoordinated human like myself! And Yaros absolutely killed it! The MC14500 is really just a fancy ALU, so to be able to get just 14 ICs to do anything is impressive.
That coarse-pitch swoopy design and maskless HASL finish is great, looks very much like a brand new board that just came out of a time portal from 1975.
Pretty cool. Can't wait to see it run on the UE14500 vacuum tube computer. BTW, I think you can eliminate one NE555 in your clock circuit. To run in step mode, just switch the discharge path by connecting to a N.O. pushbutton to ground instead of pin 7 on the NE555.
I have no idea how this video fell out of a crack in spacetime exactly when I needed it. I have been itching to build a retro computer of some sort for a while, The MyNOR and Gigatron are high on my list (and might end up building both anyway), but I got sucked into reading a few Hackaday articles on WDR-1 replicas and other MC14500 machines. Well I hardly ever do this but I impulse bought a bunch of MC14500s on EBay and almost immediately had buyer's regret. Am I ever going to get around to building anything with these? Well... then I thought to search RU-vid and... what? within 24 hours of picking up these insanely esoteric old chippies, THIS pops up? Instantly erased the buyer's regret. This video is brilliant - great descriptions of what's going on, and that PCB design is amazing. Not sure whether I'll use the Gerbers or do my own board - but If I do I probably won't have the patience to get those curved traces just right!
so cool to see this! I did some prototyping with this guy...you just have think very *logically*, but surprising what can be done, and in a very robust system!
You may like to use a DS1813 (from Maxim) if you need to have everything stabilize before starting. It will hold a reset line low (negative logic) for 150ms upon powerup, and it's extremely easy to add a pushbutton to cause a reset. I use them on my SBC projects. It's in a TO-92 package. You could also use an NE556 to save a little space.
Interestingly, the stabilization idea wasn't for startup, just to let the ROM catch up before the CPU executed some instruction for every clock cycle. But, turns out the MC14500 doesn't particularly care, so it must be doing more on the falling edge than I was initially thinking. And, I totally would have a used a 556 if I had one, but I've got like 40x 555s, so I figured I should use some of them for something, haha.
Understanding the electronics your code runs on or at least the basics of them can really enhance your coding skills. No just know something works, but understanding why it is so, can be very helpfull. Everything boild down to those most basic bits. For app developers it matters little, but if you write high performance C or similar language its very usefull.
@@bzuidgeest Oh yeah, started out learning C when I was young. I think it setup a lot of the right mental structures to frame the rest of my learning later on. Makes picking many other languages really easy because I already have a frame of reference for what is going on behind the scenes. I have dabbled in assembly, wrote clone of robots on linux using syscalls, but never dug deeper. My experience is 'digging deeper' into how things works yields many rewards especially in a very highly interconnected knowledge space like computer science.
I thank the almighty algorithm for recommending this video to me. If only you knew how much I love this kind of PCB art. This is heaven 😍😍😍😍😍 New subscriber here. !! 👍👍
Thanks ofr picking this up again. I remember when the MC14500 hit the 'shelf' of the electronic engineer community. Studying the chip and how to setup the hardware around it to actually make it a computer was quite interesting. I really was a good teaching subject, for example what really has to happen on a (conditional) jump. --- When it came to my real first kit though, it was a 8085 on two small boards, one w/ CPU and memory - RAM and ROM w/ monitor, two 8 bit latches for input and output, and a 1k monitor. Because hardware was expensive, the 6 seven segment displays were software driven: so when the CPU was doing something it went dark... it cassette tape interface was available to store and loed programs... after all, it was all hex keyboard entered. Keep going, its fun to go back to the future.
How DOES it (conditionally) jump? Since the instructions just seem to flow from the ROM in numerical order, fed by the external, separate, address counter.
@@greenaum Use a loadable counter and a few other simple chips and wiring and use the nops' hardware flags to trigger loading the counter, inc and dec stack pointer, etc. My comments were not made in reference to the particular hw setup that usagi implemented in his schema / on his board or its capabilities and limitations. I'm sure there is literature still available illustrating setups with that and much more capabilities.
@@allobject Sure, not sure the setup our dude made allows that. But it does apparently contain jumps! It has to in order to react to the inputs, at least I think so. Seems like programming the 14500 is very different from normal programming just because it's less than half of a real CPU. Like it just streams through it's instructions and moves a couple of bits here and there and it's up to you to make a computer, or whatever control system you want. Incidentally I wonder if, in the early days of home computing, anyone ever used one of these in a real computer with a display and keyboard. Or at least, say, a serial port. Would be amazing to get BASIC on it, but I imagine you'd end up implementing a proper CPU in your own logic and having the 14500 "emulate" something better. 6502 doesn't have a lot of registers, you could maybe do that.
@@greenaum actually there are no conditional jumps. The whole program loops forever from address 0 to address 255. But MC14500 has a way to deal with it. The only conditional logic required is the setting of the initial value. And OEN is an instruction that allows to conditionally disable memory writes. It essentially makes the initialization code to have no side effects, and even though the CPU executes that code, no writes are happening.
@@greenaum indeed... it would need a lot of memory and cycles to getting something like a home computer even for those times going. On the other hand, I enjoyed writing an arithmetic library for the basic operations w/ integers as a thought exercise. I did not have the means at that time nor the support to get that going, even though the journal I read about it showed an usagi like experimental board. Similar fun I had for the COSMAC RCA CDP1802 - about the same time, also CMOS, but 8 bits - because of available in the field (and space) on battery power. The 6502 came to play to in my first ventures on Apple 2E(?) with virtual machine executing USCD Pascal... (there is really no new Java coffee under the SUN... haha... was all there long before... and was very disappointed about how weak Java started out... and goes only 'strong' because the IDEs do for it what other setups had built in from the get go). Some stuff is still tickling my mind for enjoyment...
No solder mask. Love it! I still have a blank first-off PCB if a 16-bit microprocessor system that I designed in 1983. It did have a basic silkscreen, but the mask was left off to aid visibility of the traces and to make any fixes easier during the initial debug.
Holy moly, this board looks nearly like hand-traced PCBs of the 70s and 80s. I guess with how good PCB design has got, it's not far-fetched for PCB fabs to make something that's old-fashioned, considering people can make traces in the shape of a picture now.
I've wondered about a computer based around that family of chips; thanks for building & sharing! I also have another idea: see if you can turn it into a basic 4-function calculator.
Thanks for checking the video out! And a four function calculator isn't impossible, but will require a lot more memory, both for the program and for RAM. But, once you have enough storage space, you can really get the MC14500 to do just about anything. Taking the concept in this video and expanding it to a full fledged homebrew with UART support and a proper amount of memory is something I'm slowly working on in the background, and will hopefully make it to a couple videos someday!
@@UsagiElectric Thanks for responding, and I'm really happy to hear you have a long-term plan for a proper micro-computer around this chip set! Even though it's externals are 1-bit, the heart is still 4-bit, so I'm super excited to see what you can do with them! Also, you mentioned a UART for communication; do you think the classic Hitachi 2x16 LCD display could fit right-in on this type of machine, since it can be set to use a 4-bit data input, with only a few other lines for control?
Well, this was a fun little diversion. That board looks fantastic, but I most appreciate the fact that you're willing to point out the mistakes and bodges...makes me feel a lot better about every board I try to make.
Beautiful board. I love PCBWay, they do such a fantastic job on all my projects. However they do not yet have the technology to overcome my mistakes and it usually takes at least a couple tries to get things working.
I do enjoy PCBway as a sponsor for youtubers. Haven't heard anything bad about them, they don't demand long ass ads like some -cough raid- and the product is relevant to the videos they sponsor. Haven't had the need to order anything from them yet, but when i will i know which company i order from. Unless the prices are dumb high, but it really doesn't seem so.
I've been entertaining the idea of wiring a MC14500B to a STM32 series processor, implementing the memory and control logic in the STM32, and also building in an editor and compiler. It'd even be easy enough to add an SD card so you can transfer files to a PC to store in Github or whatever. I have a largish collection of TIL311 hex displays, so I'm considering using those to display the address and data bus, plus a few LEDs for the status bits, result register, etc. BTW, what PCB design system are you using that doesn't generate warnings for unconnected nets, etc?
Very interesting. Once again, bringing to light another obscure topic (and chip) that we might not be aware of. Was wanting to dive deeper, but your Github link for schematics/gerber yields a 404. Super interesting. Great work !!
Thank you! As for the link, that was Github and RU-vid not playing nicely with each other because there was a space in the folder name. Should be working now!
@@UsagiElectric There doesn't seem to be a UETTL repository in the Nakazoto Github page. And except for the Centurion repo, none of the other 6 have been updated since December 16th, 2022.
@@JCWren I accidentally had it set to Private instead of Public, so I was super confused why it would open for me and no one else. It should be Public and accessible now!
Loving the retro look. The curved traces look amazing. If it were possible, I would plate the traces with something like nickle to prevent rusting. As a design alteration suggestion, I'd be inclined to use a single 556 timer chip instead of two 555 chips, but that's just my opinion.
Thanks! The traces are actually covered with HASL, or Hot Air Solder Leveling, by PCBWay. Meaning that there isn't actually any exposed copper, it's all essentially covered in solder. While not as resistant to corrosion as a proper soldermask, the traces shouldn't corrode for many years to come (just like regular solder on through-hole components). The 556 would have made more sense, but I didn't have any and I had like 40x 555s, so I wanted to use some of them up, haha.
Your PCB reminds me of the Cambridge Mk14 computer board and of my first real computer the Ohio Scientific Superboard II. The Superboard II got me into the world of computers for the last 40 years.
Great job, I really like the things you do. I built a 4-bit processor running at 27.125 MHz 40 years ago. I also made some games back then, I even sold some, but today there is none left to prove what I did. I used the famous 74181 at the time. Again, congratulations on your work. Your PCBs are well made, are you using a CNC? I use vinyl sheets and a laser to make PCBs. Using this process, I can pass 2 tracks of 8 mils between 100 mil pins!
A little tip so that you dont miss unrouted air wires, zoom all the way out so the board is as small as possible, and click on it with the route tool, and that will make painfully obvious the air wires you have missed, that has saved my ass a bunch of times.
I love the Art Deco look of your boards. (I just cannot imagine a sensible Art Nouveau PCB.) By the way, do any of the pushbuttons need debouncing? If so, how do you handle that?
To lift a trace, try soldering a piece of wire at the end of the trace. Then pull up with the wire. Also recommend scoring the trace, where you want the break.
Looks like a Teac 4010 sitting on the shelf, I have one too!(and a 6010, and a 2300). Nice job on the one bit computer! I want to build a 4-bit alu with discreet transistors...... time....
To remove the errant trace, cut where you want to where you want to disconnect from the other track and then set your iron to 350C and solder and flux sliding the iron tip back and forth along the track to be removed. It will just come off. BTW, a decent PCB layout package will have on-line DRC flagging that sort of omission.
I wouldn't be too worried about the mistakes. I've been doing hobby electronics for over 20 years, and I still make mistakes. It took me 3 PCB boards and two rounds of troubleshooting to find the mistake in my last design. They were all home made, otherwise I probably would've given up after the first fail, which ironically wouldn't have happened if I got the board professionally made. And by "given up" I mean bodged in hacks to make the board work after I found my mistake, exactly as you did.
I'm new to all the engineering involved in such. I speak "component" and "code" to a large extent, though. Ordered and got my first empty prototype boards (A1, A2.... holes) where I can just draw the circuit on it and follow my ideas. My solder skills went to the top just recently. Your board is beautiful and I have no idea what you want with it without a display (x.y dots and letters) and no keyboard.
Very nice, looks awesome and making mistakes is how we learn. I would suggest a through hole PCB 9v battery holder on rev 2 , to get rid of those flying wires.
This is just brilliant. Thanks for sharing and making it an open project. I think I will order the PCB and use it to teach my kids about low level computer design. Is it difficult to get an MC14500 in hands?
Better yet, put a single cut through the trace each side of the section to be removed. Then apply heat from the iron. If you go straight to about 450 degrees Celsius, that will often soften the adhesive enough that the piece of track will then lift pretty easily with very little persuasion. If it's only short, it may even come away on the bit of the soldering iron.
seeing those bits spin around the register reminds me of my attempt at a minecraft turing machine. exept instead of the logic being built of redstone, its built of code logic. i never played kill the bit, i mostly just used it to make streams of 1's and 0's. but I did get it so that for instance, it could spin the register and copy one end to another to move data. with minimal work, i could have been playing kill the bit
I still have my MC14500 based SBC on breadboard, trying to migrate to a slightly more permanent solution on veroboard. Currently modifying my design for providing the input register with press button set / reset selectors using 74LS74 flip-flops. Thanks for the latest video, helps to keep my interest going and providing me with the impetuous to continue! I hope this isn't an imposition on your generous nature - is there any chance you could make the 14500 (byte) code available as compiled (I'm unlikely to be able to do a compile on veremenko-y's listings). Thank you.
@Usagi Electric, to make alligator clips easy to attach, drill a whole (at the board edge or two close to each other) slightly larger than the chaw of the clip and put a hallow rived into it. If the board - your legs from the 741 or 555 - i done bay a board manufacturer, instead of rivet a thru contacting works.micro:bit uses that technique. My approach was to solder in a 'ladder bar' from a wire in the shape of an unused paper staple. It is easy to all kinds of clips and (instrument probe) hocks, and can accommodate even ore than one...
I have one of the original 1970's data books, I did a big clean up of what's useful and decided that the MC14500 was just too unique to discard. Question, where do you get MC14500s ??
The hardware is amazing. I wouldn't have thought a 1-bit CPU to be practical. However, if you chose your instructions carefully, I think you can get by on 16 instructions. The game is neat, but I am not good with reflex stuff. I wonder if you could program it with a NIM-style game whereby you take turns removing a "match" from a pile or row with the object of you forcing your opponent to remove the last "match". You'll need an AI opponent and to control some decent number of LED's (traditional NIM uses 16).
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Nice video! Be careful, as you used cheap "disposable" IC sockets. You are going to get bit one day!
There was a computer using this build by a show running on the German TV channel WDR, that one even faked jump instructions by sacrificing the second half of the ROM. One byte for the CPU and the next one for some TTL shenanigans that either go to the PC counter or not.
I've been entertaining the idea of implementing a variation of the Simon(R) brand electronic game using a 64x2 shift register, an 8-bit input shift register and 8-bit output shift register, some 8-bit registers, and an EPROM. The shift register wouldn't be large enough to hold a pattern for people to guess, but would be large enough to hold a pseudo-random number generator and seed, along with a count of how many sequences had been correctly replayed. I think the EPROM would probably have to be bigger than the ROM in the actual game, but not absurdly so, given that everything outside the ROM would be simpler than in the actual game.
Check out the Nebula, A serial delay line discrete transistor machine built at Oregon state in the 60's. Gary Oliver was the curator at OSU comp center in the mid 70's. I saw it run. Not as popular as the campus CDC 3300. Fast enough to drive a line printer. Since the early 80's I've wanted to build a single chip implementation to hook to a single DRAM as a 2 chip solution.
Really cool Project. If using SMD-derivates and Multilayer-PCB's you could make it even smaller. Sadly we don't own a multilayer-press at work yet, cause it's pretty expensive. But we're still etching the pcb's ourself.
This is really cool and especially the ability to play a game on it. On the side though, I feel if your voice recording was converted to mono it would be easier to hear you without your voice phasinng around my head.
I never do PCBs without solder mask because it's just too easy to get bridging that is both harder to see and harder to remove. I also always tent my vias on a through hole PCB.
is there a link where we could buy all the ICs used here? I'm newer to learning electronics like this and it makes it hard to know exactly which ICs I'm looking at & their functions
I was just thinking that you could use one of those rotary bit selector DIP switches for the ROM addressing so you could get maybe 8 different programs to choose from out of the ROM. Thanks for another great video. I always enjoy seeing your projects come to life. It is amazing the tenacity and enthusiasm you have to solve problems. Keep up the great work! Cheers.
Would say a BCD thumbwheel switch would suit this better, with then 10 programs being available, and with the option for a second one to add in 100, as after all the memory needed for all 100 is still well within the capability of a 2764 Eprom, which still will more or less fit in with the time period, and match well. Just need to add in the 9 pin SIL sockets for the pull up resistors, and a 100n decoupling ceramic capacitor across the EPROM, which will be about the only thing there that is power sensitive.
@greenaum ...MC14500 (conditional) jump and subroutines: JUMP, (Mnemonic: IMP). The JMP instruction generates a one clock period pulse on the JMP pin of the ICU, beginning on the falling edge of the CLK signal. This pnlse can be used to gate the jump address into the program counter. SKIP IF RR = 0, (Mnemonic: SKZ). U the Result Register contains a logic 0 at the time the SKZ instruction is executed, the next instruction is ignored by the lCU. (i.e. no action is taken.) Together the JMP and SKZ instructions give the lCU a conditional branch capability. To add subroutines to the ICU, a Last In, First Out Memory (LIFO "stack") is required. If the subroutine feature is required, the most economical method of implementing this feature is to have a LIFO stack in which the top location of the stack is a parallel-loadable counter, where the outputs of the top location (counter) are available as address lines. The ICU does not have a JSR (jump to subroutine) instruction; however, both of the NOP instructions create control signal pulses and either could be used as a JSR instruction. This pulse can be used to signal the program stack to perform the "push" (store binary states) operation while the address of the subroutine is parallel-loaded into the top location of the stack. The ICU does provide a return (RTN) instruction. The RTN instruction creates a one clock period pulse on the RTN pin of the ICU. This pulse can be used to signal the program stack to perform the "pop" (return binary states) operation. After executing an RTN, the next instruction is ignored by the ICU. This is done because popping the stack returns the address of the JSR instruction to the top location in the stack. If this instruction was not skipped, the machine would be trapped in an infinite loop. ...as taken from Motorola doc - MC14500B_Industrial_Control_Unit_Handbook_1977 - Theory of operations of ...
3:32 There is no glue that holds the copper trace to the PCB. it's created from a negative and the remaining copper is removed away chemically leaving your traces. the traces you have a literally the copper plate that they started with, there is no glue holding it down
I literally have no idea 4-bit and 1-bit processors existed until this video. I feel dumb for that lol. I thought the moment we went to integrated circuits, we already had 8-bit processors as the norm. I guess having 1 and 4-bit processors doesn't sound too far-off now that I think about it.
Hey, sorry to be that guy, but isnt that a 1 BYTE rather than one BIT computer? Like I'm probaly wrong but i was just wondering. Either way, great work my friend, keep it coming!
5:19 you may try heating the trace with a soldering iron first, and then peel it up - may be a good test of how likely it is to peel up when you don't want it to, in the soldering process. Indeed a thing of beauty. I love the round traces. Horribly inefficient or not, very '70s style and actually possible to service and reverse-engineer without a microscope :) Might be an option to include an input from an external generator, in case the 100k pot on the multivibrator is not enough to slow it down to see every step you take, every move you make. Nice blinkenlights for sure. Nicht für gefingerpoken und mittengraben! A game of kill the bit, or whack a mole and smash a bug :). Sanity check... FAILED! Makes me wonder what if you plug the Kevin in instead of the MC14500 :) 22:26 is it a Tek scope I'm seeing in the bottom left corner? Intriguing... Oh, and a nice catfight.
