Starting a new project with a class 486DX processor, just to see what I can do with it.
Пікірлер
Awesome, it is nice seeing someone who mutters to themselves like I do. People often remind me of that. I am building a computer processor entirely out of transistors made from 2N2222 transistors. It is fun for me. Keep being you no matter what, you are a gift to the maker community. Many makers end up with so many projects they never fully complete one.
@michaelanderson654 Жыл бұрын
Custom CPUs are always amazing to see, and doing it with transistors seems that much more challenging, which is awesome. And thank you for your kind words!
@Fox-Tech Жыл бұрын
I am right now Developing a full 1970s era Supercomputer from only NAND gates (mostly because cheap) and its a really challenging task. i also have a upcomming project to make a Computer/CPU from transistors only. i am really facinated by everything logic, and its so cool to have your own computing things...
@curiouscomputer Жыл бұрын
Pretty cool! I'd like to know how it goes. My only question is how many kilowatts is that CPU going to consume?
@MK-ge2mh Жыл бұрын
@@MK-ge2mh I will post Videos about it on my KZhead channel... but also, it wont consume much power because Cmos logic is quite efficient...
@curiouscomputer Жыл бұрын
@@curiouscomputer I'll be sure to watch your videos. I thought I was replying to the original commenter saying he was building a CPU out of discrete bipolar transistors. Now THAT'S going to use a LOT of power!
@MK-ge2mh Жыл бұрын
Compared to the clean-cut high production value I'm used to on KZhead, the raw footage here shocked me with how much it felt like I was watching myself Quickest 20 minutes on KZhead!
@scrambledmandible Жыл бұрын
This is to my knowledge the first series about making a "breadboard" 486 computer. I've searched before but i never found any. Somehow i got recomended this and im very happy. I also have a 486 that i want to make a computer out of but I plan buffering the address and data bus with octal bus transceivers(I dont want to damage the cpu).I also plan to use an arduino or something else for clock,reset and other misc stuff its more easy and convenient(like have the arduino be controlled by serial)
@pesho9971 Жыл бұрын
Fascinating project! I've seen my fair share of vintage motherboard repair videos, but it's not often I see someone experimenting with a 486 like this, let alone designing a breakout board to do so! Wishing you the best on this project, can't wait to follow along.
@foxyloon Жыл бұрын
Ikr
@SonicBoone56 Жыл бұрын
I’m not sure they exist for 486, but for the older 386 and 286, there were several CMOS "static core" variants produced for embedded purposes, allowing you to run the clock at whatever rate you wanted, even stopping the clock completely without losing state. Some examples are Intel’s 386EX and the Harris CS80C286. Many CPUs of the era used dynamic memory for internal registers to save die space, and slowing the clock too far results in them not being refreshed frequently enough. It may be able to run very slow for now, but if you start trying to use the internal caches, the MMU, etc., fun errors might start happening :). Assuming you weren’t already alluding to it with your mention of the debounced switches, you can always go for the "button that asserts ready for a single bus cycle" trick. Edit: supposedly the Cyrix Cx486DX was a static core design.
@teknoman117 Жыл бұрын
Also the TI and CX SLCs DLCs apparently are static.
@njspencer79 Жыл бұрын
Keep doing what you're doing. The world needs minds like yours. Cheers.
@Eremon1 Жыл бұрын
Awesome! An idea came to my mind: adding status LEDs to the buses directly on the board would look great, but also could could double as a test bench for the CPU, for diagnosing ones taken from retrocomputers.
@LeoGitarzysta Жыл бұрын
I've played around with that, and now that I'm more comfortable with SMDs it would be easier. There is a limited amount of space as the board is 100x100mm and 4 layers, anything bigger then that has a huge jump in price.
@Fox-Tech Жыл бұрын
Wow! I did not know the 486 could be run at such low clock speeds. I'm studying to start working on something like this myself. Every 486 datasheet I've ever seen specifies the minimum clock speed as 8MHz. Being able to run it as this speed would make things a lot easier in the early debugging stages.
@scotts-tech Жыл бұрын
I wasn't sure it would work myself, but being that it's a CMOS chip it seemed like it should work that slow. It's still possible there might be other issues in the future, but it's been fairly stable in my testing so far.
@Fox-Tech Жыл бұрын
@Lurch Manually running the clock only sort of works, at least for a dozen cycles or so. After that it seems like if the duty cycles are far enough out of sync it goes into shutdown mode until it gets a stable clock again.
@Fox-Tech Жыл бұрын
The 486 does have an internal 8 KiB 1st level cache. I don't know if it needs to be refreshed all the time but if that is a requirement, than it would definitely limit the minimum clock speed.
@OpenGL4ever Жыл бұрын
@@OpenGL4ever I believe the cache is sram, though as I've yet to enable it yet, I can't say for sure.
@Fox-Tech Жыл бұрын
Dude this is amazing! Somewhere I've got the 486 processor from my family's first computer in the early 90s. I was allowed to take the computer apart once we upgraded, and I knew that the processor was where the magic happened, although I had no idea how. But I kept the processor, even though I was like 7 years old, and I'm pretty sure it's still in my collection. As I got into robotics with the Basic Stamp 2 and started to look for more powerful controllers, I always wanted to put the 486 into a project, but it was entirely inaccessible to my 12 year old self, both intellectually and on a hardware level. It's super cool to see a breakout for this old processor! You broke one of the main barriers to accessibility. Can't wait to see what you make out of this! Instant sub.
@evanbarnes9984 Жыл бұрын
My first CPU is AMD 486 DX2... I used it for maybe 5 years before broken. I salvaged the keyboard, Hard Drive and the CD-ROM but I didn't bother with everything else... I kinda regret it...
@da_pawz Жыл бұрын
Basic Stamp 2 and LEGO Mindstorms is also what got me into computing. My Boe-Bot was one of my most treasured Christmas gifts as a kid.
@teknoman117 Жыл бұрын
Wow! I am absolutely living for this! I’ve long wondered what kind of homebrew type stuff could be done with the venerable i486. Can’t wait to see more! Gonna be absolutely glued to this channel!!
@miketech1024 Жыл бұрын
This reminds me of an idea I had for repurposing older but functional CPUs: turning them effectively into some sort of microcontroller board, like an Arduino. Obviously they would be a bit bigger BUT they could be standardized.
@Voidsworn Жыл бұрын
Very cool project! I love it! Keep up the good work. I'm really excited to see more!
@nicomputerservices2669 Жыл бұрын
I cant wait to see your next video. I really like the design of your 486 breakout board.
@joshuamacdonald4913 Жыл бұрын
This is ridiculous and beautiful and interesting. I love the concept, the content, and the style. Subscribed.
@Nexxxeh Жыл бұрын
I really Love having found you, you are extremely smart, and even though the video is kinda slow pace for todays youtube standarts it was extremely satisfying to watch and i really enjoyed it a lot. id love to see more of your content
@curiouscomputer Жыл бұрын
Really nice to see people push the limits of breadboard computers beyond typical 8-bit DIP CPUs. This project looks amazing and made me an instant subscriber. Hopefully, in the not-too-distant future, this will inspire someone to go even further and make a breadboard computer using a contemporary CPU. Even a brand new Celeron would be incredible to see. Still, your work with the 486 is amazing and deserves far more attention.
@shalinpather4198 Жыл бұрын
Thanks for making this video. I'm glad it's not just me who mutters along to myself while working. You can always cut/ speed up sections of putting wires in if it's more comfortable. Great level of detail as well. It's easy to go too simple or too complex
@colonelbarker Жыл бұрын
Amazing project! I'd love to see where this goes in the future
@dylangreen6027 Жыл бұрын
that's very clever indeed! Thank you for your demo!
@tekvax01 Жыл бұрын
This is unspeakably neat; thank you for doing this and sharing it with us.
@shinypb Жыл бұрын
I remember back like 2004/5 in high school some friends and I were all in agreement that like, 386s and 486s are far too complicated for a homebuilder to ever build their own computer around. Granted that was in the days before easily designable and quickly available custom multilayer boards. But it's an assumption I'd been second guessing lately, so seeing this is extremely cool. Very nice work.
@starlightnixie Жыл бұрын
At this point I believe the Pentium / Socket 7 systems are the "very difficult" point. The bus protocol was never officially public, although the AMD K6-2 manuals have a very good description of the bus timing. It’s a synchronous bus so timing becomes a difficult problem. Totally solvable using FPGAs, but the signal count is high (like 250), so you’ll have to use a BGA variant.
@teknoman117 Жыл бұрын
Excellent project and rundown.
@MichaelDoornbos Жыл бұрын
Really nice Project, looking forward to the next episodes :) First time I got the idea of a the 486 as a managable processor and how it operates, havent looked into it very much before, but inspires to learn more about it. Keep it up, especially with the awesome one take :D
@LG-eq4pb Жыл бұрын
This is awesome. the 486dx was the processor I first came in contact with.
@ernie3444 Жыл бұрын
"A full breadboard computer with a 486." Ambitious! Nice. :) It's really interesting to see how the 486 connects up to everything. Nice to know it can run at much lower clock speeds than advertised.
@eekee6034 Жыл бұрын
This is so amazing. Keep up the good work!
@haskellelephant Жыл бұрын
This should be a fun project! Good luck with it!
@rehsd Жыл бұрын
Nice video i enjoyed it alot. Super impressive 🎉
@frankgrudge88236 ай бұрын
we NEED Ben Eater here, right now.
@rawexploiterp6951 Жыл бұрын
Didn’t realize I had a DREAM KZhead collaboration - but there it is!
@miketech1024 Жыл бұрын
Soon: The most over-engineered calculator, ever!
@veneroso3337 Жыл бұрын
You sell the boards and I'll be your first customer!
@skyking6989 Жыл бұрын
"The standard NOP... So yeah we're just going to start telling it do do nothing and if everything works it should do nothing. but it's the nothing that we are telling it to do. which is better than the nothing we're not telling it to do. That made more sense in my head." - Dude, that is hilarious. I want it on a T-Shirt just to make the 99.9999 % of the world say , "WTF does that mean?" It only makes in the heads of those who are fascinated by this kind of stuff. A very small club indead (I am a member of said club ) Carry on !! Cheers
@jlawrence71 Жыл бұрын
Even though it's doing nothing, it's doing something.
@SpeccyMan Жыл бұрын
So awesome… well done!
@BramStolk Жыл бұрын
My first PC ever had a 486DX in it.. apart from this video being purely awesome, it also made me feel really nostalgic
@zhsloe Жыл бұрын
Love it! What a great project!
@philb1466 Жыл бұрын
Awesome project!
@r_firefly4292 Жыл бұрын
I can't wait to se this evolve. I'm currently playing with a Z80 just to get me started. Uncut and honest video, i like that format :)
@frankjansson7563 Жыл бұрын
Thank you, I'm glad you enjoyed it! The format is inspired by a few other creators I follow, especially @weirdboyjim . I will probably be having some edits for timelapse in the future, or to cover problems with my current setup, but not to remove any content. Seeing the mistakes are half the fun for this sort of project.
@Fox-Tech Жыл бұрын
@@Fox-Tech Time lapse for certain parts is not a bad idea :) I was curius about doing something with an x86 but when I read that the minimum frequency was in the MHz range i hesitated. Seeing that you can i fact run them in the KHz range inspire me to build something. Can't wait for you next episode in the 486DX series :D
@frankjansson7563 Жыл бұрын
I would love to see the next video on this is awesome. I miss my 486. Also new Subscriber.
@DiyintheGhetto Жыл бұрын
Fantastic project and a great learing tool, well done - package it and sell it!
@WilliamLee_Exalted Жыл бұрын
Thank you!
@Fox-Tech Жыл бұрын
Damn. 486DX was my first PC at home. Didn’t expect to see it on a breakout board…
@AB-pb8oo Жыл бұрын
Love the concept of this. Watching to see how far you can go with off the shelf modern parts. Could be a way to have a nice PCI setup as the 486 PCI boards are either really bad or extremely rare and expensive.
@waytostoned Жыл бұрын
PCI is way more involved than what's needed for a bit of RAM and ROM. My EE course where we did microprocessor interfacing we just did PC bus (as in original 8086->style) which is simple enough to do with simple gates and latches. For PCI you need a fairly complicated state machine, especially for the discovery and initializing.
@thewheelieguy Жыл бұрын
It's pretty cool. Hope down the road you can add a simple video card and sound card. Wish I knew how to build stuff like this.
@gregbender7370 Жыл бұрын
This is really cool! As someone with a passing interest in this type of old computer some of this flies over my head but it looks like a fun concept. One thing I would suggest is maybe adding a socket to the breakout board so you could use other 486 chips from like AMD or CyrIx
@rof2877 Жыл бұрын
There is a socket under the chip, but it's a standard pin socket and not a ZIF socket (which are much harder to find, might see if I can scavenge them from old motherboards in the future) so it's not really visible.
@Fox-Tech Жыл бұрын
I hove we see new series soon, its so interesting. Subscribing now
@DIMONSE123 Жыл бұрын
This is a very cool project. However, I strongly recommend that you seriously consider increasing the number of ground connections. You don't appear to have any on to the board apart from the power connection. With wide busses, it will become very important that the ground for the signals doesn't bounce around when the signals switch. Even if you are only clocking at (say) 100kHz, the signals still transition between high and low logic states at the same speed as if you are running at full speed. The rapid simultaneous charge or discharge of multiple signal lines causes noise spikes in the local signal ground, which affects how other devices see the signals. (Research ground bounce for more info.) I'd recommend one or two grounds for every eight data or address lines, and more grounds where you are grouping control signals. While things may work OK reading static instructions from switches, it will very quickly get hard to debug unless you can keep the signals free of too much noise. This will only get harder with a breadboard compared to a good PCB design.
@GodmanchesterGoblin Жыл бұрын
Thank you. That's very good to know, I will research that and try to improve things. Right now the board does have a layer that's just ground plane, I don't know if that will help any in this case. Still, I will be looking into that and trying to apply it on future PCBs.
@Fox-Tech Жыл бұрын
@@Fox-Tech Certainly a ground plane is a good idea, but you also need to minimise the ground impedances between CPU and each area of the design that it's connected to such as the data buffers that you added, clock sources, decoders, anything driven by the address lines, and so on. Ideally, as well as the ground from the power supply, you will have direct ground paths from CPU to each other section, and they will also have their own ground connections back to the power supply as well. One of the difficulties is that the ground voltage spikes caused by fast ground current transients can be extremely short and very localised making them hard to measure. (Q... when is zero ohms not zero? A... When it's a 50 nano-Henries of inductance and the current spikes from 2mA to 100mA and back in less than 10 nano-seconds.) This all leads to the issue that each chip will see the same signal differently, based on it's local ground (at the chip inside the package) and that will be somewhere that you cannot measure even with a decent oscilloscope. This is why it's better to design high speed digital circuits with an over abundance of caution regarding signal grounds, rather than trying to fix the problem afterwards. But don't be discouraged. With the right research (which you've already demonstrated in terms of how the 80486 talks to the data-bus, for example, this could become a very interesting and rewarding project. I am watching with interest and admiration. (I have designed plenty of fast complex logic, PCBs, etc, but never around a 486 - and I have a DX33 in my junk box somewhere...)
@GodmanchesterGoblin Жыл бұрын
Good lord, what a project for a KZhead debut 😂🎉
@hgbugalou Жыл бұрын
ok, I'm already excited for the next part
@pentekimi Жыл бұрын
Subscribed for this, just wow!
@simondann7371 Жыл бұрын
It's funny that although tech has evolved (boomed) so much in the last 100 years or so, and there are things that are way faster and more efficient than this aging 486, yet I'm still finding it insanely cool to look at old tech, especially when a "modern twist" is added to them. Very very cool board, now please add a screen and run Doom on it.
@SaarN1337 Жыл бұрын
This is truly FUN 😀 My bet you have started a whole new trend. Now to integrate it into the Arduino world - then you will suddenly get support as you never dreamed of ... I just sub'ed as I find this project very interesting indeed !
@CXensation Жыл бұрын
Very interested to see how this will turn out.
@SonicBoone56 Жыл бұрын
Shut up and take my money.... seriously love the project
@greypatch8855 Жыл бұрын
i'd been curious to try something like this myself if i had some old processors to mess with. Would be fun to turn one of those old cpus into an impractical microcontroller or something.
@HobkinBoi Жыл бұрын
omg you totally rock for this pal!!! :-D
@ucmRich8 ай бұрын
The split into separate code address space and data address space was also available on the Motorola 68000 series as well, I think starting with the 68020. I hadn't heard of any 68K systems that actually used that feature either. In theory it could allow for better code security by locking out modifications to running code. It might also make it easier to map in ROMs without having to carve out a block of the address space.
@jbucata Жыл бұрын
Cool project :)
@ThomasPerl4 Жыл бұрын
This video is triggering my interests so dang much!!! I’m loving every bit of it! (Pun intended) I’ll be watching the next 2 parts now. :)
@Inject0r Жыл бұрын
This es REALLY INTERESTING 😮😮😊😊 !!
@francoisdastardly4405 Жыл бұрын
I used to design Intel based systems i386DX ,i486,i960 ,i860 .All had similar buses and needed epld 10 ns ( very fast back then ) to latch some of the bus control signal .The code was given by Intel in the hardware manual .
@ladronsiman1471 Жыл бұрын
Oh, that's cool. Feel free to tell me when I'm doing something completely wrong then! Actually, I think I ran into some of that code in question today, while looking for something else.
@Fox-Tech Жыл бұрын
Hey this is cool! Back in 05 I designed and build a computer using an 8085. I always thought it would be cool to make one based off the 68020, but that's a lot of wire wrapping! I'm subscribing to follow along!
@takingbytes1265 Жыл бұрын
Honestly, ordering custom PCBs is so cheap these days that I have become lazy and go for a PCB first … problem is what to do with the other PCBs I didn’t use because most of my projects are one-offs and you get a minimum of 5…
@teknoman117 Жыл бұрын
@@teknoman117 I would do the same. It's just that every time I sit down with the software It feels like there is a large learning curve. I got enough going on without having to take the time to learn it.
@takingbytes1265 Жыл бұрын
next video - Cray YMP on a breadboard :D impressive, seems like a fun project you have gotten yourself into!. I like it.
@AndrewTSq Жыл бұрын
I like it! Just today i ordered a PCB what extract the pinout of a 186 to a ISA Bus (for sure with custom pinout, but useable on a standard backplane). I want to do the same "Selfmade Computer" with it. The 186 uses A0 and BHE to seperate the lower and higher Byte of the 16bit Data. And yes, you can mirror/overlap a single memory Chip/adress space to two different locations 😅 Its nice to know that the 486 can work with 8bit components. And one of my first tests will be the lowest working frequency because i want to see blinking LEDs too
@K10driver Жыл бұрын
That sounds like fun. I don't think the 186 gets used enough, so glad to see someone doing something with it! In 16-bit bus mode, the 486 has the same A0/BLE BHE signals. That's one of thing that seems consistent throughout all revs of the CPU.
@Fox-Tech Жыл бұрын
@@Fox-Tech There are some DIY with the 80186/88 in the WW - but just a very few. Most of them are SBCs copied from very old schematics or pc-magazines. I want to start from scratch with something like a computer and not PC/Amiga or somthing compatible.
@K10driver Жыл бұрын
nice video thanks
@tonguescum5137 Жыл бұрын
Oh that's really cool.
@50shadesofbeige88 Жыл бұрын
I'm looking forward to the next episodes of this :) Also: I'm wrecking my brain on how to connect a single 8bit RAM to all four parts of the data bus. I guess I'd aim at 4 switchable bus tranceivers (74xx245?) connected to the byte enable lines and a 4xOR from all byte enables to the /CS of the RAM...
@superilu Жыл бұрын
That's pretty close to what I'll be doing, though using a 74139 to select enable the chip.
@Fox-Tech Жыл бұрын
You'd be far better off racking your brain since that is the correct English idiom!
@SpeccyMan Жыл бұрын
I am interested to see where this goes (and yea its similar to most processors, but its still interesting as most people wont go past dip packaged chips)
@osgeld Жыл бұрын
I could be mistaken, but as I gather, the 486 was pretty much the last of the "similar to other processors" before things like low voltage levels and specialized busses became a thing. The beginning of that trend is touched-on, here, in that even though you can tell the 486 to access individual bytes, it expects them on different data-bits depending on their alignment. Not difficult to do with TTL, but not "easy", either. (imagine its being connected to an 8bit ISA card!). So, at some point it became almost essential to have bridge chips to interface with the outside world, even if that's nothing more than a boot ROM. So, in a lot of ways the 486 is maybe amongst the last of the "similar" CPUs (Z80, 6800, even 8088) (and comparatively *really powerful*) that folk like us *can* "breadboard". That was a very exciting finding...
@ericwazhung Жыл бұрын
Oh wow, this is neat! I had no idea you could interact with an intel CPU like this without having a full PCI bus, north/south bridge, memory channels etc. It will be super interesting to see how far you’re able to get, eg if you write your own simple BIOS etc. Nice work man 👏
@foxiewhisper Жыл бұрын
Actually, a simple BIOS is in the cards, might be FORTH based just because I happen to like that language. :)
@Fox-Tech Жыл бұрын
I really like the idea and your presentation! A friend gifted me a beautiful 33MHz 486 a while ago, but I haven't had a way to use it yet. I wanted to make a board like this, but the datasheet seemed a bit too complex for a weekend project. Are you planning to share the board design? I'd even like to use this in my own YM2612 retro synthesizer design.
@ackfee6086 Жыл бұрын
I'm glad you like it. I wasn't sure of exactly how to handle this, and tried a few different things before settling on this one. I do have an slightly older rev of the board on my github, hope to get it updated soon. github.com/FoxCutter/Tools/tree/master/486%20Breakout I should also add some more documentation on how it should be used with a DX2 and possibly DX4 board.
@Fox-Tech Жыл бұрын
a YM2612 Synth with a 468. count me in, i need this
@curiouscomputer Жыл бұрын
Extremamente interessante!!
@marcoguilherme2477 Жыл бұрын
Ive been looking for something like this. Exactly 486.
@Biomancer81 Жыл бұрын
I never thought it would be possible to do this with an Intel processor. It always seemed complicated to me compared to mc68k and simpler processors... fascinating.
@emmanueloverrated Жыл бұрын
Awesome!
@RazorRadios Жыл бұрын
Круто , хорошая идея
@user-fr7yt8xe2w Жыл бұрын
It's absolutely wild to watch someone *manually* interact directly with a CPU!!
@scottwilliams895 Жыл бұрын
I like your fox! 🦊
@scottwilliams895 Жыл бұрын
Thank you!
@Fox-Tech Жыл бұрын
Whoaaaa that's so cool
@toolzshed Жыл бұрын
Thanks for your great sharing. Should we worry about the cooling problem? If not, I'm curious if it is caused by such a low clock frequency or by 486 itself.
@thomaslewis717 Жыл бұрын
Later models of the 486 did need a heat sink, but this one can run without it. And as it, even running at 4mhz for a half an hour or so still leaves the chip itself cool to the touch. That could also be because the pcb has two copper layers which might be helping with some of the heat dissipation. That might change if I ever get it up to the full 25mhz that the chip is capable of, but for the moment it appears just the ceramic provides enough passing cooling.
@Fox-Tech Жыл бұрын
@@Fox-Tech Both you guy and the chip stay cool! :D
@thomaslewis717 Жыл бұрын
Wow! Excellent tutorial - looking forward to the rest of the series. I like the use of 8 wide ribbon cables to simplify connections. I wouldn't think it possible to breadboard a 486 with all those pins, but that's nothing compared to a modern processor like a Core i9 with over 1000 pins. Brings back memories to the early 90s when I upgraded my 386 system which had a separate Cyrix math coprocessor, to a 486DX motherboard. Does Intel still make the 486 or have to buy used/pulls?
@chrisguli2865 Жыл бұрын
Some of the server CPUs get up to 4000-8000 thousand pins. Makes 168 seems easy to mange. :) It looks like the 486 stopping being made about 15 years ago, so doesn't seem like you can get it new. You can find them on ebay, though make sure the pins are in good shape. There does seem to be a lot of new old stock SX chips there as well, but they are mostly QFP and not PGA.
@Fox-Tech Жыл бұрын
About as far as I go with BB based computers is MC68k based beyond that when I go with higher pin count PGA CPU’s I move to wire wrap or PCB’s which is MUCH cheaper than wire wrap & can get good signal integrity.
@perseverance8 Жыл бұрын
I have a 486sx waiting for something just like this. If you are working on making an 8bit bus, it might be worth looking at the z50 or rc2014 buses. The z50 is only a 16bit address bus, but you could still play in the bottom 64k. The extended rc2014 bus has 16bit data and 24bit address, but could be possible to do 8bit/16bit data & 16/24bit addr.
@mabs-O_o Жыл бұрын
Depending on the revision of the SX, the breakout board could work for you. The main issue is the NMI pin was put into a different location (A15) which is used for a FPU related function on the DX, this was changed in the SX2 to put it in the same location (B15) as the DX. As for the bus, my hope is to eventually have a 32-bit RAM bus with an 8-Bit ROM, but I will look into the ones you suggested as well.
@Fox-Tech Жыл бұрын
I don't know if this will help, but Intel made a MUCH smaller version of this CPU in the late 90s. They were used in embedded applications at the time. There was one in my old Lucent Portmaster that was about 1/4 inch on a side. Maybe it's worth hunting one down?
@spelledfunny Жыл бұрын
fascinating considering this piece of hardware can run modern linux and bsd oses
@piecaruso97 Жыл бұрын
nice works
@karvak1492 Жыл бұрын
coooool. Protogens go beep boop
@zilog1 Жыл бұрын
WooHoo!! Now, gimme an Old School Basic and instant startup plz!! :P :P :P
@bugeyedcreepy Жыл бұрын
I'm probably going to go with FORTH instead of basic, as I've already done a full implementation of it for the z80, so I have a lot of stuff already done. Not quite as old school as Basic though.
@Fox-Tech Жыл бұрын
it is good enough that CPU knows bus length. If you're dealing with 8086, you also need to break a word access into to two byte access.
@HuangLuxuan Жыл бұрын
This is so cool!! now, one question for this is that this is a somewhat modern processor for most breadboards (most use a 6502 or maybe 8086) and this does run x64. could you have a breadboard Linux computer? the last time a 486 cpu was supported on linux was four months ago! and maybe in theory you could employ enough breadboards and chips to replicate the hardware of a motherboard so you could put in a video card! besides. a breadboard can do anything a pcb can do but only bigger! it would be so cool seeing that happen! but I feel like it would be unlikely as it could take too much time.
@le9038 Жыл бұрын
and yes, linux did actually support this for that long. long enough for this to possibly run on a breadboard. kzhead.info/sun/gJh-gLyvjIhplIk/bejne.html
@le9038 Жыл бұрын
Where did you get the LED strips the you plugged into the breadboard?
@TheSlinger1010 Жыл бұрын
Made those myself actually. Was my first real attempt with doing anything with SMD, and they have turned out fairly well. Down side is they don't fit every breadboard, as ones with split rails don't have the holes alright with the board.
@Fox-Tech Жыл бұрын
breadboards are called breadboards because before modern breadboards existed, they would drive screws or nails into wooden boards used to cut bread on
@christiankm8820 Жыл бұрын
Really cool, I plan to follow you now! Do you plan to release schematics?
@alessandro_fasan Жыл бұрын
It's on my github github.com/FoxCutter/Tools/tree/master/486%20Breakout I did update it the most recent version (though a V3 looks likely), and added some notes to it. I will probably move it, along with everything else, to it's own Repo in the near future.
@Fox-Tech Жыл бұрын
Love it, liked and subscribed. One question though, why can’t we use a manual clock?
@abilmansurzhuvandykov9981 Жыл бұрын
It seems like if the clock is unstable (so the high and low times are different) it goes into a shutdown mode. Probably to prevent corruption in the case of low power.
@Fox-Tech Жыл бұрын
@@Fox-Tech thanks, please keep the series going🙏
@abilmansurzhuvandykov9981 Жыл бұрын
Excellent! Subscribed. I've wanted to do something very similar for a while - only with a 80286, not a 486. Maybe this will give me the motivation to actually start doing it. :)
@stamasd8500 Жыл бұрын
That would be cool. The 286 had some interesting packaging, so could make a custom PCB interesting to work on.
@Fox-Tech Жыл бұрын
@@Fox-Tech Ah, nothing crazy (no CLCC sockets etc) just a regular PLCC68 one. I've always been fascinated by the 286 as it was my "holy grail" back in the day. Yeah that shows how old I am. :) The little brain dead chip that could. I even started writing a little protected mode OS for it sometime in the late 1980s, that got nowhere though and I don't think I have that code anymore.I actually have a whole pile of 286s because one day a few years ago I went crazy on ebay and got a lot of 200+ of them(the Siemens 10MHz variant) and want to see if I can make them do something useful, akin to microcontrollers maybe.
@stamasd8500 Жыл бұрын
@@stamasd8500 Cool, hope you can do something with them! I do have some OS code laying around as it's one of my other projects, so I might adapt it to run on the hardware once I have more of it up and running.
@Fox-Tech Жыл бұрын
The Cyrix 486SLC uses the same pinout as a 386SX. I think 386SX and 286 surface mount had the same pinout. Same 16 bit databus I know.
@njspencer79 Жыл бұрын
pretty cool.. but i personally would break it out as a standard PC-104 board.... the reason being there are plenty of peripherals and other stuff that is designed perfectly for something like this. in fact you can still buy (if you're lucky) pc104 386 and 486 and lower end pentium boards.
@WX4CB Жыл бұрын
Nice...
@Hasse.Andersson Жыл бұрын
Wow, 32 bits is kind of painful from an 8 bit perspective. One question, how much current does it pull as those super low clocks?
@paulstubbs7678 Жыл бұрын
I don't know, I haven't thought to check to see what it is. I'll see what I can do.
@Fox-Tech Жыл бұрын
The proper way to introduce the 486 is "The DooM CPU." BRB, going to go invent high-speed solderless prototyping, so this guy can build this thing and go full speed. To play DooM of course.
@aut0turret Жыл бұрын
hey where on earth do you find 8 wide dupont leads? i can find buspirate cables till the cows come home just never any 8 wide to 8 wide connectors. great video by the way never have seen a i486 up close like this excellent work
@el7440 Жыл бұрын
I kind of cheat to get the cables. I get the normal pack of single wide connectors, pull the headers off and then put them into 8 wide headers. It's not perfect, but it works for the most part.
@Fox-Tech Жыл бұрын
I find this quite interesting. Is there a socket under the chip? If not, why not a socket 5?
@drrenard1277 Жыл бұрын
Yeah, there's a socket under there.
@Fox-Tech Жыл бұрын
@FoxTech ok that's good. Just was expecting a zif lever but didn't want to assume. I actually love this and was an idea I've been thinking about doing.
@drrenard1277 Жыл бұрын
@@drrenard1277 I would love to have a ZIF socket, but they cost a lot more then I was willing to pay. That being said, I did try to size the placement of everything on the board so there would be room for a zif socket (based on the measures I could find for one). The socket also let me stick a few decoupling capacitors under the chip, which was a good place for them. Though I think the next rev will use SMD just for the clearance on them.
@Fox-Tech Жыл бұрын
@@Fox-Tech I'm definitely watching you on this. Can't wait to see more
@drrenard1277 Жыл бұрын
Nice, I would like to make sth similar for 386 or other
Awesome, it is nice seeing someone who mutters to themselves like I do. People often remind me of that. I am building a computer processor entirely out of transistors made from 2N2222 transistors. It is fun for me. Keep being you no matter what, you are a gift to the maker community. Many makers end up with so many projects they never fully complete one.
Custom CPUs are always amazing to see, and doing it with transistors seems that much more challenging, which is awesome. And thank you for your kind words!
I am right now Developing a full 1970s era Supercomputer from only NAND gates (mostly because cheap) and its a really challenging task. i also have a upcomming project to make a Computer/CPU from transistors only. i am really facinated by everything logic, and its so cool to have your own computing things...
Pretty cool! I'd like to know how it goes. My only question is how many kilowatts is that CPU going to consume?
@@MK-ge2mh I will post Videos about it on my KZhead channel... but also, it wont consume much power because Cmos logic is quite efficient...
@@curiouscomputer I'll be sure to watch your videos. I thought I was replying to the original commenter saying he was building a CPU out of discrete bipolar transistors. Now THAT'S going to use a LOT of power!
Compared to the clean-cut high production value I'm used to on KZhead, the raw footage here shocked me with how much it felt like I was watching myself Quickest 20 minutes on KZhead!
This is to my knowledge the first series about making a "breadboard" 486 computer. I've searched before but i never found any. Somehow i got recomended this and im very happy. I also have a 486 that i want to make a computer out of but I plan buffering the address and data bus with octal bus transceivers(I dont want to damage the cpu).I also plan to use an arduino or something else for clock,reset and other misc stuff its more easy and convenient(like have the arduino be controlled by serial)
Fascinating project! I've seen my fair share of vintage motherboard repair videos, but it's not often I see someone experimenting with a 486 like this, let alone designing a breakout board to do so! Wishing you the best on this project, can't wait to follow along.
Ikr
I’m not sure they exist for 486, but for the older 386 and 286, there were several CMOS "static core" variants produced for embedded purposes, allowing you to run the clock at whatever rate you wanted, even stopping the clock completely without losing state. Some examples are Intel’s 386EX and the Harris CS80C286. Many CPUs of the era used dynamic memory for internal registers to save die space, and slowing the clock too far results in them not being refreshed frequently enough. It may be able to run very slow for now, but if you start trying to use the internal caches, the MMU, etc., fun errors might start happening :). Assuming you weren’t already alluding to it with your mention of the debounced switches, you can always go for the "button that asserts ready for a single bus cycle" trick. Edit: supposedly the Cyrix Cx486DX was a static core design.
Also the TI and CX SLCs DLCs apparently are static.
Keep doing what you're doing. The world needs minds like yours. Cheers.
Awesome! An idea came to my mind: adding status LEDs to the buses directly on the board would look great, but also could could double as a test bench for the CPU, for diagnosing ones taken from retrocomputers.
I've played around with that, and now that I'm more comfortable with SMDs it would be easier. There is a limited amount of space as the board is 100x100mm and 4 layers, anything bigger then that has a huge jump in price.
Wow! I did not know the 486 could be run at such low clock speeds. I'm studying to start working on something like this myself. Every 486 datasheet I've ever seen specifies the minimum clock speed as 8MHz. Being able to run it as this speed would make things a lot easier in the early debugging stages.
I wasn't sure it would work myself, but being that it's a CMOS chip it seemed like it should work that slow. It's still possible there might be other issues in the future, but it's been fairly stable in my testing so far.
@Lurch Manually running the clock only sort of works, at least for a dozen cycles or so. After that it seems like if the duty cycles are far enough out of sync it goes into shutdown mode until it gets a stable clock again.
The 486 does have an internal 8 KiB 1st level cache. I don't know if it needs to be refreshed all the time but if that is a requirement, than it would definitely limit the minimum clock speed.
@@OpenGL4ever I believe the cache is sram, though as I've yet to enable it yet, I can't say for sure.
Dude this is amazing! Somewhere I've got the 486 processor from my family's first computer in the early 90s. I was allowed to take the computer apart once we upgraded, and I knew that the processor was where the magic happened, although I had no idea how. But I kept the processor, even though I was like 7 years old, and I'm pretty sure it's still in my collection. As I got into robotics with the Basic Stamp 2 and started to look for more powerful controllers, I always wanted to put the 486 into a project, but it was entirely inaccessible to my 12 year old self, both intellectually and on a hardware level. It's super cool to see a breakout for this old processor! You broke one of the main barriers to accessibility. Can't wait to see what you make out of this! Instant sub.
My first CPU is AMD 486 DX2... I used it for maybe 5 years before broken. I salvaged the keyboard, Hard Drive and the CD-ROM but I didn't bother with everything else... I kinda regret it...
Basic Stamp 2 and LEGO Mindstorms is also what got me into computing. My Boe-Bot was one of my most treasured Christmas gifts as a kid.
Wow! I am absolutely living for this! I’ve long wondered what kind of homebrew type stuff could be done with the venerable i486. Can’t wait to see more! Gonna be absolutely glued to this channel!!
This reminds me of an idea I had for repurposing older but functional CPUs: turning them effectively into some sort of microcontroller board, like an Arduino. Obviously they would be a bit bigger BUT they could be standardized.
Very cool project! I love it! Keep up the good work. I'm really excited to see more!
I cant wait to see your next video. I really like the design of your 486 breakout board.
This is ridiculous and beautiful and interesting. I love the concept, the content, and the style. Subscribed.
I really Love having found you, you are extremely smart, and even though the video is kinda slow pace for todays youtube standarts it was extremely satisfying to watch and i really enjoyed it a lot. id love to see more of your content
Really nice to see people push the limits of breadboard computers beyond typical 8-bit DIP CPUs. This project looks amazing and made me an instant subscriber. Hopefully, in the not-too-distant future, this will inspire someone to go even further and make a breadboard computer using a contemporary CPU. Even a brand new Celeron would be incredible to see. Still, your work with the 486 is amazing and deserves far more attention.
Thanks for making this video. I'm glad it's not just me who mutters along to myself while working. You can always cut/ speed up sections of putting wires in if it's more comfortable. Great level of detail as well. It's easy to go too simple or too complex
Amazing project! I'd love to see where this goes in the future
that's very clever indeed! Thank you for your demo!
This is unspeakably neat; thank you for doing this and sharing it with us.
I remember back like 2004/5 in high school some friends and I were all in agreement that like, 386s and 486s are far too complicated for a homebuilder to ever build their own computer around. Granted that was in the days before easily designable and quickly available custom multilayer boards. But it's an assumption I'd been second guessing lately, so seeing this is extremely cool. Very nice work.
At this point I believe the Pentium / Socket 7 systems are the "very difficult" point. The bus protocol was never officially public, although the AMD K6-2 manuals have a very good description of the bus timing. It’s a synchronous bus so timing becomes a difficult problem. Totally solvable using FPGAs, but the signal count is high (like 250), so you’ll have to use a BGA variant.
Excellent project and rundown.
Really nice Project, looking forward to the next episodes :) First time I got the idea of a the 486 as a managable processor and how it operates, havent looked into it very much before, but inspires to learn more about it. Keep it up, especially with the awesome one take :D
This is awesome. the 486dx was the processor I first came in contact with.
"A full breadboard computer with a 486." Ambitious! Nice. :) It's really interesting to see how the 486 connects up to everything. Nice to know it can run at much lower clock speeds than advertised.
This is so amazing. Keep up the good work!
This should be a fun project! Good luck with it!
Nice video i enjoyed it alot. Super impressive 🎉
we NEED Ben Eater here, right now.
Didn’t realize I had a DREAM KZhead collaboration - but there it is!
Soon: The most over-engineered calculator, ever!
You sell the boards and I'll be your first customer!
"The standard NOP... So yeah we're just going to start telling it do do nothing and if everything works it should do nothing. but it's the nothing that we are telling it to do. which is better than the nothing we're not telling it to do. That made more sense in my head." - Dude, that is hilarious. I want it on a T-Shirt just to make the 99.9999 % of the world say , "WTF does that mean?" It only makes in the heads of those who are fascinated by this kind of stuff. A very small club indead (I am a member of said club ) Carry on !! Cheers
Even though it's doing nothing, it's doing something.
So awesome… well done!
My first PC ever had a 486DX in it.. apart from this video being purely awesome, it also made me feel really nostalgic
Love it! What a great project!
Awesome project!
I can't wait to se this evolve. I'm currently playing with a Z80 just to get me started. Uncut and honest video, i like that format :)
Thank you, I'm glad you enjoyed it! The format is inspired by a few other creators I follow, especially @weirdboyjim . I will probably be having some edits for timelapse in the future, or to cover problems with my current setup, but not to remove any content. Seeing the mistakes are half the fun for this sort of project.
@@Fox-Tech Time lapse for certain parts is not a bad idea :) I was curius about doing something with an x86 but when I read that the minimum frequency was in the MHz range i hesitated. Seeing that you can i fact run them in the KHz range inspire me to build something. Can't wait for you next episode in the 486DX series :D
I would love to see the next video on this is awesome. I miss my 486. Also new Subscriber.
Fantastic project and a great learing tool, well done - package it and sell it!
Thank you!
Damn. 486DX was my first PC at home. Didn’t expect to see it on a breakout board…
Love the concept of this. Watching to see how far you can go with off the shelf modern parts. Could be a way to have a nice PCI setup as the 486 PCI boards are either really bad or extremely rare and expensive.
PCI is way more involved than what's needed for a bit of RAM and ROM. My EE course where we did microprocessor interfacing we just did PC bus (as in original 8086->style) which is simple enough to do with simple gates and latches. For PCI you need a fairly complicated state machine, especially for the discovery and initializing.
It's pretty cool. Hope down the road you can add a simple video card and sound card. Wish I knew how to build stuff like this.
This is really cool! As someone with a passing interest in this type of old computer some of this flies over my head but it looks like a fun concept. One thing I would suggest is maybe adding a socket to the breakout board so you could use other 486 chips from like AMD or CyrIx
There is a socket under the chip, but it's a standard pin socket and not a ZIF socket (which are much harder to find, might see if I can scavenge them from old motherboards in the future) so it's not really visible.
I hove we see new series soon, its so interesting. Subscribing now
This is a very cool project. However, I strongly recommend that you seriously consider increasing the number of ground connections. You don't appear to have any on to the board apart from the power connection. With wide busses, it will become very important that the ground for the signals doesn't bounce around when the signals switch. Even if you are only clocking at (say) 100kHz, the signals still transition between high and low logic states at the same speed as if you are running at full speed. The rapid simultaneous charge or discharge of multiple signal lines causes noise spikes in the local signal ground, which affects how other devices see the signals. (Research ground bounce for more info.) I'd recommend one or two grounds for every eight data or address lines, and more grounds where you are grouping control signals. While things may work OK reading static instructions from switches, it will very quickly get hard to debug unless you can keep the signals free of too much noise. This will only get harder with a breadboard compared to a good PCB design.
Thank you. That's very good to know, I will research that and try to improve things. Right now the board does have a layer that's just ground plane, I don't know if that will help any in this case. Still, I will be looking into that and trying to apply it on future PCBs.
@@Fox-Tech Certainly a ground plane is a good idea, but you also need to minimise the ground impedances between CPU and each area of the design that it's connected to such as the data buffers that you added, clock sources, decoders, anything driven by the address lines, and so on. Ideally, as well as the ground from the power supply, you will have direct ground paths from CPU to each other section, and they will also have their own ground connections back to the power supply as well. One of the difficulties is that the ground voltage spikes caused by fast ground current transients can be extremely short and very localised making them hard to measure. (Q... when is zero ohms not zero? A... When it's a 50 nano-Henries of inductance and the current spikes from 2mA to 100mA and back in less than 10 nano-seconds.) This all leads to the issue that each chip will see the same signal differently, based on it's local ground (at the chip inside the package) and that will be somewhere that you cannot measure even with a decent oscilloscope. This is why it's better to design high speed digital circuits with an over abundance of caution regarding signal grounds, rather than trying to fix the problem afterwards. But don't be discouraged. With the right research (which you've already demonstrated in terms of how the 80486 talks to the data-bus, for example, this could become a very interesting and rewarding project. I am watching with interest and admiration. (I have designed plenty of fast complex logic, PCBs, etc, but never around a 486 - and I have a DX33 in my junk box somewhere...)
Good lord, what a project for a KZhead debut 😂🎉
ok, I'm already excited for the next part
Subscribed for this, just wow!
It's funny that although tech has evolved (boomed) so much in the last 100 years or so, and there are things that are way faster and more efficient than this aging 486, yet I'm still finding it insanely cool to look at old tech, especially when a "modern twist" is added to them. Very very cool board, now please add a screen and run Doom on it.
This is truly FUN 😀 My bet you have started a whole new trend. Now to integrate it into the Arduino world - then you will suddenly get support as you never dreamed of ... I just sub'ed as I find this project very interesting indeed !
Very interested to see how this will turn out.
Shut up and take my money.... seriously love the project
i'd been curious to try something like this myself if i had some old processors to mess with. Would be fun to turn one of those old cpus into an impractical microcontroller or something.
omg you totally rock for this pal!!! :-D
The split into separate code address space and data address space was also available on the Motorola 68000 series as well, I think starting with the 68020. I hadn't heard of any 68K systems that actually used that feature either. In theory it could allow for better code security by locking out modifications to running code. It might also make it easier to map in ROMs without having to carve out a block of the address space.
Cool project :)
This video is triggering my interests so dang much!!! I’m loving every bit of it! (Pun intended) I’ll be watching the next 2 parts now. :)
This es REALLY INTERESTING 😮😮😊😊 !!
I used to design Intel based systems i386DX ,i486,i960 ,i860 .All had similar buses and needed epld 10 ns ( very fast back then ) to latch some of the bus control signal .The code was given by Intel in the hardware manual .
Oh, that's cool. Feel free to tell me when I'm doing something completely wrong then! Actually, I think I ran into some of that code in question today, while looking for something else.
Hey this is cool! Back in 05 I designed and build a computer using an 8085. I always thought it would be cool to make one based off the 68020, but that's a lot of wire wrapping! I'm subscribing to follow along!
Honestly, ordering custom PCBs is so cheap these days that I have become lazy and go for a PCB first … problem is what to do with the other PCBs I didn’t use because most of my projects are one-offs and you get a minimum of 5…
@@teknoman117 I would do the same. It's just that every time I sit down with the software It feels like there is a large learning curve. I got enough going on without having to take the time to learn it.
next video - Cray YMP on a breadboard :D impressive, seems like a fun project you have gotten yourself into!. I like it.
I like it! Just today i ordered a PCB what extract the pinout of a 186 to a ISA Bus (for sure with custom pinout, but useable on a standard backplane). I want to do the same "Selfmade Computer" with it. The 186 uses A0 and BHE to seperate the lower and higher Byte of the 16bit Data. And yes, you can mirror/overlap a single memory Chip/adress space to two different locations 😅 Its nice to know that the 486 can work with 8bit components. And one of my first tests will be the lowest working frequency because i want to see blinking LEDs too
That sounds like fun. I don't think the 186 gets used enough, so glad to see someone doing something with it! In 16-bit bus mode, the 486 has the same A0/BLE BHE signals. That's one of thing that seems consistent throughout all revs of the CPU.
@@Fox-Tech There are some DIY with the 80186/88 in the WW - but just a very few. Most of them are SBCs copied from very old schematics or pc-magazines. I want to start from scratch with something like a computer and not PC/Amiga or somthing compatible.
nice video thanks
Oh that's really cool.
I'm looking forward to the next episodes of this :) Also: I'm wrecking my brain on how to connect a single 8bit RAM to all four parts of the data bus. I guess I'd aim at 4 switchable bus tranceivers (74xx245?) connected to the byte enable lines and a 4xOR from all byte enables to the /CS of the RAM...
That's pretty close to what I'll be doing, though using a 74139 to select enable the chip.
You'd be far better off racking your brain since that is the correct English idiom!
I am interested to see where this goes (and yea its similar to most processors, but its still interesting as most people wont go past dip packaged chips)
I could be mistaken, but as I gather, the 486 was pretty much the last of the "similar to other processors" before things like low voltage levels and specialized busses became a thing. The beginning of that trend is touched-on, here, in that even though you can tell the 486 to access individual bytes, it expects them on different data-bits depending on their alignment. Not difficult to do with TTL, but not "easy", either. (imagine its being connected to an 8bit ISA card!). So, at some point it became almost essential to have bridge chips to interface with the outside world, even if that's nothing more than a boot ROM. So, in a lot of ways the 486 is maybe amongst the last of the "similar" CPUs (Z80, 6800, even 8088) (and comparatively *really powerful*) that folk like us *can* "breadboard". That was a very exciting finding...
Oh wow, this is neat! I had no idea you could interact with an intel CPU like this without having a full PCI bus, north/south bridge, memory channels etc. It will be super interesting to see how far you’re able to get, eg if you write your own simple BIOS etc. Nice work man 👏
Actually, a simple BIOS is in the cards, might be FORTH based just because I happen to like that language. :)
I really like the idea and your presentation! A friend gifted me a beautiful 33MHz 486 a while ago, but I haven't had a way to use it yet. I wanted to make a board like this, but the datasheet seemed a bit too complex for a weekend project. Are you planning to share the board design? I'd even like to use this in my own YM2612 retro synthesizer design.
I'm glad you like it. I wasn't sure of exactly how to handle this, and tried a few different things before settling on this one. I do have an slightly older rev of the board on my github, hope to get it updated soon. github.com/FoxCutter/Tools/tree/master/486%20Breakout I should also add some more documentation on how it should be used with a DX2 and possibly DX4 board.
a YM2612 Synth with a 468. count me in, i need this
Extremamente interessante!!
Ive been looking for something like this. Exactly 486.
I never thought it would be possible to do this with an Intel processor. It always seemed complicated to me compared to mc68k and simpler processors... fascinating.
Awesome!
Круто , хорошая идея
It's absolutely wild to watch someone *manually* interact directly with a CPU!!
I like your fox! 🦊
Thank you!
Whoaaaa that's so cool
Thanks for your great sharing. Should we worry about the cooling problem? If not, I'm curious if it is caused by such a low clock frequency or by 486 itself.
Later models of the 486 did need a heat sink, but this one can run without it. And as it, even running at 4mhz for a half an hour or so still leaves the chip itself cool to the touch. That could also be because the pcb has two copper layers which might be helping with some of the heat dissipation. That might change if I ever get it up to the full 25mhz that the chip is capable of, but for the moment it appears just the ceramic provides enough passing cooling.
@@Fox-Tech Both you guy and the chip stay cool! :D
Wow! Excellent tutorial - looking forward to the rest of the series. I like the use of 8 wide ribbon cables to simplify connections. I wouldn't think it possible to breadboard a 486 with all those pins, but that's nothing compared to a modern processor like a Core i9 with over 1000 pins. Brings back memories to the early 90s when I upgraded my 386 system which had a separate Cyrix math coprocessor, to a 486DX motherboard. Does Intel still make the 486 or have to buy used/pulls?
Some of the server CPUs get up to 4000-8000 thousand pins. Makes 168 seems easy to mange. :) It looks like the 486 stopping being made about 15 years ago, so doesn't seem like you can get it new. You can find them on ebay, though make sure the pins are in good shape. There does seem to be a lot of new old stock SX chips there as well, but they are mostly QFP and not PGA.
About as far as I go with BB based computers is MC68k based beyond that when I go with higher pin count PGA CPU’s I move to wire wrap or PCB’s which is MUCH cheaper than wire wrap & can get good signal integrity.
I have a 486sx waiting for something just like this. If you are working on making an 8bit bus, it might be worth looking at the z50 or rc2014 buses. The z50 is only a 16bit address bus, but you could still play in the bottom 64k. The extended rc2014 bus has 16bit data and 24bit address, but could be possible to do 8bit/16bit data & 16/24bit addr.
Depending on the revision of the SX, the breakout board could work for you. The main issue is the NMI pin was put into a different location (A15) which is used for a FPU related function on the DX, this was changed in the SX2 to put it in the same location (B15) as the DX. As for the bus, my hope is to eventually have a 32-bit RAM bus with an 8-Bit ROM, but I will look into the ones you suggested as well.
I don't know if this will help, but Intel made a MUCH smaller version of this CPU in the late 90s. They were used in embedded applications at the time. There was one in my old Lucent Portmaster that was about 1/4 inch on a side. Maybe it's worth hunting one down?
fascinating considering this piece of hardware can run modern linux and bsd oses
nice works
coooool. Protogens go beep boop
WooHoo!! Now, gimme an Old School Basic and instant startup plz!! :P :P :P
I'm probably going to go with FORTH instead of basic, as I've already done a full implementation of it for the z80, so I have a lot of stuff already done. Not quite as old school as Basic though.
it is good enough that CPU knows bus length. If you're dealing with 8086, you also need to break a word access into to two byte access.
This is so cool!! now, one question for this is that this is a somewhat modern processor for most breadboards (most use a 6502 or maybe 8086) and this does run x64. could you have a breadboard Linux computer? the last time a 486 cpu was supported on linux was four months ago! and maybe in theory you could employ enough breadboards and chips to replicate the hardware of a motherboard so you could put in a video card! besides. a breadboard can do anything a pcb can do but only bigger! it would be so cool seeing that happen! but I feel like it would be unlikely as it could take too much time.
and yes, linux did actually support this for that long. long enough for this to possibly run on a breadboard. kzhead.info/sun/gJh-gLyvjIhplIk/bejne.html
Where did you get the LED strips the you plugged into the breadboard?
Made those myself actually. Was my first real attempt with doing anything with SMD, and they have turned out fairly well. Down side is they don't fit every breadboard, as ones with split rails don't have the holes alright with the board.
breadboards are called breadboards because before modern breadboards existed, they would drive screws or nails into wooden boards used to cut bread on
Really cool, I plan to follow you now! Do you plan to release schematics?
It's on my github github.com/FoxCutter/Tools/tree/master/486%20Breakout I did update it the most recent version (though a V3 looks likely), and added some notes to it. I will probably move it, along with everything else, to it's own Repo in the near future.
Love it, liked and subscribed. One question though, why can’t we use a manual clock?
It seems like if the clock is unstable (so the high and low times are different) it goes into a shutdown mode. Probably to prevent corruption in the case of low power.
@@Fox-Tech thanks, please keep the series going🙏
Excellent! Subscribed. I've wanted to do something very similar for a while - only with a 80286, not a 486. Maybe this will give me the motivation to actually start doing it. :)
That would be cool. The 286 had some interesting packaging, so could make a custom PCB interesting to work on.
@@Fox-Tech Ah, nothing crazy (no CLCC sockets etc) just a regular PLCC68 one. I've always been fascinated by the 286 as it was my "holy grail" back in the day. Yeah that shows how old I am. :) The little brain dead chip that could. I even started writing a little protected mode OS for it sometime in the late 1980s, that got nowhere though and I don't think I have that code anymore.I actually have a whole pile of 286s because one day a few years ago I went crazy on ebay and got a lot of 200+ of them(the Siemens 10MHz variant) and want to see if I can make them do something useful, akin to microcontrollers maybe.
@@stamasd8500 Cool, hope you can do something with them! I do have some OS code laying around as it's one of my other projects, so I might adapt it to run on the hardware once I have more of it up and running.
The Cyrix 486SLC uses the same pinout as a 386SX. I think 386SX and 286 surface mount had the same pinout. Same 16 bit databus I know.
pretty cool.. but i personally would break it out as a standard PC-104 board.... the reason being there are plenty of peripherals and other stuff that is designed perfectly for something like this. in fact you can still buy (if you're lucky) pc104 386 and 486 and lower end pentium boards.
Nice...
Wow, 32 bits is kind of painful from an 8 bit perspective. One question, how much current does it pull as those super low clocks?
I don't know, I haven't thought to check to see what it is. I'll see what I can do.
The proper way to introduce the 486 is "The DooM CPU." BRB, going to go invent high-speed solderless prototyping, so this guy can build this thing and go full speed. To play DooM of course.
hey where on earth do you find 8 wide dupont leads? i can find buspirate cables till the cows come home just never any 8 wide to 8 wide connectors. great video by the way never have seen a i486 up close like this excellent work
I kind of cheat to get the cables. I get the normal pack of single wide connectors, pull the headers off and then put them into 8 wide headers. It's not perfect, but it works for the most part.
I find this quite interesting. Is there a socket under the chip? If not, why not a socket 5?
Yeah, there's a socket under there.
@FoxTech ok that's good. Just was expecting a zif lever but didn't want to assume. I actually love this and was an idea I've been thinking about doing.
@@drrenard1277 I would love to have a ZIF socket, but they cost a lot more then I was willing to pay. That being said, I did try to size the placement of everything on the board so there would be room for a zif socket (based on the measures I could find for one). The socket also let me stick a few decoupling capacitors under the chip, which was a good place for them. Though I think the next rev will use SMD just for the clearance on them.
@@Fox-Tech I'm definitely watching you on this. Can't wait to see more
Nice, I would like to make sth similar for 386 or other
PROPER NERD SHIT!, this is amazing!