I just get recommended this video after 4 months of the upload, I'm very upset because I've been looking for this content before, I'm very willing to watch all your videos because nobody has explained this CPU at electrical level, just software and debuggers and things like that. Thank you very much.
Thank you very much for your comment. Out of these 4 months, three were very very slow in terms of growth. Just a month ago I had around 20 (!) subscribers. The more nice comments (like yours) and likes I get, the more often the videos may be recommended to new viewers. So thank you all and stay tuned for the next video.
Thank you very much. I'm really having lots of fun doing this. I'm really happy that somebody may like what I do. Unfortunately, I had to take a break from this during the summer holiday, but the next video should be available in the first half of September.
I wish I had known what I know now and could find these kind of videos when I was learning. Makes a lot of low level stuff very clear. Thank you very much!
Mikey, thanks for stopping by. I'm sure there is many more better videos out there, but if you can spend a moment around here, I'd be more than happy having you around. My only aim for the audience is to have at least a tiny fraction of the fun I have building these contraptions on the breadboard. That's all it is, thank you staying around here!
Technically the NOP opcode (0x90) is for the XCHG AX, AX operation, which would swap the AX with itself (or rather its contents). Whether or not a given x86 CPU actually performs this operation is implementation dependent. It is nice to see the venerable 8088 used in a video like this. Thanks!
Yes, of course, you are right. The encoding of "XCHG with the accumulator" is 10010rrr, where the "rrr" is 000 for the AX. I didn't mention to avoid confusing those who didn't know the platform well. Thank you!
Excellent presentation. I have built my own 8088 system, which implements single step, but I never considered a solution whereby the clock of a CMOS processor could be stopped. You learn something new everyday!
Thank you very much. Yes, the clock of the CMOS version can be arbitrarily slow, but it is true only for the CMOS, which you can tell by the letter "C" between the "80" and "88". The datasheet of the HMOS version says that the maximum clock cycle period is 500ns which translates to 2MHz.
I know this isn't exactly related, but it kinda is. I got a couple interesting brief stories regarding the clock stopping... First situation is rather simple. I used to repair and modify cheap digital watches in my teens, back in the 90s. I discovered quite by accident that if you touched the pins on the quarts crystal oscillator, the display would go blank and the time would get stuck, until you removed your finger anyways. Second story is much more odd though. Once I had an HP laptop come into my computer shop, which was acting rather odd after they had dropped it. Everything appeared to still be working, more or less. But we found viruses on it and chalked the weirdness up to the viruses, so we decided we should reinstall Windows ya know.. This is where things got really weird. As we started reinstalling Windows, it would just randomly lock up, like solid. Well we had many computer repairs at the same time so it sat there like 4 hours stuck, in the middle of XP reinstall. But as soon as I lifted the laptop up, my fingers pressed in a little in the middle to balance it ya know, but when I did the computer suddenly started running again haha! And you could repeat this too, set it back down on the flat desk and it freezes, lift it up by hand and it keeps running right where it left off flawlessly! I dunno what exactly went wrong with that timer circuit, but it was pretty obvious that there was a bad solder connection some damn where. Whatever connection/line broke loose was like a damn pause button for the CPU.
I built a breadboarded 8088 system for my Sr design project in college back in 1988. I still have the project breadboarded but wires came loose and corroded. Looking to reverse engineer and rebuild it so this is good review.
I still have my 8088 system build on a (homemade) PCB 20 years ago. Because of many changes I applied to it later on, the PCB looks really messy and I'm not brave enough to power it on ;-) Thank you for your interest!
Thank you for the perfect information and great explane , my 8088-2 is working perfect now , i made a lot of tests with no result before , but now it works
В 1986 я собрал свой первый контроллер на К1810ВМ86 и DRAM К565РУ5 на 128kb. Использовал при этом проводной монтаж микросхем. In 1986, I assembled my first controller using K1810VM86 and 128kb DRAM K565RU5. I used wired installation of microcircuits.
russian cpus are cool as hell, cpushack introduced me to them and theres just something cool about the white and gold ceramic packaging they use. id love to get my hands on an old russian 8086 machine
I am writing an emulator for the 8088 and there is something really satisfying to thee that my emulator is very accurate compared to real life, I knew it because I read the documentation about a thousand times a carefully implement it, but still, to see it is very satisfying. Nice video and nice subject, I kind of wanted to build my own computer based on an 8086, maybe one of my future projects :)
Thanks for your comment. Of course I'm aware of Ben Eater's videos and I appreciate them a lot. I'm not here to compete with him at all. I just thought that I'd be able to share my experience in programming Intel CPU's while having fun rebuilding a working machine on a breadboard. I must say that Ben's videos kind of inspired me to do what I'm doing here, really. I hope you'll enjoy the rest of the series.
@@SladorSoft Well actually i meant that as complement like expansion/extension/addition to Bean Eater with provide us with more glorious low level nerdy shit i(and people like me) love and enjoy.
Check out James Sharman's 8bit Pipelined CPU. It's excellent; he's designed his own CPU, VGA, Sound, etc., from scratch in 100s of videos. On Breadboard and PCBs. All open source.
Aguardamos o décimo vídeo desta fantástica série de vídeos! E desde já agradeço sua disposição para dividir com todos nós os seus conhecimentos. Muito Obrigado!
Obrigado meu amigo! Next video is almost done - I am struggling with finding enough time to finish it. I have plans for at least 3 more videos in this series after which I'm going to design a new, hopefully final PCB for this computer.
вау, я никогда не думал что такое может быть очень интерестным, я правда не разбираюсь в программировании(к тому же старом, я об asembler) я только могу собрать копьютер кому нибудь, а понять его полностью, и использовать для своих целей, эт мега круто и интерестно. Подключить провода и сделать из него что то своё - взрыв мозга. Автор, большое спасибо за твой труд! Хоть тебя и смотрит определённо малая аудитория, но это правда очень интерестно и ценно для меня и остальных, мне даже книгу никакую не пришлось читать)) p.s. ты хорошо обьясняешь
Videolarınız âdeta biler kütüphane değerinde, Şimdiye kadar daha sade bir anlatıma henüz karşılaşmamıştım, Bu sebeple bilgisayarıma arşiv olarak indirmiş bulundum, Türküye den Selamlar
@@SladorSoft inspired by this video, i got a mindset it is feasable to build a minimal system..I made a PCB together with some logic and got my own system running now
Intel 808x CPU supports >1MB by design, 1MB is IBM PC limitation. In every memory cycle 808x outputs 4 status bits on the pins which can be used to separate/extend memory segments for code, data and so on.
Oh that's beautiful. I've looked into the 8088/8086 in the past for potentially using in a homebrew computer, but the multiplexed busses put me off. Also I thought I remember some clock phase requirements, but I might be wrong. Didn't know there's a static version either, nice. I still prefer the motorola 68000, but it would be interesting to give the 8088 a try at some point; should be fun. Subscribed to remember to watch the rest of your videos about it.
I've recently gotten into assembly by writing a fibonacci sequence program that takes command line arguments on Linux. It was a neat project, and definitely taught me about how x86 assembly works, but I'm not sure what my next step should be. Perhaps my solution lies in creating something with an older piece of kit like this one.
I have my original 8088 (IBM PC) and also an NEC V20 that someone gave me which is compatible but a little faster on some opcodes. I just checked for 80C88 to follow along but they are out of stock. I'm also watching John's Basement where he explains the pins for the Z80 so it's cool to see what is the same and what's different.
Hi there. Yes, I'm aware of the fact that it's quite tricky to buy 80C88. In part 7 I introduced the 80C188 which is much easier to find on eBay or AliExpress.
Well done! You just did what I did at school in 1984 😁 OK, your manual Clock circuit is better/more precise! Needles to say, I instantly subscribed to your channel 👍
Amazing man I building something like this but it achieves 16bit by running two 8bit processors into each other. (I call it a 8x2 computer because it's not 16 bit technically)
Ben Eater ++ .... great project ! TY!! new sub indeed :) a great explaination of the clock diagram ever seen. congraats! very well done. who can't thumbs up this video?? :)
It's an electrical question about the resistors. How does putting a resistor between, achieves its "state" (1 or 0, or Voltage or ground) to be recognized only as data (when the CPU reads from "memory"), and not as an address as well (when the CPU requests what address to read data from)? PS: I have been a software developer for many years, but I don't know that much from the electrical side of things.
Hi! The AD0 - AD7 pins are bi-directional. It means that they are sometimes outputs, when the CPU asserts the address bits (when the ALE is active) or when it writes data to memory, or inputs, when the CPU reads data from the data bus. In the latter case, those pins have very high impedance and therefore can be driven by the resistors from either 0V or 5V. When they become outputs, the CPU is driving them instead, setting the required voltages. The resistance of the resistors is high enough (a few kOhm) for the CPU to override the voltage level of the pins. If the resistance was too small, we could damage the CPU as the current flowing from the CPU through them would be to big for the circuitry of the CPU to handle. This above is also correct in all other similar cases as well, but the 8088 has in fact a special circuitry on those pins which determines the upper resistance value for those resistors. These pins need to be driven with at least 400uA to be correctly set to a logical level. That means that the resistors' values could not be greater than 5V / 400uA = 12.5kOhm. I hope that makes sense (without drawing example schematics).
@JoseGustavoAbreuMurta - Wow! These are really cool! I've not seen them before. Had I seen them when I was starting this series, I'd definitely use them. These days though I'm not really relying on looking at the buses anymore while making my videos, but thanks again for your great idea.
fantastic work, thank you for creating this. in your videos, you refer to 74hct logic, but in your schematics, 74hc logic. does it make any difference for the 80c88 or V20 chips?
Thanks Graeme! Yes, that's a fair point. In this case there is no difference between HC and HCT, so I used the general HC family in the schematics, but I had some HCTs in my drawer, so I had used them in the videos. The difference is important only when you mix these with the LS series chips which have different voltage levels for both 0 and 1. I tried to explain that in the other video: ua-cam.com/video/7_hZLauyYRg/v-deo.html
I am planning to put together a simple website where I would publish all schematics, source code and other details for reference. Currently I'm focused exclusively on publishing the next video (which should happen finally this weekend), but after that I'll think about this website. I'd like to ask for a little patience as this is my after-hours project and initially didn't expect to get this interest honestly. As to the values, I assume you ask for these in the clock circuit (around the button). I used some common sense arbitrary values: R around 10k and C around 10uF. The resistors on the data bus in the 1st video were around 2.2k.
my high school dream is using computer processor to make video game.. i did use 8088 processor to build LCD game.. i think video game thr graphics controller is most complicated then processor.. recently im thinking using 8751 as video game processor bcoz i like yhe ceramic with quartz window able to see the chip ..
That's interesting, but personally I'm a little bit too lazy to use anything involving EPROM these days (not that I didn't use it back in the past), especially when trying to fix a problem by re-flashing and testing several times in a loop. But if you follow this series, I can promise that I will be going towards building a full-featured computer and write a video game for it.
@@SladorSoft That will be nice.i will check your video later again and follow up.. yes agree to re program EPROM is troublesome. but if can try in Flash memory like 28C64 or something then once the firmware work then will program in 2764 or something.. make the RAM large enough so all the software store in SD card using SPI.. i did successfully write in 8051 assembly code to access SD card under 2GB , FAT16 once the firmware work well everything will pass down to SD card like harddisk.. the only thing 8751 dont have Ready and hold pin for DMA..etc i still not sure is it possible to modify by stop clocking the process to let it access the data bus. For video game project i still not fullty understand how the NES or SNES system work.. i think the most complicated will be the Graphics portion which can handler spirit and front moving object..
I have already recorded the next video - now I'm in process of editing and creating the "graphics" covering my commentary. Thank you for watching and your patience ;-)
The RESET is active HIGH. Also, it needs to be HIGH at least 4 cycles to reset the processor. As soon as it changes to LOW, it initialises itself for approximately 7 cycles after which the CPU starts fetching and executing the programme. For normal operation RESET needs to stay LOW at all times. The first 7 cycles is just the initialisation of its internal state before normal operation. Hope that clears this a little bit.
no clue if this will be seen or not but does any place have a bill of materials of what chips and other items that are used in this project? I know there are schematics on the page, but looking for a shopping list I guess :)
Of course it will be seen ;-) I read all the comments on this channel. You are actually not the first person asking for the BOM, so, if people find it useful, I have decided to put it somewhere on my website: slador.uk/ sooner or later. It will probably not happen this week, as I would like to focus on my next video, but I'll try to make it soon.
Thanks! No, not really. The main reasons are: lack of any kind of a storage device and graphics card - the 20x4 LCD is a little to small to make it a usable "screen". I am considering building a kind of a graphics card device as a future plan at some point though. This series was rather meant to allow me having fun tinkering with the 8088 - not to build a proper computer ;-)
@@SladorSoft You could try emulating an MDA adapter, which would be less difficult since it's text only. Or get data in and out of the computer using a UART and a serial terminal.
Thank you so much! Being helpful in any way is more than I ever expected! Unfortunately, I have no experience with the others in opposite to x86, so probably won't cover them.
Hi @hyblidblackbox8847. I'm not entirely convinced that it is incorrect. It's intention is to show that each segment register can point anywhere in memory and that its segment is 64kB in size. There is no assumptions about where each segment actually is or what order they appear. The only constrain is that after reset, the CS is initialised to 0xFFFF. You said that start and end are switched, but memory maps are usually created from bottom up and this diagram follows this convention. I would defend this diagram even if I wasn't its author. It was taken straight from the CPU datasheet. Funny thing is that it does have a mistake after all, which nobody pointed out: the size of the CS segment is labelled as "64k-bit" when it should read "64k-BYTE" ;-)
@hyblidblackbox8847 - no reason to apologise. Any input is welcome. Our comments here could also be useful for others interested in the x86 architecture. Thanks for that!
Thank you for this series of videos. I have a question. I follow the same steps you follow to get the FFFF0H but I get a FFFFFH. What could be happening?
Hi @cesarari007. It is really hard to answer your question, without looking into your contraption and taking some measurements. The reason could be anything like faulty CPU, mistake in wiring, reset signal not applied (or not removed when it should be), incorrect supply voltage and so on. I would start from making sure that your clock and reset signals changes as you expect them to. Again, the "reset" must be held active for at least 4 clock cycles, then it needs to go to "0" and after 7 more clock cycles the FFFF0H should appear on the address lines. Putting LEDs in both the clock and reset lines should help visualise their levels. I'm sorry that I cannot give you more specific advice.
@mihirsevak4456: the schematic is shown in the video around 12:14 timestamp (the circuit you're asking for is in the bottom-left part). It is also available on my GitHub: github.com/sladorsoft/Intel8088OnBreadboard I used 74HCT14 and 74HCT74. The couple of the pull-up resistors are around 10k and the caps are 1uF
@malikahmed49 - thanks for having a look. My idea in this series was to show and talk about every chip I add to the contraption. Also, when I make changes I always show the schematics with all the elements used at the moment. I was hoping that it was enough to replicate the contraptions. Have a look at my GitHub where I added all the schematics for every video. They are in two formats: the native KiCad and the PDF, if you don't have (or want) the KiCad installed.
I'm excited as well, Alexander, believe me . The whole YT thing is all new to me as well and honestly, until the latest moment, I cannot tell if the script I planned would work as expected. I try to be honest when I record these and if something does not work as I planned, I am going to state that clearly. So far, so good!
That's a really interesting question. I assume that you are asking about building the computer from scratch (like I do in these videos). First of all: it is not possible to run Windows 3.11 on either 8088(6) or 80188(6) as it uses the CPU's protected mode. It can run on at least 80286 in so-called "standard mode" or 80386 in the "enhanced mode". Despite Windows 3.11 being a 16-bit OS, the "enhanced mode" is particularly interesting, because - which is not immediately obvious - Windows itself is one of the virtual machines running by a 32-bit (!) hypervisor. Then, any MS-DOS processes started under Windows run each in a separate, additional VM running in the CPU's "virtual 8086 mode". I think it's quite interesting, in technical terms, because most people would assume that Win 3.x were only a "shell" running on top of MS-DOS, while it was so much more under the hood. After this long introduction, let me finally answer your question. You need at least 80286 CPU, at least 1MB of memory, VGA controller, keyboard and serial port (for serial mouse) controllers, some storage and a controller chip for that - shortly speaking - quite a lot. And I haven't yet mentioned lots of logic chips gluing everything together. And all of it would probably need to be IBM-PC compatible, so the controllers would need to have standard I/O ports and memory locations. To simplify my 80188 computer I decided not to follow the IBM-PC compatibility (not to say that you would not be able to run Win 3.x on it anyway), but I hope it will be able to run some of these: FreeDOS, MS-DOS or elks at some point.
@@SladorSoft right now I have thoes chips I’m gonna get 1pcs 82C450 1MEGABIT Dram VGA Graphics Controller Sis FT232RL FTDI Module USB to Serial for Arduino Mini USB to 232 FT232 USB to TTLMiNi ENC28J60 Ethernet LAN Network Module For Arduino SPI AVR PIC LPC STM32Macronix MX29F1615PC-10 MX29F1615 16MBIT FLASH EEPROM PDIP40 X 2pcs PIC18F4620-I/P PIC Microchip microcontroller 40MHz Flash 50 MHZ Full Can Footprint Dip14 3V3-5V Crystal Oscillator maybe we can work together and our brains can make this seemingly impossible project real or as real as we can get with breadboards lol
@@SladorSoft also another thing I didn't mention I know it may be really complex in a lot of components and I expected that maybe we can help each other by creating a list of what exactly we need to do and possibly collaborate and make it possible or attempt to at least I mean it may take awhile for me to get the parts being jobless and all but still a good idea nonetheless
Hi @yuriiradkovskyi8330. I have no experience with the V20, but I'm afraid that the manual clock may be impossible (despite that it's CMOS as you pointed out). According to its datasheet the maximum allowed clock cycle is 500ns, which translates to the minimum frequency of 2MHz.
Hey there! I'm thinking of starting this project. Where will I get the ic? May I know where you get your parts. I wanna buy EEPROMS and microcontrollers.
I bought my parts quite a long time ago, but I can still see sometimes 8088 and other retro ICs available on eBay, but that may depend on where you are. Try AliExpress as well. Flash memories: again, eBay. I can see some on Farnell website as well. Futurlec has quite a good assortment (they also have 512k RAM). I hope that helps.
Honestly, Leonardo, I have a couple of 8085 in my drawer as well. This is a separate 8-bit architecture preceding the 8086 which has not too much to do with the x86 and having more to do like the similar Z80 family. I will, therefore, leave it to someone else to cover that, while me keeping on to the known x86 family which I'm familiar with for over 25 years. I'm sorry to disappoint you on the 8085, but I hope I can keep you enjoying watching me playing with an 8088 instead? Se you there!
@@SladorSoft Thanks to responst. The 8085 seems kind of hard for me, that is why i like Z80 (see in my channel). I hope you go far way with video controller, compact flash, and outher advanced devices. I have so much curitosity about 16 bits.
hey I am trying to do this on my own so a few questions. 1) What processor should I buy? I am finding 8088 ...8bit processors from intel. I assume they will come with data sheets but I want to follow this as is first so please advise. 2) what is the resistor and LED combination that is put in for data lines? Can you give their attributes how much resistance and what kind of leds to buy? 3) for clock you created a circuit yourself but didn't go in details so can you share what to buy for that please? Thanks
Hi there! Thanks for watching and here are the answers to your questions: 1) Yes, I'm using 80C88 - any manufacturer would do it. You can find the datasheets on the Internet easily. I show the relevant parts of it in my videos (including the pinout) as well. 2) Any LEDs would work. Since we are using the 5V logic here and an LED usually needs a few mA to light up, the resistors could have values from around 470 Ohms to 2.2k. It depends on the LEDs, so you can experiment. I found my blue ones really bright at a small current, so used the 2.2k with them. Others are 1.2k in my case I think. 3) I showed the schematics around 12:14 mark (the clock and reset circuit is in the left bottom part). Have a look at my GitHub pages where I publish all the schematics as well. I used two ICs: 74HC14 and 74HC74 (both can be HC or HCT). I missed putting the resistor and capacitor values on the schematics - they could be something around 10-47k and 1-10uF respectively. They are only used there to debounce the buttons, so the values may vary.
@@SladorSoft Thanks for your offer to help. I have ordered the parts online and waiting for them to arrive. Is there an email I can contact you on in case I get stuck? Thanks.
Wait so the same pins that output the memory address, somehow also take the input from memory?? How does that work? The direction of power flow must change internally right?
Yes - that's correct. These pins are bidirectional. First, the address is asserted on all 20 lines, the ALE signal gets active. One clock tick later, these "common" pins (AD0-AD7) may switch to be inputs when the CPU reads the memory, which signifies by issuing the RD signal. That's why you need latches to store the address for the whole bus transfer. I hope it gets more clear in the "part 2" video.
Just found your series after another UA-camr (@rehsd) gave you a shoutout in his breadboard 80268 series. I really like your clean presentation and style - subscribed! Thanks!
Oh! Cheers for that! I wasn't aware of him and thanks to your mention I started watching his videos. It's incredible that he has made such a big progress in just a few months! I wish I had more time to speed up my series, because I too have quite a few ideas for the series, including something even better the 286 ;-) Can you point me out exactly which episode he gave me the shoutout, please? Thank you!
Hello. I copied your project, but instead use a nec v20. What modifications shoud I do with the contraption that drive the CLOCK and RESET signals to meet the 50 duty cycle? Many thanks and more power!
Hi there. If you are asking about the manual clock I used in the part 1 then you don't need to worry about the duty cycle - it's way too slow to make any difference. If you think about a high frequency generator, you can use the oscillator built with 7414 from part 4, but at its exit add a flip-flop (7474) like the one in the manual clock here in part 1. The flip-flop will guarantee 50% duty cycle. I'd draw a schematic, but I cannot include any pictures here in the comment. I'll create a FAQ on my webpage next week and your question will be the first one there. Thanks for that!
@Geo4win well, it depends what do you understand by "swap". If you mean to remove 8088 and (somehow) connect 80386 to the existing components around, then: "no" - it is not possible due to many different reasons. But... if you ask if it is possible to build a similar contraption and observe what happens on the processor's busses, then: "yes" - it is possible and I'm planning to show you exactly that in one of the future videos ;-)
It looks like the 8086/8 is the latest x86 compatible with breadboards. The 80188/6 and 80286 have square PLCC-68 packages. The 80386 and 80486 have PGA packages, although still 0.1 inch.
I'm not in India, so I cannot tell you for sure, but does not AliExpress post worldwide? (Just to be precise: you need a 8088 - not 8086 if you want to follow my steps). Cheers!
Hi there! That the question which was already asked several times here. Since they are not produced for a long time, you can only hope to find them resold on websites like eBay, AliExpress or similar. It is much easier to buy 80C188 instead and that's why I focused on this CPU starting from episode 7 of this series.
Well, since it is not manufactured for a long time now, you can try some second hand sources. Try looking for "80C88" on eBay or AliExpress. At the moment of writing this comment, AliExpress lists one cheap source of "80C88-2" - the "-2" part means that it's the faster, 8MHz, version.
MS-DOS was written for 8088 CPU, so it is compatible, yes. Obviously, to run MS-DOS you need much more than just a CPU. For example, you need a storage to load MS-DOS from, you need a keyboard controller, a graphics card to display anything on, etc. If you look at my more recent videos, where I build a 80188 system, you will find that I'm working towards this goal - already added a disk controller and more is coming, so please stay tuned!
@@SladorSoft Luckily - it was not the CPU but the noise generator I called a clock. Created a better clock source and was able to "reset" and watch it load FFFF0 on the bus then count up until it was not able to go any further. next step - get the NOP instruction loaded. thanks for the encouragement.
Hi there! Try eBay or AliExpress. Search for "80C88". Also, you may try to search in Google and switch the results to "shopping" - that gives me many results.
Thank you and I totally agree with your thoughts, hence my series of videos. I hope you have at least some part of the fun of what I have while building my computer!
i can not tell a lightboard from a computer. did you made the ohm resistance calculation. so your board does not generate heat. before you assembled it. you know computers. but you are not an electronical specialist engineer. upfront you can calculate ohm versus current overall value of your cirquite board. and adjust components accordingly . also. does your design serve a usefull purpose or do you use the parts like Lego° ? it looks good ?
i think you made a "stove" classic hilarisch misstake. but you need to start somewhere. do you want to take an infrared tempreture picture of your design. or do you use this space age technology to bake eggs. ? the guideline is not to make the heat generation ,higher the room tempreture. the highr the kelvin, celcius fahreheit, the lesses the electrical conduction. causeing a cascade of more heatvgeneration. also. if you out those part so close togehter. you will get radio eletricalmagnetic interfenrentie between compounends. and signal distortion. i see you also dont use mass. all thou i dont know what that means. maybe ask a friend. wich has "all that" as a temporairly "look over your shoulder". those.. ingredients are quit expensive. please save them forever. also when a faster version of "black blocks with pins" will come out. good luck.
@adobejazz I know, right! And he perfectly changed his accent to a foreign one ;-) But, seriously, his videos - watched during the pandemic - inspired me to have a go with my own channel.
![First Real Programme - Building and programming a 16-bit Intel x86 breadboard computer [part 2]](http://i.ytimg.com/vi/FC1Pchr4ngg/mqdefault.jpg)
![First Real Programme - Building and programming a 16-bit Intel x86 breadboard computer [part 2]](/img/tr.png)
Ben Eater want to know your location !
Right behind you
😂😂
Hhhhhhh ben eater will get jaleous
True😂😂😂
I just get recommended this video after 4 months of the upload, I'm very upset because I've been looking for this content before, I'm very willing to watch all your videos because nobody has explained this CPU at electrical level, just software and debuggers and things like that. Thank you very much.
Thank you very much for your comment. Out of these 4 months, three were very very slow in terms of growth. Just a month ago I had around 20 (!) subscribers. The more nice comments (like yours) and likes I get, the more often the videos may be recommended to new viewers. So thank you all and stay tuned for the next video.
Awesome video man. Ever since I saw Ben’s video with the 6502 I thought how about doing this with a 8088, glad to see someone is already doing it!
Thank you Tom!
This is fantastic! Can’t wait for the third video!
Thank you very much. I'm really having lots of fun doing this. I'm really happy that somebody may like what I do. Unfortunately, I had to take a break from this during the summer holiday, but the next video should be available in the first half of September.
I wish I had known what I know now and could find these kind of videos when I was learning. Makes a lot of low level stuff very clear. Thank you very much!
Mikey, thanks for stopping by. I'm sure there is many more better videos out there, but if you can spend a moment around here, I'd be more than happy having you around. My only aim for the audience is to have at least a tiny fraction of the fun I have building these contraptions on the breadboard. That's all it is, thank you staying around here!
Technically the NOP opcode (0x90) is for the XCHG AX, AX operation, which would swap the AX with itself (or rather its contents). Whether or not a given x86 CPU actually performs this operation is implementation dependent.
It is nice to see the venerable 8088 used in a video like this. Thanks!
Yes, of course, you are right. The encoding of "XCHG with the accumulator" is 10010rrr, where the "rrr" is 000 for the AX. I didn't mention to avoid confusing those who didn't know the platform well. Thank you!
Excellent presentation. I have built my own 8088 system, which implements single step, but I never considered a solution whereby the clock of a CMOS processor could be stopped. You learn something new everyday!
Thank you very much. Yes, the clock of the CMOS version can be arbitrarily slow, but it is true only for the CMOS, which you can tell by the letter "C" between the "80" and "88". The datasheet of the HMOS version says that the maximum clock cycle period is 500ns which translates to 2MHz.
I know this isn't exactly related, but it kinda is. I got a couple interesting brief stories regarding the clock stopping...
First situation is rather simple. I used to repair and modify cheap digital watches in my teens, back in the 90s. I discovered quite by accident that if you touched the pins on the quarts crystal oscillator, the display would go blank and the time would get stuck, until you removed your finger anyways.
Second story is much more odd though. Once I had an HP laptop come into my computer shop, which was acting rather odd after they had dropped it. Everything appeared to still be working, more or less. But we found viruses on it and chalked the weirdness up to the viruses, so we decided we should reinstall Windows ya know..
This is where things got really weird. As we started reinstalling Windows, it would just randomly lock up, like solid. Well we had many computer repairs at the same time so it sat there like 4 hours stuck, in the middle of XP reinstall.
But as soon as I lifted the laptop up, my fingers pressed in a little in the middle to balance it ya know, but when I did the computer suddenly started running again haha! And you could repeat this too, set it back down on the flat desk and it freezes, lift it up by hand and it keeps running right where it left off flawlessly!
I dunno what exactly went wrong with that timer circuit, but it was pretty obvious that there was a bad solder connection some damn where.
Whatever connection/line broke loose was like a damn pause button for the CPU.
I built a breadboarded 8088 system for my Sr design project in college back in 1988. I still have the project breadboarded but wires came loose and corroded.
Looking to reverse engineer and rebuild it so this is good review.
I still have my 8088 system build on a (homemade) PCB 20 years ago. Because of many changes I applied to it later on, the PCB looks really messy and I'm not brave enough to power it on ;-) Thank you for your interest!
Make sure to put an "Intel inside" sticker on it!
intel outside
Thank you for the perfect information and great explane , my 8088-2 is working perfect now , i made a lot of tests with no result before , but now it works
I'm really glad I could help! Thank you.
В 1986 я собрал свой первый контроллер на К1810ВМ86 и DRAM К565РУ5 на 128kb. Использовал при этом проводной монтаж микросхем.
In 1986, I assembled my first controller using K1810VM86 and 128kb DRAM K565RU5. I used wired installation of microcircuits.
russian cpus are cool as hell, cpushack introduced me to them and theres just something cool about the white and gold ceramic packaging they use. id love to get my hands on an old russian 8086 machine
I am writing an emulator for the 8088 and there is something really satisfying to thee that my emulator is very accurate compared to real life, I knew it because I read the documentation about a thousand times a carefully implement it, but still, to see it is very satisfying.
Nice video and nice subject, I kind of wanted to build my own computer based on an 8086, maybe one of my future projects :)
look into 86box or PCEM
Can you show us please 🙏
Me:Start finishing Ben Eater's breadboard computer series.
YT: But wait.. THERE IS MORE !
Thanks for your comment. Of course I'm aware of Ben Eater's videos and I appreciate them a lot. I'm not here to compete with him at all. I just thought that I'd be able to share my experience in programming Intel CPU's while having fun rebuilding a working machine on a breadboard. I must say that Ben's videos kind of inspired me to do what I'm doing here, really. I hope you'll enjoy the rest of the series.
@@SladorSoft Well actually i meant that as complement like expansion/extension/addition to Bean Eater with provide us with more glorious low level nerdy shit i(and people like me) love and enjoy.
Check out James Sharman's 8bit Pipelined CPU. It's excellent; he's designed his own CPU, VGA, Sound, etc., from scratch in 100s of videos. On Breadboard and PCBs. All open source.
Aguardamos o décimo vídeo desta fantástica série de vídeos! E desde já agradeço sua disposição para dividir com todos nós os seus conhecimentos. Muito Obrigado!
Obrigado meu amigo! Next video is almost done - I am struggling with finding enough time to finish it. I have plans for at least 3 more videos in this series after which I'm going to design a new, hopefully final PCB for this computer.
Beautifully clear demonstration of the operation of this good ol' processor 👍
@ms767210 - thank you very much!
Watched this a while back and realized I never left a comment, and engagement is important :P Great series! I hope to see a lot more in the future!
It is important indeed. Thank you for your comments!
Legit content, on this channel, man, so well done !!!!
вау, я никогда не думал что такое может быть очень интерестным, я правда не разбираюсь в программировании(к тому же старом, я об asembler) я только могу собрать копьютер кому нибудь, а понять его полностью, и использовать для своих целей, эт мега круто и интерестно. Подключить провода и сделать из него что то своё - взрыв мозга. Автор, большое спасибо за твой труд! Хоть тебя и смотрит определённо малая аудитория, но это правда очень интерестно и ценно для меня и остальных, мне даже книгу никакую не пришлось читать))
p.s. ты хорошо обьясняешь
Videolarınız âdeta biler kütüphane değerinde, Şimdiye kadar daha sade bir anlatıma henüz karşılaşmamıştım, Bu sebeple bilgisayarıma arşiv olarak indirmiş bulundum,
Türküye den Selamlar
Thank you very much. I'm really happy that you found it useful!
Very nice explaination! I like these low level, low complexity approaches! Gives a lot of insight!
I'm really glad you enjoyed it! There is plenty more to show in the future videos. Thank you for your comment.
@@SladorSoft inspired by this video, i got a mindset it is feasable to build a minimal system..I made a PCB together with some logic and got my own system running now
Thanks for this video!! With this, I could fix some mistakes regarding my design with a NEC V20 CPU and now it works.
Glad it helped!
The bus logic of the 808x chips always weirded me out as a tinkerer. The 6502 made interfacing so simple on a breadboard.
Intel 808x CPU supports >1MB by design, 1MB is IBM PC limitation. In every memory cycle 808x outputs 4 status bits on the pins which can be used to separate/extend memory segments for code, data and so on.
Oh that's beautiful. I've looked into the 8088/8086 in the past for potentially using in a homebrew computer, but the multiplexed busses put me off. Also I thought I remember some clock phase requirements, but I might be wrong. Didn't know there's a static version either, nice.
I still prefer the motorola 68000, but it would be interesting to give the 8088 a try at some point; should be fun.
Subscribed to remember to watch the rest of your videos about it.
Hi, do you know about some M68k boards available or CAD drawings ? I would not want to Wire Wrap such a board.
This is excellent. Keep going! :)
I've recently gotten into assembly by writing a fibonacci sequence program that takes command line arguments on Linux. It was a neat project, and definitely taught me about how x86 assembly works, but I'm not sure what my next step should be. Perhaps my solution lies in creating something with an older piece of kit like this one.
I have my original 8088 (IBM PC) and also an NEC V20 that someone gave me which is compatible but a little faster on some opcodes. I just checked for 80C88 to follow along but they are out of stock. I'm also watching John's Basement where he explains the pins for the Z80 so it's cool to see what is the same and what's different.
Hi there. Yes, I'm aware of the fact that it's quite tricky to buy 80C88. In part 7 I introduced the 80C188 which is much easier to find on eBay or AliExpress.
@@SladorSoft oh cool, thanks!
cool I have been doing something like this with the 8086
Well done! You just did what I did at school in 1984 😁 OK, your manual Clock circuit is better/more precise! Needles to say, I instantly subscribed to your channel 👍
Amazing man I building something like this but it achieves 16bit by running two 8bit processors into each other. (I call it a 8x2 computer because it's not 16 bit technically)
This is just as good as Ben Eater's content, but for the x86!
I'm really happy that you like it. Thank you very much - that's really flattering.
Ben Eater ++ .... great project ! TY!! new sub indeed :)
a great explaination of the clock diagram ever seen. congraats! very well done. who can't thumbs up this video?? :)
Thank you very much! I wouldn't compare myself to Ben, but I'm really happy that you like it - this was my first video I've ever done.
It's an electrical question about the resistors. How does putting a resistor between, achieves its "state" (1 or 0, or Voltage or ground) to be recognized only as data (when the CPU reads from "memory"), and not as an address as well (when the CPU requests what address to read data from)?
PS: I have been a software developer for many years, but I don't know that much from the electrical side of things.
Hi! The AD0 - AD7 pins are bi-directional. It means that they are sometimes outputs, when the CPU asserts the address bits (when the ALE is active) or when it writes data to memory, or inputs, when the CPU reads data from the data bus. In the latter case, those pins have very high impedance and therefore can be driven by the resistors from either 0V or 5V. When they become outputs, the CPU is driving them instead, setting the required voltages. The resistance of the resistors is high enough (a few kOhm) for the CPU to override the voltage level of the pins. If the resistance was too small, we could damage the CPU as the current flowing from the CPU through them would be to big for the circuitry of the CPU to handle.
This above is also correct in all other similar cases as well, but the 8088 has in fact a special circuitry on those pins which determines the upper resistance value for those resistors. These pins need to be driven with at least 400uA to be correctly set to a logical level. That means that the resistors' values could not be greater than 5V / 400uA = 12.5kOhm.
I hope that makes sense (without drawing example schematics).
That's a fancy NOP slide.
I really liked your project! Thanks A suggestion to improve the visualization of CPU pins - Hex display HP 5082-7340
@JoseGustavoAbreuMurta - Wow! These are really cool! I've not seen them before. Had I seen them when I was starting this series, I'd definitely use them. These days though I'm not really relying on looking at the buses anymore while making my videos, but thanks again for your great idea.
this is pretty cool
where did you get the power supply
Hi,
Since I needed 5V supply, I simply used an old mobile charger. I cut off the micro USB plug and soldered the pin header instead.
Thanks Mike!
fantastic work, thank you for creating this.
in your videos, you refer to 74hct logic, but in your schematics, 74hc logic.
does it make any difference for the 80c88 or V20 chips?
Thanks Graeme!
Yes, that's a fair point. In this case there is no difference between HC and HCT, so I used the general HC family in the schematics, but I had some HCTs in my drawer, so I had used them in the videos.
The difference is important only when you mix these with the LS series chips which have different voltage levels for both 0 and 1. I tried to explain that in the other video: ua-cam.com/video/7_hZLauyYRg/v-deo.html
Is it possible to provide the schemas and values of the used capacitors, resistors, ...?
I am planning to put together a simple website where I would publish all schematics, source code and other details for reference. Currently I'm focused exclusively on publishing the next video (which should happen finally this weekend), but after that I'll think about this website. I'd like to ask for a little patience as this is my after-hours project and initially didn't expect to get this interest honestly. As to the values, I assume you ask for these in the clock circuit (around the button). I used some common sense arbitrary values: R around 10k and C around 10uF. The resistors on the data bus in the 1st video were around 2.2k.
my high school dream is using computer processor to make video game.. i did use 8088 processor to build LCD game.. i think video game thr graphics controller is most complicated then processor.. recently im thinking using 8751 as video game processor bcoz i like yhe ceramic with quartz window able to see the chip ..
That's interesting, but personally I'm a little bit too lazy to use anything involving EPROM these days (not that I didn't use it back in the past), especially when trying to fix a problem by re-flashing and testing several times in a loop.
But if you follow this series, I can promise that I will be going towards building a full-featured computer and write a video game for it.
@@SladorSoft That will be nice.i will check your video later again and follow up..
yes agree to re program EPROM is troublesome. but if can try in Flash memory like 28C64 or something then once the firmware work then will program in 2764 or something.. make the RAM large enough so all the software store in SD card using SPI.. i did successfully write in 8051 assembly code to access SD card under 2GB , FAT16 once the firmware work well everything will pass down to SD card like harddisk.. the only thing 8751 dont have Ready and hold pin for DMA..etc i still not sure is it possible to modify by stop clocking the process to let it access the data bus.
For video game project i still not fullty understand how the NES or SNES system work.. i think the most complicated will be the Graphics portion which can handler spirit and front moving object..
Nice! Keep uploading videos please
I have already recorded the next video - now I'm in process of editing and creating the "graphics" covering my commentary. Thank you for watching and your patience ;-)
Great video.
Hi, small question - what is RESET level during the operations? It was 4cycles HIGH, then 8 cycles LOW and what next? It is kept high or low?
The RESET is active HIGH. Also, it needs to be HIGH at least 4 cycles to reset the processor. As soon as it changes to LOW, it initialises itself for approximately 7 cycles after which the CPU starts fetching and executing the programme. For normal operation RESET needs to stay LOW at all times. The first 7 cycles is just the initialisation of its internal state before normal operation. Hope that clears this a little bit.
@@SladorSoft wow, thanks for incredibly detailed answer, it helped a lot!
no clue if this will be seen or not but does any place have a bill of materials of what chips and other items that are used in this project? I know there are schematics on the page, but looking for a shopping list I guess :)
Of course it will be seen ;-) I read all the comments on this channel. You are actually not the first person asking for the BOM, so, if people find it useful, I have decided to put it somewhere on my website: slador.uk/ sooner or later. It will probably not happen this week, as I would like to focus on my next video, but I'll try to make it soon.
Most excellent.
Cool project. Are you also planning to write your own ROM BIOS so it can eventually run MS-DOS?
Thanks!
No, not really. The main reasons are: lack of any kind of a storage device and graphics card - the 20x4 LCD is a little to small to make it a usable "screen".
I am considering building a kind of a graphics card device as a future plan at some point though. This series was rather meant to allow me having fun tinkering with the 8088 - not to build a proper computer ;-)
@@SladorSoft You could try emulating an MDA adapter, which would be less difficult since it's text only. Or get data in and out of the computer using a UART and a serial terminal.
oh that's beautiful art...tnx man
Thank you!
HaHa we have 8085, 8086, 8251 in this semester for uni. i have read them all but couldn't understand few things. Yourvideo help to catch those points.
Thank you so much! Being helpful in any way is more than I ever expected! Unfortunately, I have no experience with the others in opposite to x86, so probably won't cover them.
13:50.. Memory map is not correct... start and end address was switched and ordering .... CS start from 0000H and DS, SS and ES (FFFFH) side 😀
Hi @hyblidblackbox8847. I'm not entirely convinced that it is incorrect. It's intention is to show that each segment register can point anywhere in memory and that its segment is 64kB in size. There is no assumptions about where each segment actually is or what order they appear. The only constrain is that after reset, the CS is initialised to 0xFFFF.
You said that start and end are switched, but memory maps are usually created from bottom up and this diagram follows this convention.
I would defend this diagram even if I wasn't its author. It was taken straight from the CPU datasheet. Funny thing is that it does have a mistake after all, which nobody pointed out: the size of the CS segment is labelled as "64k-bit" when it should read "64k-BYTE" ;-)
@@SladorSoftMy apologies. I checked Intel's data sheet.. You are right. My apologies.
@hyblidblackbox8847 - no reason to apologise. Any input is welcome. Our comments here could also be useful for others interested in the x86 architecture. Thanks for that!
Thank you for this series of videos. I have a question. I follow the same steps you follow to get the FFFF0H but I get a FFFFFH. What could be happening?
Hi @cesarari007. It is really hard to answer your question, without looking into your contraption and taking some measurements. The reason could be anything like faulty CPU, mistake in wiring, reset signal not applied (or not removed when it should be), incorrect supply voltage and so on.
I would start from making sure that your clock and reset signals changes as you expect them to. Again, the "reset" must be held active for at least 4 clock cycles, then it needs to go to "0" and after 7 more clock cycles the FFFF0H should appear on the address lines. Putting LEDs in both the clock and reset lines should help visualise their levels.
I'm sorry that I cannot give you more specific advice.
How did you build your clock and reset circuit? Which chips are used for that? Thanks.
@mihirsevak4456: the schematic is shown in the video around 12:14 timestamp (the circuit you're asking for is in the bottom-left part). It is also available on my GitHub: github.com/sladorsoft/Intel8088OnBreadboard
I used 74HCT14 and 74HCT74. The couple of the pull-up resistors are around 10k and the caps are 1uF
Correction, the IBM PC was early 1980s, not 1990s.
Yes, someone else has already pointed this out. It was just my mispronunciation. Of course it was 1980s.
can you provide the list of all the parts and equipment needed?
@malikahmed49 - thanks for having a look.
My idea in this series was to show and talk about every chip I add to the contraption. Also, when I make changes I always show the schematics with all the elements used at the moment. I was hoping that it was enough to replicate the contraptions. Have a look at my GitHub where I added all the schematics for every video. They are in two formats: the native KiCad and the PDF, if you don't have (or want) the KiCad installed.
Very excited 😊
I'm excited as well, Alexander, believe me . The whole YT thing is all new to me as well and honestly, until the latest moment, I cannot tell if the script I planned would work as expected. I try to be honest when I record these and if something does not work as I planned, I am going to state that clearly. So far, so good!
@@SladorSoft you are doing an amazing job till now. It almost feels like a Ben eater video. Really high quality. 👍🏻👍🏻
I've always wanted to know is it possible to build a computer that can run windows 3.11 if so what parts would I need
That's a really interesting question. I assume that you are asking about building the computer from scratch (like I do in these videos).
First of all: it is not possible to run Windows 3.11 on either 8088(6) or 80188(6) as it uses the CPU's protected mode. It can run on at least 80286 in so-called "standard mode" or 80386 in the "enhanced mode". Despite Windows 3.11 being a 16-bit OS, the "enhanced mode" is particularly interesting, because - which is not immediately obvious - Windows itself is one of the virtual machines running by a 32-bit (!) hypervisor. Then, any MS-DOS processes started under Windows run each in a separate, additional VM running in the CPU's "virtual 8086 mode".
I think it's quite interesting, in technical terms, because most people would assume that Win 3.x were only a "shell" running on top of MS-DOS, while it was so much more under the hood.
After this long introduction, let me finally answer your question. You need at least 80286 CPU, at least 1MB of memory, VGA controller, keyboard and serial port (for serial mouse) controllers, some storage and a controller chip for that - shortly speaking - quite a lot. And I haven't yet mentioned lots of logic chips gluing everything together. And all of it would probably need to be IBM-PC compatible, so the controllers would need to have standard I/O ports and memory locations.
To simplify my 80188 computer I decided not to follow the IBM-PC compatibility (not to say that you would not be able to run Win 3.x on it anyway), but I hope it will be able to run some of these: FreeDOS, MS-DOS or elks at some point.
@@SladorSoft right now I have thoes chips I’m gonna get 1pcs 82C450 1MEGABIT Dram VGA Graphics Controller Sis FT232RL FTDI Module USB to Serial for Arduino Mini USB to 232 FT232 USB to TTLMiNi ENC28J60 Ethernet LAN Network Module For Arduino SPI AVR PIC LPC STM32Macronix MX29F1615PC-10 MX29F1615 16MBIT FLASH EEPROM PDIP40 X 2pcs PIC18F4620-I/P PIC Microchip microcontroller 40MHz Flash
50 MHZ Full Can Footprint Dip14 3V3-5V Crystal Oscillator maybe we can work together and our brains can make this seemingly impossible project real or as real as we can get with breadboards lol
@@SladorSoft also another thing I didn't mention I know it may be really complex in a lot of components and I expected that maybe we can help each other by creating a list of what exactly we need to do and possibly collaborate and make it possible or attempt to at least I mean it may take awhile for me to get the parts being jobless and all but still a good idea nonetheless
Thank you for your video! Can I use NEC V20 (wiki says that it CMOS too) to build similiar circuit with manually switching ticks of CPU?
Hi @yuriiradkovskyi8330. I have no experience with the V20, but I'm afraid that the manual clock may be impossible (despite that it's CMOS as you pointed out). According to its datasheet the maximum allowed clock cycle is 500ns, which translates to the minimum frequency of 2MHz.
@@SladorSoft Thanx, will buy 80C88 then for experiments like that
Hey there!
I'm thinking of starting this project. Where will I get the ic? May I know where you get your parts. I wanna buy EEPROMS and microcontrollers.
I bought my parts quite a long time ago, but I can still see sometimes 8088 and other retro ICs available on eBay, but that may depend on where you are. Try AliExpress as well. Flash memories: again, eBay. I can see some on Farnell website as well. Futurlec has quite a good assortment (they also have 512k RAM). I hope that helps.
Nice work. I have in drawer one 8085, is the same logic that 8086 ? And i made one computer with Z80, see on the channel
Honestly, Leonardo, I have a couple of 8085 in my drawer as well. This is a separate 8-bit architecture preceding the 8086 which has not too much to do with the x86 and having more to do like the similar Z80 family. I will, therefore, leave it to someone else to cover that, while me keeping on to the known x86 family which I'm familiar with for over 25 years. I'm sorry to disappoint you on the 8085, but I hope I can keep you enjoying watching me playing with an 8088 instead? Se you there!
@@SladorSoft Thanks to responst. The 8085 seems kind of hard for me, that is why i like Z80 (see in my channel). I hope you go far way with video controller, compact flash, and outher advanced devices. I have so much curitosity about 16 bits.
hey I am trying to do this on my own so a few questions. 1) What processor should I buy? I am finding 8088 ...8bit processors from intel. I assume they will come with data sheets but I want to follow this as is first so please advise. 2) what is the resistor and LED combination that is put in for data lines? Can you give their attributes how much resistance and what kind of leds to buy? 3) for clock you created a circuit yourself but didn't go in details so can you share what to buy for that please? Thanks
Hi there! Thanks for watching and here are the answers to your questions:
1) Yes, I'm using 80C88 - any manufacturer would do it. You can find the datasheets on the Internet easily. I show the relevant parts of it in my videos (including the pinout) as well.
2) Any LEDs would work. Since we are using the 5V logic here and an LED usually needs a few mA to light up, the resistors could have values from around 470 Ohms to 2.2k. It depends on the LEDs, so you can experiment. I found my blue ones really bright at a small current, so used the 2.2k with them. Others are 1.2k in my case I think.
3) I showed the schematics around 12:14 mark (the clock and reset circuit is in the left bottom part). Have a look at my GitHub pages where I publish all the schematics as well. I used two ICs: 74HC14 and 74HC74 (both can be HC or HCT). I missed putting the resistor and capacitor values on the schematics - they could be something around 10-47k and 1-10uF respectively. They are only used there to debounce the buttons, so the values may vary.
@@SladorSoft Thanks. I am trying to build this. Will let you know if have any issues.
Don't hesitate to ask, if you need help
@@SladorSoft Thanks for your offer to help. I have ordered the parts online and waiting for them to arrive. Is there an email I can contact you on in case I get stuck? Thanks.
Wait so the same pins that output the memory address, somehow also take the input from memory?? How does that work?
The direction of power flow must change internally right?
Yes - that's correct. These pins are bidirectional. First, the address is asserted on all 20 lines, the ALE signal gets active. One clock tick later, these "common" pins (AD0-AD7) may switch to be inputs when the CPU reads the memory, which signifies by issuing the RD signal. That's why you need latches to store the address for the whole bus transfer. I hope it gets more clear in the "part 2" video.
@@SladorSoft yes thank you, part 2 has cleared up the black magic 😅
very good thanks🙏
Just found your series after another UA-camr (@rehsd) gave you a shoutout in his breadboard 80268 series. I really like your clean presentation and style - subscribed! Thanks!
Oh! Cheers for that! I wasn't aware of him and thanks to your mention I started watching his videos. It's incredible that he has made such a big progress in just a few months! I wish I had more time to speed up my series, because I too have quite a few ideas for the series, including something even better the 286 ;-)
Can you point me out exactly which episode he gave me the shoutout, please?
Thank you!
@@SladorSoft if I find it again, I'll reply! I'll be rewatching! 😁
Hello, where can I find the documentation that you use? Is it from a book?
Hi there! Just try to Google for "intel 8086 datasheet pdf".
@@SladorSoft thanks
Hello. I copied your project, but instead use a nec v20. What modifications shoud I do with the contraption that drive the CLOCK and RESET signals to meet the 50 duty cycle? Many thanks and more power!
Hi there. If you are asking about the manual clock I used in the part 1 then you don't need to worry about the duty cycle - it's way too slow to make any difference. If you think about a high frequency generator, you can use the oscillator built with 7414 from part 4, but at its exit add a flip-flop (7474) like the one in the manual clock here in part 1. The flip-flop will guarantee 50% duty cycle. I'd draw a schematic, but I cannot include any pictures here in the comment.
I'll create a FAQ on my webpage next week and your question will be the first one there. Thanks for that!
@@SladorSoft thank you very much and more power to your channel!
@Slador is it possible to swap the 16bit CPU with a 32bit CPU?
@Geo4win well, it depends what do you understand by "swap". If you mean to remove 8088 and (somehow) connect 80386 to the existing components around, then: "no" - it is not possible due to many different reasons. But... if you ask if it is possible to build a similar contraption and observe what happens on the processor's busses, then: "yes" - it is possible and I'm planning to show you exactly that in one of the future videos ;-)
What is actually the latest x86 (mechanically) compatible with an 0.1 inch breadboard?
It looks like the 8086/8 is the latest x86 compatible with breadboards. The 80188/6 and 80286 have square PLCC-68 packages. The 80386 and 80486 have PGA packages, although still 0.1 inch.
can we still buy this processor anywhere? great video, btw!!!
Thanks! Yes, you can still buy them. Try eBay, AliExpress or Futurlec for example.
Inspired enough , and purchased 8088 cmos chip from eBay lol….
@bitlong4669 good job! Have fun with your 8088 :-)
IBM introduced their IBM PC or the “PC” was introduced in 1981.
Can anyone tell where can I buy this 8086 microprocessor from in India?
I'm not in India, so I cannot tell you for sure, but does not AliExpress post worldwide? (Just to be precise: you need a 8088 - not 8086 if you want to follow my steps). Cheers!
Can you please point where can i buy the processor?
Hi there!
That the question which was already asked several times here. Since they are not produced for a long time, you can only hope to find them resold on websites like eBay, AliExpress or similar.
It is much easier to buy 80C188 instead and that's why I focused on this CPU starting from episode 7 of this series.
@@SladorSoft Thanks a lot for taking time in answering that. Much Appreciated.
That is my pleasure to answer any questions here. It just may sometimes take a few days to reply like in your case ;-) Sorry for that!
Where can I purchase the chip from?
Well, since it is not manufactured for a long time now, you can try some second hand sources. Try looking for "80C88" on eBay or AliExpress. At the moment of writing this comment, AliExpress lists one cheap source of "80C88-2" - the "-2" part means that it's the faster, 8MHz, version.
Digikey still lists them, brand new, for around £5. Search "intel 8088".
Ugh, all those multiplexed pins.
Random jumper colors makes me cry lol.
I like you and Ben Eater
Thank you very much!
Subscribed!
Thank you Richard - that means really a lot to me!
Can this thing run ms dos?
MS-DOS was written for 8088 CPU, so it is compatible, yes. Obviously, to run MS-DOS you need much more than just a CPU. For example, you need a storage to load MS-DOS from, you need a keyboard controller, a graphics card to display anything on, etc.
If you look at my more recent videos, where I build a 80188 system, you will find that I'm working towards this goal - already added a disk controller and more is coming, so please stay tuned!
OMG 16 bit
just tried this (failed) - I think I have a bad chip - but rest assured I will try again.
Please don't give up! Swap the chip and try again - it's fun :-)
@@SladorSoft Luckily - it was not the CPU but the noise generator I called a clock. Created a better clock source and was able to "reset" and watch it load FFFF0 on the bus then count up until it was not able to go any further. next step - get the NOP instruction loaded. thanks for the encouragement.
@@RayMillTN1hi, can you share your schematics for the clock improvement? Thank you
69 missed calls from Ben eater
Where to buy this
Hi there!
Try eBay or AliExpress. Search for "80C88". Also, you may try to search in Google and switch the results to "shopping" - that gives me many results.
@@SladorSoft thank you for replying sir ... Is there any alternative
If you ask for an alternative to the CPU, there is a clone made by NEC called "V20" - you may also try to search for that.
The 8088 doesn't receive enough attention.
Thank you and I totally agree with your thoughts, hence my series of videos. I hope you have at least some part of the fun of what I have while building my computer!
i can not tell a lightboard from a computer. did you made the ohm resistance calculation. so your board does not generate heat. before you assembled it. you know computers. but you are not an electronical specialist engineer. upfront you can calculate ohm versus current overall value of your cirquite board. and adjust components accordingly . also. does your design serve a usefull purpose or do you use the parts like Lego° ? it looks good ?
i think you made a "stove" classic hilarisch misstake. but you need to start somewhere. do you want to take an infrared tempreture picture of your design. or do you use this space age technology to bake eggs. ? the guideline is not to make the heat generation ,higher the room tempreture. the highr the kelvin, celcius fahreheit, the lesses the electrical conduction. causeing a cascade of more heatvgeneration. also. if you out those part so close togehter. you will get radio eletricalmagnetic interfenrentie between compounends. and signal distortion. i see you also dont use mass. all thou i dont know what that means. maybe ask a friend. wich has "all that" as a temporairly "look over your shoulder". those.. ingredients are quit expensive. please save them forever. also when a faster version of "black blocks with pins" will come out. good luck.
Hmm! Cool eh!
This is Ben Eater… but why is he disguising himself as someone else? 😅
@adobejazz I know, right! And he perfectly changed his accent to a foreign one ;-)
But, seriously, his videos - watched during the pandemic - inspired me to have a go with my own channel.
Someone: Create's or presents somethign with computating power.
Me: "You know the rules and so do i" "say -good bye- ":
Will it run doom ?
..damN what is, this.: punctuation;
@@redi4ka951 -idk-
you are funny.
That was awesome 👌