Hi Config IOI, thanks for sharing your very clean and modular SAP design. And thanks a lot for mentioning my 'Minimal CPU System' at the end of your video as your upcoming project. Can't wait to see your "modularized" - and probably LED-ified(?) - version of it. Let me know how things are evolving :-)
Hi Slu4, thanks for taking the time to have a look at this modular design. I'm very excited about your amazing Minimal project. So far I have built two versions of it. One with your original PCB, second one is modular just like the one you see in this video. Everything works perfectly. Awesome design and code ! After building it modular, now I have a very good understanding of the hardware and logics in Minimal. However, I'm still struggling in understanding parts of the Microcode and also UART data exchange. I have read all your documentation but I'm still missing some points. I will post my questions on Minimal website. By the way, I have a new vertical modular design derived from Minimal. PCBs are ordered and I'm waiting for them to arrive next week. And yes, that one is modularized, LED-ified, and equipped with an optional Arduino Mega testing shield. I have been working on this for a while. The idea is to make it an educational/ learning piece. Will share the project once I have something to show. Again, thank you for the great design, videos, documentation. Will be in touch. Cheers !
@@ConfigIOI Sounds fantastic! Well, the microcode is some rabbit hole of it's own. Everything *just* works out on this minimal hardware. It was quite a ride... :-) See you on the Minimal Forum / Website. Cheers!
This is a good start to prepare for starting something like what James Sharman has created, with his pipelined cpu. I would recommend his channel next. Very worth watching!
Yes, I have been following Jame's design for a while. Very interesting project. Currently I'm working on Bravo project as you may have seen the videos on my channel. Bravo is also inspired by a design called Minimal CPU system by Carsten Herting. I consider Bravo as next step to Ben's 8 bit computer. Minimal/Bravo have a minimalistic approach to a relatively powerfull 8 bit computer. James build is more detailed with pipelined CPU and very cool interfacing.
Cool! I got my FPGA version running which implements either the Ben Eater 8 bit computer or the 6502 computer he is currently doing. Now I am now designing my own 16 CPU and compiler (which is written in Python).
That looks pretty neat. It’s taken me since the beginning of April to get to the control logic circuit. I can’t imagine how long it took you to design that. Great job
Very impressive! I followed Ben's project and did get the whole thing working (After about 6 months!). But I stored it away and now it does not work. So I'm very interested in your PCB version. I think it makes a great display project. Well done!!
Brilliant work, well done! So many different takes on Ben Eater's project and other basic computers in general... It's all a bit like a mini Renaissance, isn't it?
This looks like it would make a good kit - maybe you and Ben could team up. Ben's videos inspired me to build my own CISC 8 bit processor using Logisim Evolution. So far it is only a simulation but it could be built with standard parts.
I have a stack of PCBs that mirror breadboard layout and i thought about building Ben's kit onto those. This is a cleaner design for sure, when the boards are all set i'be interested in having a set made... Rather than use headers i'd probably solder wires and mount the thing in a frame to hang on my wall...
That will be a really cool projet. To be honest, been busy with life and Bravo project and didn't have much time to work on the Ben's modular build. Hopefully I get some time to go back to that project and refine the design.
Hi Pete, great. As I mentioned in the video, I need to go back and update the files with the modifications. So, once I have final/working files, I will post them. About Kits, not sure, Let's see how it goes. This is Ben's project, I really like to see people supporting him by buying his Kit.
Beautiful build. I spent several weeks working on board layouts and a card system for similar. I ended up adding some addressing bit/schemes and buried myself in production lol :) As a kit I betcha you could sell a bunch. Looks like a great open ended layout.
Random hardware errors. Add more capacitors to your boards. When you look at commercial boards from the 80's and 70's you will see a ratio of one capacitor per discrete component. It looks like you have one capacitor per board. Random hardware errors happen when two or more IC's switch (change state) at the same time. IC's switching puts stain on the power bus and the power source. Your power capacitors probably are under valued, adding more smaller capacitors at each IC will compensate for this. This type of problem appear totally random. Also each board should have an electrolytic capacitor on it's power input. Other wise the back plane should have a few electrolytic capacitors distributed at different locations. Adding a one to one capacitors ratio to your boards will solve your problem. Watch some videos showing vintage computer hardware. This is what your duplicating. You will see many more capacitors on the boards. Search for SWTP 6800 computer review videos. Good luck.
Thanks for the comment David. Great points. You are right, this actually has been the case with other projects like Bravo that I have done on this channel. This project need a revision to make it better.
Great suggestion. Another thing - a bunch of pointy pins behave a little bit like antennas and can catch some signals from the environment. I would suggest to avoid pointy bus contacts and also to use bus termination.
I'm trying to complicate my life by using a 4 bit data bus and a 8 bit address bus, which means that the 2 halves of the address need to be transmitted separately and reconstructed before accessing the memory. I gave up on using breadboards but it's way too early to do PCB, so I settled for wire wrapping which is incredibly fun, reliable and fast (once you get the hang of it).
Depending on how much you can spend on PCBs, you can create them when you "stabilise" a part of your design (such as a register or the clock) and then iterate if needed. I'm doing it for my experiments and it helps immensely. Now I have a fun mix of utility PCBs, protoboards and breadboards to "play" with... 😁
Cool Challenge. To be honest, I didn't know too much about wire wrapping before seeing your comment here. I watched some videos on it and it seems to be much more reliable than breadboarding. I normally do each module on breadboard and then convert it to PCB. But breadboarding is not easy specially with lower quality ones.
I have two suggestions that are minor nitpicks, which mostly come from my experience with older PCs and backplanes. 1- I would strongly suggest putting the power rails on the backplane rather than the clock board. That would make it easier to experiment with other clock options, as well as streamline the power pull of the system more evenly. 2- Swap the female and male headers on the bus board connections. Since the downward headers are reversed, it should use an opposing connector. The bus board being the same as the modules also means it's consistent which jumper connector type is used if a module is removed. Those are just minor nitpicks. Overall the idea is well thought out!
Thanks for the suggestions Brianna. Both very good points. In regard to putting power rail on a different module, that was actually in the initial plan but then the idea of keeping the project close to original design changed my mind. The idea is to have a layout very close to Ben's build so if someone wanted to build the PCB version following his videos, he/she can do that easily. Another reason is that Clock module is actually used in some other projects like 6502 (at least to test some parts of the build), so having it independent with it's own power rail makes sense. In regard to bus board headers, I came to the same conclusion after building the project :) . Now, I'm thinking about using stackable header pins which means we get female connectors on both Bus and the cards, and less soldering and less space on the cards ! LOL
Please share the files, we understand that they are not perfect, but my son and I excited about taking this project to the next level. We encountered tons of issues with floating pins when building on breadboards, so we know how to address them. So using your design as a starting point would be great. Thanks!
Hello any chance you can clarify how the BUS is created and maybe share schematic to the bus only? am having difficulty understanding bus architecture. thank in advance
The BUS is pretty simple. You have all the signals and the 5V on the bus. For each module that connects to the BUS, there is a header pin that connects the BUS to signals for that module. For example for clock, you have CLK signal, inverted CLK and the 5V power rail. For Program counter, it will be signals that relate to program counter, etc. But all of these signals are on the BUS board. They just terminate where they need to be connected to a specific module.
Thank you. I am assuming that the A and B registers are feeding the ALU via the bus as well? If I send you a schematic could you give your critique? Thanks again @@ConfigIOI
Bravo on a such a clean looking build. I did something on two pcbs a while back and failed miserably. I had all sorts of issues with signal reflection on my clock linex causing my sequencer to double clock. I know now how to fix it but am on to other projects.
Interesting, Was the issue related to the Halt line (going back to Clock) going high? I saw the same issue and used a pull down resistor on HLT line, I'm curious what was your issue/solution. I appreciate if you could share. Thanks
Thanks for your comment, I have been following James project for a while, it's a big project, I plan to implement part of it in a new build. by the way, I already built SLU4's project. It's amazing. Now working on my own design, will take a while but it's fun.
i also got all the way up to the control logic and just could not get the power or signals right and just stopped but could not disassemble it because how much work it was, i also have been thinking about using a pcb and solder because that may solve my issue
You are right, PCB could resolve some of the connection issues. However, there are couple of points that are important when you do PCB. You need to make sure that unused logic gates are pulled down/up. Also, If I rebuild it again, I will add capacitor to every chip. There are also some issue that may come up during the build, there are lot's of comments and videos about those on TH-cam and Reddit. So some minor changes are required to have it working perfectly. Hope this helps.
I spent most of today designing my own PCB for the clock module. I have a lot of things to think about next: do I want to try a surface mount version? I made mine all through-hole based on the breadboard components. Do I want to use the original chips (NOT, AND, OR; with lots of unused gates) or make it use 2 quad nand chips instead? Do I want to make it 4 layer? The one I did is 2 layer pretty easily with a ground fill on one side and +5V fill on the other. Currently I kept an LED on each 555, but I could just remove them like you and Ben did. Do I want to replace 2 of the 555s with a 556? A funny thing was while reviewing my breadboard clock module with the videos I found a few mistakes on my breadboard that somehow weren’t causing any problems. I am also debating: do I want to disassemble my breadboards as I go and reuse the chips on the PCB or buy new parts? I’m also think of making upgrades like having more RAM and a bigger address register. And finally the most important part: rounded corners and what color do I want to use? Red looks cool. :)
This is something that you will build yourself. Module by module, you can start by exploring Ben Eater's 8bit computer on breadboard. You can get the whole kit on his website. eater.net/8bit/
Yes, you are right, and there are some projects done with Z80 and 6502 at a fraction of size. But this was not the point here. The point is to build everything from scratch out of TTL chips. Please have a look at the orignal project videos by Ben Eater. This project is more an educational piece to learn logic circuits and computer hardware fundamentals.
What’s the minimal modules needed, or in which steps can you run the modules. Ben added the modules but did make some modifications. So can you also configure it for the in-between steps? What’s the clock range it runs stable with? Did you consider keyboard and vga?
The project has total of 15 modules (including BUS board). You will build first couple of modules and test them, then at the point where Ben connects the modules, you could do the same and connect them to the BUS board. You can NOT configure it for in-between steps. Meaning that you can not follow the change steps. You will just have the final version of the build for each specific module, though you can add the ICs gradually. You don't have to insert all the chips for specific modules like ALU. So, this build on PCB is probably for someone who either have built the project on breadboard or have some understanding of the circuits. That's why in my video I still recommend building all or parts of the project on breadboard to learn the concepts and then if you decided that you want to keep the project, transfer it to PCB.
Also, I subscribed, because I would like to see what you can do with making a modular terminal.... it would be great for this 8 bit version, but also applicable in other projects, if modular. otherwise having a way to swap to load mode - where an external device could modify ram... much needed once you get above 16 bytes of ram, unless you limit memory expansion to ROM only.
I had that issue trying to do a SMT version of that build. You might have more luck if you are you have easier access to a specific family (such as 74HCT, 74LS, or 4xxx CMOS) and invest a lot of time reading data sheets. It might need some time to get used to it, but digital is quite easy because ICs usually do the heavy-lifting for you.
I agree with emcosta. Just make sure you use the same family in each project. If you use 74HC, all chips should be from the same family. Do not mix HC with LS.
I had the same memory write problem when switching between run and program mode. It is due to the way the 74LS157 work. I explain the issue in detail here: th-cam.com/video/W2w9KVmyxRs/w-d-xo.html
Hi Michael, thank you so much for your reply and great video on this issue. I watched your video and it make sense. I'm going to try it on my build and see if it resolves the issue. Will let you know. I'm working on a new build now but you made me excited to go back to the project and see if I can resolve this old issue. Thanks again !
I like the guy, but ig its called sap1 and not ben eaters computer.... Its also not his own creation, and is from a book.... you can try creating the more advanced version of this computer named as SAP2 and subsequent
Ben Eater gives full credit in his videos to Malvino and shows the book, but Ben enhances the SAP-1. I have the book and the SAP-1 only has LDA, ADD, SUB, OUT, and HLT. No JMP or conditional jump! No flags. No STA or LDI either. The output is 8 bit binary, not base-10. The SAP-2 is a huge upgrade. It describes 42 opcodes. I’m not sure it’s meant to be buildable based on the info in the book but I could be wrong. The computer in this video is laid out exactly as described by Ben Eater but in PCB form. I think he deserves credit.
Hi Config IOI, thanks for sharing your very clean and modular SAP design. And thanks a lot for mentioning my 'Minimal CPU System' at the end of your video as your upcoming project. Can't wait to see your "modularized" - and probably LED-ified(?) - version of it. Let me know how things are evolving :-)
Hi Slu4, thanks for taking the time to have a look at this modular design. I'm very excited about your amazing Minimal project. So far I have built two versions of it. One with your original PCB, second one is modular just like the one you see in this video. Everything works perfectly. Awesome design and code ! After building it modular, now I have a very good understanding of the hardware and logics in Minimal. However, I'm still struggling in understanding parts of the Microcode and also UART data exchange. I have read all your documentation but I'm still missing some points. I will post my questions on Minimal website. By the way, I have a new vertical modular design derived from Minimal. PCBs are ordered and I'm waiting for them to arrive next week. And yes, that one is modularized, LED-ified, and equipped with an optional Arduino Mega testing shield. I have been working on this for a while. The idea is to make it an educational/ learning piece. Will share the project once I have something to show. Again, thank you for the great design, videos, documentation. Will be in touch. Cheers !
@@ConfigIOI Sounds fantastic! Well, the microcode is some rabbit hole of it's own.
Everything *just* works out on this minimal hardware. It was quite a ride... :-) See you on the Minimal Forum / Website. Cheers!
This is a good start to prepare for starting something like what James Sharman has created, with his pipelined cpu. I would recommend his channel next. Very worth watching!
Yes, I have been following Jame's design for a while. Very interesting project. Currently I'm working on Bravo project as you may have seen the videos on my channel. Bravo is also inspired by a design called Minimal CPU system by Carsten Herting. I consider Bravo as next step to Ben's 8 bit computer. Minimal/Bravo have a minimalistic approach to a relatively powerfull 8 bit computer. James build is more detailed with pipelined CPU and very cool interfacing.
Cool! I got my FPGA version running which implements either the Ben Eater 8 bit computer or the 6502 computer he is currently doing. Now I am now designing my own 16 CPU and compiler (which is written in Python).
I am interested in doing something similar with my terasia de10 nano. do u have more info to share?
@@wlan04wlan04 There are a fair few videos on youtube relating to making the sap-1 in an FPGA :)
Very cool to see the computer like this. You are inspiring sir.
Thanks you. Glad you enjoyed the project.
Awesome work! I had the same idea, but my project fizzled. It's great to see this up and running. Kudos!!!!
Thank you !
Nice! I bought the RC2014 pro kit because of my Z80 upbringing, but I love the spirit of your modular boards
Thank you ! Didn't have a chance to explore Z80 yet but that looks pretty cool !
That looks pretty neat. It’s taken me since the beginning of April to get to the control logic circuit. I can’t imagine how long it took you to design that. Great job
Very impressive! I followed Ben's project and did get the whole thing working (After about 6 months!). But I stored it away and now it does not work. So I'm very interested in your PCB version. I think it makes a great display project. Well done!!
Thank you. I'm trying to update the schematic files and then release them for everyone who wants to get the PCBs.
Agreed - this would make a great display!
Have plans in the work for a PCB version as well, with mods.
Awesome, would be cool if you post some videos of your project.
@@ConfigIOI Will see how it goes.
Love the project. I had the same idea but not the follow through. Super nice.
Brilliant work, well done!
So many different takes on Ben Eater's project and other basic computers in general... It's all a bit like a mini Renaissance, isn't it?
Well said!
Very cool! Be sure to update when you have the design files updated. 🙂
This looks like it would make a good kit - maybe you and Ben could team up. Ben's videos inspired me to build my own CISC 8 bit processor using Logisim Evolution. So far it is only a simulation but it could be built with standard parts.
Thinking about the brain power that went into this marvel gets my head to begin a quick shut down. Bravo!
I have a stack of PCBs that mirror breadboard layout and i thought about building Ben's kit onto those.
This is a cleaner design for sure, when the boards are all set i'be interested in having a set made...
Rather than use headers i'd probably solder wires and mount the thing in a frame to hang on my wall...
That will be a really cool projet. To be honest, been busy with life and Bravo project and didn't have much time to work on the Ben's modular build. Hopefully I get some time to go back to that project and refine the design.
Brilliant project. Love this! Looking at one of a number of Z80 based 8bit 'modern' computer board kits.
Nice setup in PCB, the SAP is incredible computer
This is fantastic - Looking forward to the EDA files - so we can do copies - or count me in for kits???
Hi Pete, great. As I mentioned in the video, I need to go back and update the files with the modifications. So, once I have final/working files, I will post them. About Kits, not sure, Let's see how it goes. This is Ben's project, I really like to see people supporting him by buying his Kit.
@@ConfigIOI Appreciate the response - I have bought his kit already - but I like the permenance of the PCBs
Beautiful build. I spent several weeks working on board layouts and a card system for similar. I ended up adding some addressing bit/schemes and buried myself in production lol :) As a kit I betcha you could sell a bunch. Looks like a great open ended layout.
Cool, thanks!
Very nice and clean.
Thank you!
Random hardware errors. Add more capacitors to your boards. When you look at commercial boards from the 80's and 70's you will see a ratio of one capacitor per discrete component. It looks like you have one capacitor per board. Random hardware errors happen when two or more IC's switch (change state) at the same time. IC's switching puts stain on the power bus and the power source. Your power capacitors probably are under valued, adding more smaller capacitors at each IC will compensate for this. This type of problem appear totally random. Also each board should have an electrolytic capacitor on it's power input. Other wise the back plane should have a few electrolytic capacitors distributed at different locations. Adding a one to one capacitors ratio to your boards will solve your problem. Watch some videos showing vintage computer hardware. This is what your duplicating. You will see many more capacitors on the boards. Search for SWTP 6800 computer review videos. Good luck.
Thanks for the comment David. Great points. You are right, this actually has been the case with other projects like Bravo that I have done on this channel. This project need a revision to make it better.
Great suggestion. Another thing - a bunch of pointy pins behave a little bit like antennas and can catch some signals from the environment.
I would suggest to avoid pointy bus contacts and also to use bus termination.
very cool! I had a similar thought when we started selling the kits
Great project, let us know when kit is ready or files
Thanks, will send the update in the comments.
I'm trying to complicate my life by using a 4 bit data bus and a 8 bit address bus, which means that the 2 halves of the address need to be transmitted separately and reconstructed before accessing the memory. I gave up on using breadboards but it's way too early to do PCB, so I settled for wire wrapping which is incredibly fun, reliable and fast (once you get the hang of it).
Depending on how much you can spend on PCBs, you can create them when you "stabilise" a part of your design (such as a register or the clock) and then iterate if needed. I'm doing it for my experiments and it helps immensely. Now I have a fun mix of utility PCBs, protoboards and breadboards to "play" with... 😁
Cool Challenge. To be honest, I didn't know too much about wire wrapping before seeing your comment here. I watched some videos on it and it seems to be much more reliable than breadboarding. I normally do each module on breadboard and then convert it to PCB. But breadboarding is not easy specially with lower quality ones.
I have two suggestions that are minor nitpicks, which mostly come from my experience with older PCs and backplanes.
1- I would strongly suggest putting the power rails on the backplane rather than the clock board. That would make it easier to experiment with other clock options, as well as streamline the power pull of the system more evenly.
2- Swap the female and male headers on the bus board connections. Since the downward headers are reversed, it should use an opposing connector. The bus board being the same as the modules also means it's consistent which jumper connector type is used if a module is removed.
Those are just minor nitpicks. Overall the idea is well thought out!
Thanks for the suggestions Brianna. Both very good points. In regard to putting power rail on a different module, that was actually in the initial plan but then the idea of keeping the project close to original design changed my mind. The idea is to have a layout very close to Ben's build so if someone wanted to build the PCB version following his videos, he/she can do that easily. Another reason is that Clock module is actually used in some other projects like 6502 (at least to test some parts of the build), so having it independent with it's own power rail makes sense. In regard to bus board headers, I came to the same conclusion after building the project :) . Now, I'm thinking about using stackable header pins which means we get female connectors on both Bus and the cards, and less soldering and less space on the cards ! LOL
Please share the files, we understand that they are not perfect, but my son and I excited about taking this project to the next level. We encountered tons of issues with floating pins when building on breadboards, so we know how to address them. So using your design as a starting point would be great. Thanks!
Hello any chance you can clarify how the BUS is created and maybe share schematic to the bus only? am having difficulty understanding bus architecture. thank in advance
The BUS is pretty simple. You have all the signals and the 5V on the bus. For each module that connects to the BUS, there is a header pin that connects the BUS to signals for that module. For example for clock, you have CLK signal, inverted CLK and the 5V power rail. For Program counter, it will be signals that relate to program counter, etc. But all of these signals are on the BUS board. They just terminate where they need to be connected to a specific module.
Thank you. I am assuming that the A and B registers are feeding the ALU via the bus as well? If I send you a schematic could you give your critique? Thanks again @@ConfigIOI
Bravo on a such a clean looking build. I did something on two pcbs a while back and failed miserably. I had all sorts of issues with signal reflection on my clock linex causing my sequencer to double clock. I know now how to fix it but am on to other projects.
Interesting, Was the issue related to the Halt line (going back to Clock) going high? I saw the same issue and used a pull down resistor on HLT line, I'm curious what was your issue/solution. I appreciate if you could share. Thanks
I was getting clock bounce. This will happen on long clock lines. Supposedly adding a 50 ohm resistor inline should fix it.
Nice one! Please keep us posted!
Should make a mini KIM1 or similar
Walkthrough starts at 12:42.
Nice job mate will keep you listed
Good to see in pcb ❤
Was just thinking about building something like this... but you beat me to it...
Great work.....cheers.
Beautiful job! Really nicely done!
How can I build the PCBs ? have you shared the Gerbers?
Your Ben Eater 8 bit PCB modular concept is amazing. Have you released the updated Gerber files yet?
Not yet, need to troubleshoot one remaining issue.
@@ConfigIOI Hope the issue have been sorted out. when will you release the Gerber files?
Incredible work man
Thank you! Cheers!
love it, you stuck to Bens layout. easyli understood
Glad you liked it!
Great Project. Your boards looks very nice. If you plan to expand it based on SLU4 videos, may i suggest the James Bates project too.
Thanks for your comment, I have been following James project for a while, it's a big project, I plan to implement part of it in a new build. by the way, I already built SLU4's project. It's amazing. Now working on my own design, will take a while but it's fun.
i also got all the way up to the control logic and just could not get the power or signals right and just stopped but could not disassemble it because how much work it was, i also have been thinking about using a pcb and solder because that may solve my issue
You are right, PCB could resolve some of the connection issues. However, there are couple of points that are important when you do PCB. You need to make sure that unused logic gates are pulled down/up. Also, If I rebuild it again, I will add capacitor to every chip. There are also some issue that may come up during the build, there are lot's of comments and videos about those on TH-cam and Reddit. So some minor changes are required to have it working perfectly. Hope this helps.
I spent most of today designing my own PCB for the clock module. I have a lot of things to think about next: do I want to try a surface mount version? I made mine all through-hole based on the breadboard components. Do I want to use the original chips (NOT, AND, OR; with lots of unused gates) or make it use 2 quad nand chips instead? Do I want to make it 4 layer? The one I did is 2 layer pretty easily with a ground fill on one side and +5V fill on the other. Currently I kept an LED on each 555, but I could just remove them like you and Ben did. Do I want to replace 2 of the 555s with a 556? A funny thing was while reviewing my breadboard clock module with the videos I found a few mistakes on my breadboard that somehow weren’t causing any problems. I am also debating: do I want to disassemble my breadboards as I go and reuse the chips on the PCB or buy new parts? I’m also think of making upgrades like having more RAM and a bigger address register. And finally the most important part: rounded corners and what color do I want to use? Red looks cool. :)
BTW, I just saw your Bravo project including the kits. I am intrigued!
Thank you. Yes, Bravo is a fun project.
great job. I presume you'll release the gerber files at some point? :)
Yes, that's the plan. Need some work.
You could’ve added, sockets or terminals for the LEDs to plug into a single PCB indicator panel.
Yes, the idea here was to be as close as possible to the breadboard version.
Guys i really want to know that where to get those cpu, ram etc. If anybody knows pls tell me.
This is something that you will build yourself. Module by module, you can start by exploring Ben Eater's 8bit computer on breadboard. You can get the whole kit on his website. eater.net/8bit/
Realy nice work, had the same Id, but never got to it :)
It is impressive don't get me wrong. But surely there's a beefier chip so the circuit doesn't end up the size of a table. The z80 maybe?
Yes, you are right, and there are some projects done with Z80 and 6502 at a fraction of size. But this was not the point here. The point is to build everything from scratch out of TTL chips. Please have a look at the orignal project videos by Ben Eater. This project is more an educational piece to learn logic circuits and computer hardware fundamentals.
Nice work! Thanks for sharing! 1 reset?
Thanks. not sure what you mean by 1 reset but if you mean a single reset signal, yes it's a single reset line.
Excellent..
Thank you! Cheers!
very nice
Thanks
Very nice project, do you make it open source?
If you mean releasing the PCB files, this is my plan. The rest of the material including schematics and codes are available from Ben Eaters website.
Nice work.
🆒 cool pcb
What’s the minimal modules needed, or in which steps can you run the modules. Ben added the modules but did make some modifications. So can you also configure it for the in-between steps? What’s the clock range it runs stable with? Did you consider keyboard and vga?
The project has total of 15 modules (including BUS board). You will build first couple of modules and test them, then at the point where Ben connects the modules, you could do the same and connect them to the BUS board. You can NOT configure it for in-between steps. Meaning that you can not follow the change steps. You will just have the final version of the build for each specific module, though you can add the ICs gradually. You don't have to insert all the chips for specific modules like ALU. So, this build on PCB is probably for someone who either have built the project on breadboard or have some understanding of the circuits. That's why in my video I still recommend building all or parts of the project on breadboard to learn the concepts and then if you decided that you want to keep the project, transfer it to PCB.
Also, I subscribed, because I would like to see what you can do with making a modular terminal.... it would be great for this 8 bit version, but also applicable in other projects, if modular. otherwise having a way to swap to load mode - where an external device could modify ram... much needed once you get above 16 bytes of ram, unless you limit memory expansion to ROM only.
Did you not like 64 bit rasp pi for $15?
am kind of a confused person to switch from analog to digital since most of the chips you are using are not in my country.
I had that issue trying to do a SMT version of that build. You might have more luck if you are you have easier access to a specific family (such as 74HCT, 74LS, or 4xxx CMOS) and invest a lot of time reading data sheets. It might need some time to get used to it, but digital is quite easy because ICs usually do the heavy-lifting for you.
I agree with emcosta. Just make sure you use the same family in each project. If you use 74HC, all chips should be from the same family. Do not mix HC with LS.
Pretty...
I had the same memory write problem when switching between run and program mode. It is due to the way the 74LS157 work. I explain the issue in detail here: th-cam.com/video/W2w9KVmyxRs/w-d-xo.html
Hi Michael, thank you so much for your reply and great video on this issue. I watched your video and it make sense. I'm going to try it on my build and see if it resolves the issue. Will let you know. I'm working on a new build now but you made me excited to go back to the project and see if I can resolve this old issue. Thanks again !
shouldn't we be redhcung to a 1 bit computer and reducing from rhere?
no
I like the guy, but ig its called sap1 and not ben eaters computer.... Its also not his own creation, and is from a book.... you can try creating the more advanced version of this computer named as SAP2 and subsequent
Ben Eater gives full credit in his videos to Malvino and shows the book, but Ben enhances the SAP-1. I have the book and the SAP-1 only has LDA, ADD, SUB, OUT, and HLT. No JMP or conditional jump! No flags. No STA or LDI either. The output is 8 bit binary, not base-10.
The SAP-2 is a huge upgrade. It describes 42 opcodes. I’m not sure it’s meant to be buildable based on the info in the book but I could be wrong.
The computer in this video is laid out exactly as described by Ben Eater but in PCB form. I think he deserves credit.
@@drivers99 ok. Thanks for sharing 👍
Excellent