If you want to build your own 6502 this is a great kit with amazing tutorials. He sells all the parts, but you can also source your own from Adafruit or whatever easily https://eater.net/6502
One of the big things about Ben Eater's kits is that all the parts he uses in his videos are still in production.
Other CPUs from that era are super interesting (Motorola 6800, 6809, the 68000, etc., Intel 8086, etc.), but they are no longer produced, so building systems requires sourcing new-old-stock or e-waste pulls from places like eBay, AliExpress, utsource, and so on. Eventually there will be no more of them.
I believe the only CPUs from that era still being manufactured are modern CMOS variants of the Z80, 6502, and 65816. Their clock rates are 10-20x what they were in the late 70's / early 80's.
68K’s are still produced by Rochester Electronics; they are still used in some embedded systems (allegedly automotive systems?), which is good news for kit builders!
Ben Eater kickstarted this whole hobby into my brain! I’m (hopefully) starting a 68010 breadboard computer this summer; already have the parts, just need to find the time.
Another fun (soldering) kit-maker is Lee Hart at sunrise-ev.com. His kits are always surprising in their cleverness yet understandability. Almost all of them have a 9600 baud serial port, yet no ACIA/UART in sight!
If the vendor is kswichit then I believe it is produced by Wichit Sirichote himself. I purchased a 6502 constructed board on eBay a couple of years ago, then followed up by purchasing four more directly from Sirichote himself. I used the boards to teach a series of short, introductory courses in CPU architecture and programming and the boards have worked flawlessly. I was prompted to post the link today when I realized what a saint the guy is and how he needs more recognition.
Hm, since that link didn't work for me either, I switched my DNS from Cloudflare's 1.1.1.1 to Google's 8.8.8.8 and that allowed me to view the page. Some weirdness going on there.
I built the 8086 kit from him mid-2020, and it was a simple enough kit to put together.
I had intended to use it to learn x86 assembly, and I did, but due to who I am as a person I got distracted by another project and moved on. I did learn some assembly and I think a skilled person could make any of these boards do useful work, though probably not very power-efficient work.
I purchased five of his 6502 boards, assembled, to teach some programming classes and they have been wonderful. I only just stumbled on this full list of his work today and was blown away by how much he has done and I'm incredibly grateful that he has shared it with the world. If you get a chance to purchase something from him or use his designs I promise you won't be disappointed.
But at the same time, they're (mostly) representative of the bulk of the 8-bit scene. They only go so far.
Ben Eater demonstrates what it takes to get a 6502 up on a breadboard (and, with the modern processors and RAM, it's not a whole lot).
In the Z80 world, there's dozens of little Z80 systems with a UART and a flash drive booting CP/M in all sorts of form factors.
But that's where it stops.
There isn't anyone going full boat with a comparable 8-bit video system. The primary question of folks looking at these things, or wanting to do one themselves, is "how do I do video". They all want memory mapped video. Many want color and sprites.
But even skipping color, something akin to a TRS-80 and it's 64x16 screen on a hacked TV set. Or the PET or Apple 40x24 B&W characters. Forget graphics and color and lines. How about "hello world"? I mean, Woz did it with paperclips and shiny gum wrappers, at least so I'm told.
That's where things go off the deep end. It's like there's these simple baby steps to get to a UART, but video? That's...just not in the cards.
Ben Eater did a nice series on getting a VGA video signal using discrete components. It's really informative.
Demonstrably video is very difficult. Apparently anyone that can decipher a tool like KiCad can come up with a 8-Bit processor and a UART. But nobody, anywhere, is doing video.
The few that are doing anything are these retro clones striving to duplicate C-64s, trying to step above the hobby market and break out with a commercial product. But even they struggle.
I just find it curious how this last step seems so out of reach.
The problem may simply be there's nothing to display video on. An 8-bit machine driving even a VGA monitor is asking an awful lot, and I don't know what it takes to convert composite video to run on a modern display, either a VGA or HDMI. I would think if someone came up with THAT circuit, composite in, VGA out, as a "black box", something the board designers could plug in to, like the old RCA boxes we used to use tuned to Channel 3, then maybe that's the breakthrough thats missing from the community. They they could fall back on the old composite circuits from that past.
Surprised to see this as a barrier, it's not hard to generate composite video in hardware/software and there's plenty of composite to VGA/HDMI converters out there (e.g. search Amazon for "composite to HDMI"). I've written plenty of code for PIC micros that generates full-colour PAL/NTSC signals (text and graphics); have to think a bit about how to make it memory-mapped from an 8-bit MCU, some sort of cycle-stealing approach seems feasible (brute-force approach would be to use dual-port RAM or an FPGA, but that doesn't seem in the spirit of 8-bit retro hacking).
Yea, I don't know what the barrier is. But there is some barrier. I would think that by now, and this hobby of make 8-bit CPUs is by no means "new", there would be some "oh, Frank did that and has a circuit" so that, at least, everyone makes a stab at using Franks video subsystem.
Could be just that this kind of thing lives on the boundary of electronics, software and precision timing (e.g. for PAL it's necessary to either clock a deterministic MCU at a precise multiple of the colour subcarrier, or use a pile of dedicated logic - lots of chips for TTL or cheat by using an FPGA). To me it just feels 'wrong' to use modern tech to implement a memory-mapped display on a Z80 (I still have a working Nascom 1 [0], which managed to fit a memory-mapped text display into a system with a total 2K of RAM).
https://gigatron.io/ "... low resolution video had come within reach of our design, without adding chips. This was possible by taking the unconventional step of bit-banging video signals from software, instead of designing a standard video generation circuit. ..."
https://basicengine.org/ "The VS23S010D-L ... is a static RAM chip ... (that) comes with a video controller. ... It comes with 128 kB, some or all of which can be used as a frame buffer ... has a "block move" feature, more commonly known as a blitter. It allows you to copy sections of video memory ... provides a dramatic performance boost in ... text screen scrolling and rendering of tiled backgrounds."
http://uzebox.org/wiki/index.php?title=Main_Page - Uzebox - "retro-minimalist homebrew game console. ... video sync generation, tile rendering and music mixing is done realtime by a background task ... easy and fun to assemble and program ... contains only two chips: an ATmega644 and an AD725 RGB-to-NTSC converter."
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[ 2.4 ms ] story [ 32.9 ms ] threadOther CPUs from that era are super interesting (Motorola 6800, 6809, the 68000, etc., Intel 8086, etc.), but they are no longer produced, so building systems requires sourcing new-old-stock or e-waste pulls from places like eBay, AliExpress, utsource, and so on. Eventually there will be no more of them.
I believe the only CPUs from that era still being manufactured are modern CMOS variants of the Z80, 6502, and 65816. Their clock rates are 10-20x what they were in the late 70's / early 80's.
Are you referring to this: https://www.rocelec.com/news/motorola-6800 ?
Unfortunately looking up the part numbers for the reproduced ones on digikey has them marked as obsolete.
Another fun (soldering) kit-maker is Lee Hart at sunrise-ev.com. His kits are always surprising in their cleverness yet understandability. Almost all of them have a 9600 baud serial port, yet no ACIA/UART in sight!
I had intended to use it to learn x86 assembly, and I did, but due to who I am as a person I got distracted by another project and moved on. I did learn some assembly and I think a skilled person could make any of these boards do useful work, though probably not very power-efficient work.
But at the same time, they're (mostly) representative of the bulk of the 8-bit scene. They only go so far.
Ben Eater demonstrates what it takes to get a 6502 up on a breadboard (and, with the modern processors and RAM, it's not a whole lot).
In the Z80 world, there's dozens of little Z80 systems with a UART and a flash drive booting CP/M in all sorts of form factors.
But that's where it stops.
There isn't anyone going full boat with a comparable 8-bit video system. The primary question of folks looking at these things, or wanting to do one themselves, is "how do I do video". They all want memory mapped video. Many want color and sprites.
But even skipping color, something akin to a TRS-80 and it's 64x16 screen on a hacked TV set. Or the PET or Apple 40x24 B&W characters. Forget graphics and color and lines. How about "hello world"? I mean, Woz did it with paperclips and shiny gum wrappers, at least so I'm told.
That's where things go off the deep end. It's like there's these simple baby steps to get to a UART, but video? That's...just not in the cards.
Ben Eater did a nice series on getting a VGA video signal using discrete components. It's really informative.
Demonstrably video is very difficult. Apparently anyone that can decipher a tool like KiCad can come up with a 8-Bit processor and a UART. But nobody, anywhere, is doing video.
The few that are doing anything are these retro clones striving to duplicate C-64s, trying to step above the hobby market and break out with a commercial product. But even they struggle.
I just find it curious how this last step seems so out of reach.
The problem may simply be there's nothing to display video on. An 8-bit machine driving even a VGA monitor is asking an awful lot, and I don't know what it takes to convert composite video to run on a modern display, either a VGA or HDMI. I would think if someone came up with THAT circuit, composite in, VGA out, as a "black box", something the board designers could plug in to, like the old RCA boxes we used to use tuned to Channel 3, then maybe that's the breakthrough thats missing from the community. They they could fall back on the old composite circuits from that past.
But, nothing.
Happy to discuss further, email is in profile.
[0] https://en.wikipedia.org/wiki/Nascom_(computer_kit)
https://gigatron.io/ "... low resolution video had come within reach of our design, without adding chips. This was possible by taking the unconventional step of bit-banging video signals from software, instead of designing a standard video generation circuit. ..."
https://basicengine.org/ "The VS23S010D-L ... is a static RAM chip ... (that) comes with a video controller. ... It comes with 128 kB, some or all of which can be used as a frame buffer ... has a "block move" feature, more commonly known as a blitter. It allows you to copy sections of video memory ... provides a dramatic performance boost in ... text screen scrolling and rendering of tiled backgrounds."
http://uzebox.org/wiki/index.php?title=Main_Page - Uzebox - "retro-minimalist homebrew game console. ... video sync generation, tile rendering and music mixing is done realtime by a background task ... easy and fun to assemble and program ... contains only two chips: an ATmega644 and an AD725 RGB-to-NTSC converter."
http://www.breatharian.eu/hw/atx80/index_en.html - " VGA and PAL/NTSC video signals are generated by software running along with the BASIC interpreter on the same processor."
https://create.arduino.cc/projecthub/michalin70/the-arduino-... - Photos and schematics show the Arduino plugged into a solderless breadboard along with a few passive components to mix the software-generated video signals from the Arduino pins,