I like how you've implemented your assembler... I think I'd go exactly the same way about it. This is the quickest and easiest way to get as close as possible to BBC BASIC's wonderful built-in assembler.
Very impressive, all the processing time used to output a display reminds me of the Sinclair ZX80 I used to own, it had to turn off the display to process anything else, the only time it would appear was to prompt for an input, but it would flicker off even as you typed a character. Later they realised with interrupts you could process other code while the screen was updating above and below the border, hence a slow mode option was introduced on the ZX81 where the display remained on allowing moving objects and games. Clever programmers managed to implement the same thing on the ZX80, but it had to be done entirely with very precise software timing. Amazingly we got a few flicker free games even on the ZX80.
Amazing project! I found the magic-1 and the homebrew CPU ring a few years ago too, and since I've wanted to make my own too. But I havent't gotten around to it yet.
This is inspiring. I have too many projects at the moment to resurrect my TTL CPU but I’ve been toying with the idea for a while. I like your approach for the brains of the CPU. I used a 74181 + microcode and I think that limited my prospects. I think I will redesign the ALU around my requirements and ditch the 74181 rather than be limited by it. Looking forward to more on this.
he discussed it around 5:35. essentially the instruction is split into its op code and operand and he uses a lookup table stored in ram (he says ram but rom would make more sense) with all precomputed values for all instructions. Control lines also come from rom he said, so im guessing that when he flashes the program to rom it has to be pre processed. i can only speculate on this second point, but im making a 4 bit processor right now and am handling it a similar way
For video you could implement h/w accelerated lines doubler as totally external part, not complicating/poluting CPU board, which could be implemented as cheap 10x10cm PCB. Or just bitbang RS232 for external terminal. That could simplify thing for amateurs to reproduce.
Nice work! I tried my best to squeeze the 74LS series of chips to do true VGA @ 640x480 but they just couldn't zoom zoom. I did order some chips from futurlec that were significantly faster (100mhz or so i think?) and were supposed to be TTL compatible, but I had trouble getting them working properly. Moved on to other projects after that.
This CPU is different Harvard architecture so strictly saying no, but it's possible to write 6502 interpreter in software so CPU will act as a micro-code CPU. In this case this bread board computer can be (re)targeted to any CPU just matter of execution speed.
![“อาร์ต พศุตม์” เกือบเอี่ยวทุกคดีดัง เอ๊ะไว้ก่อน ไม่มีอะไรได้มาง่ายๆ | แฉ 16 ต.ค. 67 [2/3] | GMM25](http://i.ytimg.com/vi/0Gx-0-kUBv8/mqdefault.jpg)
I like how you've implemented your assembler... I think I'd go exactly the same way about it. This is the quickest and easiest way to get as close as possible to BBC BASIC's wonderful built-in assembler.
Amazing work! Please make update videos with more frequency!
Very impressive, all the processing time used to output a display reminds me of the Sinclair ZX80 I used to own, it had to turn off the display to process anything else, the only time it would appear was to prompt for an input, but it would flicker off even as you typed a character. Later they realised with interrupts you could process other code while the screen was updating above and below the border, hence a slow mode option was introduced on the ZX81 where the display remained on allowing moving objects and games. Clever programmers managed to implement the same thing on the ZX80, but it had to be done entirely with very precise software timing. Amazingly we got a few flicker free games even on the ZX80.
This is most interesting and informative
Amazing project! I found the magic-1 and the homebrew CPU ring a few years ago too, and since I've wanted to make my own too. But I havent't gotten around to it yet.
This is inspiring. I have too many projects at the moment to resurrect my TTL CPU but I’ve been toying with the idea for a while. I like your approach for the brains of the CPU. I used a 74181 + microcode and I think that limited my prospects. I think I will redesign the ALU around my requirements and ditch the 74181 rather than be limited by it. Looking forward to more on this.
Great work !! I've came from your older video and I'm really curios to see next iterations of your project wish you luck and enjoyment in your journey
Fabulous! Looking forwards to the seeing the PCB version!
Nicely done, and good luck with the PCB version!
Actual details of CPU are very interesting command set and timings. And also fractal battle royal to compare with 8bit big brothers!
I love this!!! So so neat! I wish I had the knowledge to do a project like this! Until then, I enjoy videos like this very much!
Well done Matt. Excellent presentation.
An excellent video, honey! I'm so proud of you 🥰
very nice idea , your architecture cpu is good idea , data=prog data +address bus and with pixel bus 👍
Very cool. But with so few chips, where is the instruction fetch, decode and execution happening?
he discussed it around 5:35. essentially the instruction is split into its op code and operand and he uses a lookup table stored in ram (he says ram but rom would make more sense) with all precomputed values for all instructions. Control lines also come from rom he said, so im guessing that when he flashes the program to rom it has to be pre processed. i can only speculate on this second point, but im making a 4 bit processor right now and am handling it a similar way
@@liaminblue9984 oh sounds interesting
Brilliant! Well done, Sir.
This looks clean!
Nice work. IBM built a computer nicknamed Can't Add Doesn't Even Try or Cadet. It didn't have an ALU and used look up tables.
For video you could implement h/w accelerated lines doubler as totally external part, not complicating/poluting CPU board, which could be implemented as cheap 10x10cm PCB. Or just bitbang RS232 for external terminal. That could simplify thing for amateurs to reproduce.
Nice work!
I tried my best to squeeze the 74LS series of chips to do true VGA @ 640x480 but they just couldn't zoom zoom. I did order some chips from futurlec that were significantly faster (100mhz or so i think?) and were supposed to be TTL compatible, but I had trouble getting them working properly. Moved on to other projects after that.
I think this project has already been done by many people)) I expect to see Ternary computer
Interesting - you show registers A, X, Y as 4bit inputs, but 8bit output. How?
List of opcodes and the microcode they are decoded into, please please please!!
Very nice!
Is it possible to make the CPU binary compatible with 6502?
This CPU is different Harvard architecture so strictly saying no, but it's possible to write 6502 interpreter in software so CPU will act as a micro-code CPU. In this case this bread board computer can be (re)targeted to any CPU just matter of execution speed.