Yep! It’s my own design. Started with the Ben Eater kit. (Highly recommended) The most complex part is how the VGA circuits share the RAM with the CPU.
@@thecodesorcerer Ah yes, the video RAM memory interleaving, effectively reducing the clock speed to 1 MHz. even cycles for executing code, and odd cycles for handling video. Most 6502-based computers have this. Also effectively ruling out any form of overclocking too.
CPU gets RAM when clock is high, video when low. It’s VGA instead of composite, so video is 1/16tg the VGA clock. About 1.57MHz. Apple II runs at 1.024MHz. Has caused me so many challenges with Apple II compat. Game controllers, disk, sound all depend on counting cycles.
@@thecodesorcerer Yes, most of the machines from that era have massive compromises to save on parts and cost. the 80's were brutal as far as competition went. I believe there were designs based on 6502 with separate video controller and memory etc, but they were extremely expensive and always remained a niche product.
I actually went for Apple II software compat because the video hardware was so simple. Atari, C64 had custom video chips. Apple used off the shelf logic.
Amazing work!! Beautifully done. I worked on something similar about 10 years ago, I got the video + vga + clock done, but then switched to another project. I’ll check how you divided clock to 1mhz :)
Kareteka at 150% speed is honestly the only way to play it. Very impressive work.
This just popped up in my recommended. Looks good, is this completely your own design? I know Ben Eater also has a breadboard 6502 project.
Like.
Yep! It’s my own design. Started with the Ben Eater kit. (Highly recommended) The most complex part is how the VGA circuits share the RAM with the CPU.
@@thecodesorcerer Ah yes, the video RAM memory interleaving, effectively reducing the clock speed to 1 MHz. even cycles for executing code, and odd cycles for handling video. Most 6502-based computers have this. Also effectively ruling out any form of overclocking too.
CPU gets RAM when clock is high, video when low. It’s VGA instead of composite, so video is 1/16tg the VGA clock. About 1.57MHz. Apple II runs at 1.024MHz. Has caused me so many challenges with Apple II compat. Game controllers, disk, sound all depend on counting cycles.
@@thecodesorcerer Yes, most of the machines from that era have massive compromises to save on parts and cost. the 80's were brutal as far as competition went. I believe there were designs based on 6502 with separate video controller and memory etc, but they were extremely expensive and always remained a niche product.
I actually went for Apple II software compat because the video hardware was so simple. Atari, C64 had custom video chips. Apple used off the shelf logic.
Amazing work!! Beautifully done. I worked on something similar about 10 years ago, I got the video + vga + clock done, but then switched to another project. I’ll check how you divided clock to 1mhz :)