Probably Ben Eater's videos. But his build was too minimalist for my taste, so I designed something with expansion in mind. The first version was inspired by the RC2014, which has a backplane and everything else on separate boards, but for the second version, I added things to the mainboard to make it a functional single board computer.
Next thing I'm working on is a video output card, but it is proving extremely tricky. I also have a MIDI board in the pipeline.
I tried with an fpga, but it is difficult to get the needed features and performance at a reasonable price.
I also tried with a RP2040, and this seems to be easier, although the performance is not quite there yet.
Have you looked at the Propeller chips from Parallax?
The P1 can do retro grade graphics from very solid TV graphics through higher resolution VGA.
The P2 can drive any display, had 640x480 HDMI capability built in, and analog video of all kinds is very well supported.
It would work in both of the classic ways for you. One way is to have it read the actual video RAM when the CPU allows that, and the other would be for it to have its own video RAM and the CPU communicates to it in some fashion.
That’s really impressive. Once there is video beyond a terminal I can envision the project attracting so many more persons. My 1200xl is not going to live forever and I’m losing hope that revive machines is going to happen.
Some things already exist that can act as a dumb terminal, ie put the serial output to an VGA or HDMI screen, but I also want to be able to do graphics and stuff.
Also, the keyboard input from a PS2 keyboard already exists and works fine, so the video is really the last missing piece.
Just curious:
TTL, like an Apple
Custom chip from say, TI?
Microcontroller?
FPGA?
The P1 can do retro grade graphics from very solid TV graphics through higher resolution VGA.
The P2 can drive any display, had 640x480 HDMI capability built in, and analog video of all kinds is very well supported.
It would work in both of the classic ways for you. One way is to have it read the actual video RAM when the CPU allows that, and the other would be for it to have its own video RAM and the CPU communicates to it in some fashion.
Damned impressed with the project TBh
Also, the keyboard input from a PS2 keyboard already exists and works fine, so the video is really the last missing piece.