My first experiments in generating composite video signals on a PIC microchip were in 2004, I started very simple, the 5x5Pixler, a Rorschach style picture generator, and a 1 player pong game.
During the pandemic 2020 I decided to go back and do some more video stuff, this time on an even more limited PIC, the 12F508 (I will write more about this very base-line chip and why I like to use it.). With only 25 Bytes RAM, 512 Words (12 Bit, equal to 768 Bytes) ROM and an internal clock frequency of 1 Mhz, I knew I would only be able to program (in assembly language, of course!) a very simple game, similar to the first LCD games in the early 80ies, with which I grew up. They all use shift-registers for the obstacles, as I did in my simplified Frogger-style game (40 years of Frogger!).
The first version was only black/white, but I managed to get 6 greyscales with a 3 Bit DA (3 resistors), giving the logs a nice '3D' effect :) The remaining pins I used for control buttons (up/down) and sound out.
I went on programming other games, animations, image generators (...). For all those chips, filled to the last byte with code, I designed (on paper) a 'game' console with almost nothing inside (only passive elements and connectors), while the 'brain' was in the cartridges, similar to Atari's GameBrain prototype. Some day I might actually build it.
Cool!
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