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Video card for "nanocomputer"

A project log for Homebrew CP/M-computer powered by Arduino Nano

Homebrew computer under CP/M with TV Out and PS/2 keyboard powered by Arduino Nano

Alexey VoroninAlexey Voronin 12/21/2020 at 21:010 Comments

I started a companion project to expand the graphics capabilities of my "nanocomputer". Another Arduino Nano acts as a video card that provides a monochrome image output on TV with a resolution of 320 x 244 (like the Sega Genesis, 240p format)! And this is not drawing lines in the demo format, this is a module with  pixel video memory - I use SPI RAM 23K256 as it. As a basic option, I want to make time-divided access to this chip - during 244 active pixel lines, the video processor owns it, and the remaining 68 lines - the memory can be used by the main processor. Well, now I just for "proof-of-concept" implemented control via UART. This is the picture my video card gives out after loading via UART into video memory - I converted a screenshot from the FoxyLand game for Sega Genesis to monochrome - the picture was taken using a TV tuner (I dug up my old 609 Beholder in the bins):


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