Is it possible to build a version of the Retrovision using a Gameboy Color? I don't have the parts, but I am curious to know if it is all that different.
A Wide Boy or Retrovision that can play Game Boy Color-exclusive games couldn't be made for the NES without losing a lot of picture quality. It worked for the original Game Boy because the original Game Boy's PPU outputs 2 bits per pixel and NES tiles are 2 bits per pixel. The Game Boy Color PPU, on the other hand, outputs 5 bits per channel, 3 channels per pixel. Notice that the version of the Wide Boy that takes GBC games is for the N64, not the NES. The problem of transforming GBC graphics to fit over the PPU bus would be roughly comparable to the problem of making a TV tuner for the NES.
Thanks, tepples. I have been curious about that since the Retrovision came out. What about the SNES? Is that limitation why they never did an official Super GameBoy 3?
Unlike the NES, the Super NES uses VRAM in the console. All pixels have to be pushed to the console using DMA during vertical blanking. An ordinary 160x144 pixel frame at 2 bits per pixel is 5760 bytes, which is near the 6 KiB/frame practical cart-to-VRAM transfer speed that I've read for the NTSC Super NES.