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Nice! What’s the new mapper you’re using? Is it available as an IC or does it use FPGA or something?
by namuol 1y ago
Nice! What’s the new mapper you’re using? Is it available as an IC or does it use FPGA or something?
- zeta0134 1y agoIt's an FPGA mapper made by Broke Studio, detailed here if you're curious: https://github.com/BrokeStudio/rainbow-net/blob/master/NES/mapper-doc.md https://github.com/BrokeStudio/rainbow-net/blob/master/NES/m... In terms of capabilities, graphically it's something like MMC5 (8x8 attributes and a bunch of tile memory) while sound wise it's almost exactly VRC6. The real nifty feature though is ipcm: it can make the audio available for reading at $4011 It turns out the APU inside the NES listens to writes to $4011 to set the DPCM level, which many games use to play samples. By having the cartridge drive it for reading, I can very efficiently stream one sample of audio with the following code: inc $4011 So I just make sure to run that regularly and hey presto, working expansion audio on the model that doesn't normally support it. It aliases a little bit, but if I'm clever about how I compose the music I can easily work around that.