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thejpster / monotron

A simple 8-bit home computer style application for the TI Tiva-C Launchpad
Apache License 2.0
191 stars 9 forks source link

RGBI video support #47

Open thejpster opened 5 years ago

thejpster commented 5 years ago

While we don't really have the memory or the SPI outputs to add an extra channel for true 16-colour RGBI output, there is a hack we could do.

We could apply the I bit on a per line basis. This would basically involve lifting a GPIO pin before the visible area and dropping it after the visible area. We would need a circuit where intense black was the same level as non-intense black (like on a ZX Spectrum), but we would then only need 1 bit per line, and one conditional GPIO write per line.

I need to research a circuit for doing RGBI TTL video.

thejpster commented 5 years ago

We'd need to turn the border off otherwise it'll be stripy.