I have made a couple of builds that add PWM on the 18-bit DAC to get 24-bit color for the cores that need it. This is for any non-scaled signals that use the VGA port on the IO board. It works by quickly alternating between two different color values to get a color in between. The PWM happens very fast so it can be done even for 640 wide images.
We have been testing it on the Mister FPGA discord, here are some pictures:
RGB SCART:
Active Y/C S-video PWM off:
Active Y/C S-video PWM on:
I have included a build for N64, PSX and Saturn, PWM is always on in these builds, no settings needed.
Here is my fork of the N64 core with the PWM changes: https://github.com/Jokippo/N64_MiSTer_PWM
It seems to work quite well and may be a good alternative to using direct video or buying a new 24-bit IO board. For now, it looks like this won't be included in the MiSTer framework.
edit: Updated N64 core to most recent source. PSX core had some red color shift on component, might be a bit less on this build.
edit 13/02/2024: Update to latest N64 changes and disabled PWM for scaled output as it was causing jitter.
edit 15/02/2024: Added Groovy core with PWM.
edit 28/02/2024: Update n64 and add Saturn Core.
edit 14/03/2024: Update n64 core, PWM is included as standard in Groovy now so you can download that from the official Github.
edit 08/04/2024: Update of all 3 cores to latest source.
edit 04/05/2024: Update all 3 cores.
edit 07/05/2024: N64 core had some vertical green lines on HDMI output, should be fixed now.