Color (sic) Palette DAC

No luck with the SDRAM at this point - not even seeing what I expect in SignalTap on the ROM download - so I thought I'd change tack for a while and work on the Color Palette DAC block.

The YGV608 Application Manual expands on the top-level block diagram in a few of the sections, and the Color Palette DAC is one example where I hadn't quite got the interface signals correct until I read this section in more detail. I've now implemented the DAC memory block and have initialised the first 32 entries using data taken from the NCV1 code.

Here's what I have now, with colours more akin to the actual start-up screen (I've hard-coded the border colour to blue for now)...

Simulation using palette RAM look-up

Next up for simulation is the pattern name table (tilemap) RAM block. If I can seed that from an NCV1 memory dump (for example) I should be able to then generate an actual frame from NCV1.

But I don't want to get too far ahead of the state of the MiSTer side of things... might have to reach out for some help on the SDRAM issue. It should be quite simple given I've ripped it all from the Gauntlet core...

UPDATE: now that looks better on MiSTer...