It's not specifically due to the patents expiring. It just so happened that I'd already started on the pinout for the Holly chip a few years ago when I did those tests on the NAOMI...
http://assemblergames.com/l/threads/nao ... ect.48293/ We already had the VA0 schematics that "l_oliveira" so kindly uploaded many years ago, but I was trying to confirm every pin on the Holly chip against the real NAOMI board (because it's quite hard to read some of the numbers on the VA0 schematic.)
I started looking at that stuff again the other day for whatever reason, mentioned it to Mr [RDC], and it turns out that he'd already done a fair bit of work on it too. lol
So, in only a matter of days, he has already stripped down the VA0, VA1, and even the VA2.1 DC motherboards, and made completely re-drawn PDF schematics for each version, including all of the passive components. :o (that was while he was still working on some stuff for the HDMI boards btw - he's a machine. lol)
The new DC motherboard will have to use the Holly chip, as I haven't seen anywhere which sells new-old stock chips that still have the BGA balls etc.
You can buy the SH4 "new" on AliExpress etc. but since we'd be pinching the Holly chip off an original board anyway, we might as well use the whole lot. That does mean getting the chips re-balled, or doing that ourselves, but it will be worth it.
We're looking to get the first board made as a "stock" spec one, just so we're sure that everything is working 100%, and then we can move on to making designs with added features.
I believe [RDC] has already added the footprints for the extra RAM chips though, so that will introduce the possibility of future NAOMI cart / "GD" emulation on a separate add-on board (kind of like the GD-Emu, but the games will likely get loaded from SD / USB into a chunk of SDRAM first.)
Most NAOMI carts do have some "encryption", but all of that seems to have been cracked now, and the info is in the MAME sources.
I never actually tried running a cart from the FPGA when I had it hooked up that time, as I'd moved on to the HDMI project and other things by then.
It did at least let me figure out some of the basic address decoding and connector pinouts on the NAOMI though, and [RDC] will be stripping down a NAOMI board soon to do the full schematic for that as well. :o
With the new DC board, we should be able to put faster RAMs on there too, so may get a little bit more of an overclock out of it. The thought of doing the widescreen / 60 FPS patches on many games, and patching them for slightly higher-res video output will be great.
(if that's doable? - I know KallistiOS has a working "800x600" code example, so that will at least give a bit of a boost to the output resolution compared to 640x480.)
I did do most of the schematics and PCB layout for a new N64 motherboard too, but I never finished it 100%, nor actually sent of for any PCBs to be made. It would be funny to stack the boards in the same system, and then have a console that could play DC, N64, and NAOMI games loaded from SD card, and with up-scaling HDMI / Component output. lol
It does all sound a bit crazy atm, but I'm confident that [RDC] will have the new motherboard PCB layout done within the coming weeks. Right now though, we're absolutely determined to get these HDMI boards released this year.