General questions about NES clones

infiniteneslives · Post by **infiniteneslives** » Sat Sep 03, 2011 3:30 pm

MottZilla wrote:If you're going to start enhancing the NES, another 6K of WorkRAM ($800-$1FFF) would be nice. DMA from CPU bus to PPU bus would be handy too. While we are at it, overclocking without altering audio generation would be very neat as well. Other useful things would be a built in PPU based IRQ, like MMC5's scanline counter functionally. Oh another 2K for 4 nametables total would be nice to include as well.

If you really wanted to, (with the exception of overclocking) couldn't you do most of this on a cart with an unmodified NES?

tokumaru · Post by **tokumaru** » Sat Sep 03, 2011 4:08 pm

I guess... Many mappers already have extra RAM and PPU-based IRQ. Some have more VRAM for nametables. DMA is probably doable too (it would be pretty cool to be able to transfer 1000+ bytes to VRAM per VBlank!).

Overclocking is the only feature in that list that would improve existing games, but it's also the only one that can't be put in a cart. You could have another processor in the cart though (a second 6502 maybe), running faster than the one in the NES, but only new software would take advantage of it.

Post by **tepples** » Sat Sep 03, 2011 6:07 pm

tokumaru wrote:[In a mapper,] DMA is probably doable too (it would be pretty cool to be able to transfer 1000+ bytes to VRAM per VBlank!).

Dual-ported VRAM/WRAM is possible on a cart (just ask any emulator author who has got MMC5 games to work), but it's probably too big to fit on a CPLD.

Overclocking is the only feature in that list that would improve existing games, but it's also the only one that can't be put in a cart. You could have another processor in the cart though (a second 6502 maybe), running faster than the one in the NES, but only new software would take advantage of it.

Think of the essay one could write about how that would improve Super NES games like Kirby and Super Mario RPG.

As for the TG16: If only it were cheaper to get one around here.

tokumaru · Post by **tokumaru** » Sat Sep 03, 2011 6:20 pm

tepples wrote:As for the TG16: If only it were cheaper to get one around here.

What about "If only it had been popular anywhere outside of Japan so that it was more accessible to everyone nowadays"?

The TG16 is nice and all, but it's a rarity in most places of the world. The NES, on the other hand, was so popular everywhere that it's still really easy and cheap to find consoles (even if they are clones), carts (even if they are pirates) and accessories. I believe that's one of the greatest advantages about the NES when it comes to retro consoles.

MottZilla · Post by **MottZilla** » Sun Sep 04, 2011 8:02 am

You're correct about that. It's just a shame that many clones are poorly constructed with the mentioned problems.

About the TG16/PCE, it's a shame no one has yet cloned it. Probably due to its lesser popularity and also because it would be wise to clone the CDROM too given the number of great games that are CD or Super CD. If one were to dream though, cloning the DUO but with the Super Grafx hardware and Arcade Card built in would be the coolest.

Post by **tepples** » Sun Sep 04, 2011 9:27 am

How much does a CD drive cost compared to a cart slot? And how much would it cost to get a PCE-on-a-chip ASIC fabricated including the over 2 MB of RAM on an Arcade Card?

MottZilla · Post by **MottZilla** » Mon Sep 05, 2011 8:42 am

I don't know, but given that PC-Engine DUOs often go used for anywhere from $150 to $300 I don't think price is a huge concern. I forget exactly what I paid for my refurbished DUO-R with RGB mod, over $200. There are people that would pay for a PC Engine with SuperGrafx and Arcade Card compatibility built in, so long as the cost wasn't astronomical.

Shiru · Post by **Shiru** » Mon Sep 05, 2011 9:18 am

Any ASIC production involves hundreds of thousands $ and up to millions, so a FPGA-based clone is much more realistic. This would cost few hundreds $ per unit.