NOAC (NES-on-a-chip) datasheets, development tools, demos

mark_k · Post by **mark_k** » Thu May 28, 2009 2:41 pm

Hi,

Apologies if this info is already widely known, I haven't seen it mentioned before. I was looking for datasheets and other info about NES-on-a-chip ICs, and found an interesting site. (If anyone knows of other NOAC manufacturers, please let me know!)

V. R. Technology http://www.vrt.com.tw/ make a range of chips. There are datasheets, development tools including a fully-featured emulator and examples on their web site. For convenience, I have uploaded an archive of all the datasheets and other files, which you can get from http://rapidshare.de/files/47324611/VRT_files.zip.html (the archive is about 70MB).

Development software includes a C compiler, assembler, picture conversion tool (shows what images would look like on NTSC or PAL TV, or LCD panel), emulator (EmuVT - this seems very comprehensive, so is probably modified from an existing open-source NES emulator), tools for creating your own multi-game cartridges (demo archive includes an 8Mbyte ROM image containing Sonic the Hedgehog and (ahem) lots of other titles...).

There are several interesting features from both a hardware and software perspective. Take for example the VT03 chip:

50/60Hz, PAL or NTSC selectable
Stereo sound! There are two APUs, the second is accessed in the region $4020-$4035
Optional "one bus" operation, i.e. a single ROM chip contains both PRG and CHR data. (Cartridges for the OneStation console probably use that feature.)
Timer interrupt facility, can count down PA12 or HSYNC (scanline) transitions
High-colour palette mode; according to the datasheet, there are 121 possible colours. Colours specified in $3Fxx and $3Fxx + $80
Built-in bank selection hardware, change H/V mirroring in software ($4106 bit 0)
16-colour sprites and large sprites (16 pixels wide)

The VT18 chip has RGB output (I'm not sure whether analogue or digital) for connection to TFT LCD displays. Maybe the FC Mobile console contains one of those chips? OneStation cartridges may do also. (In which case, info in the datasheets could help emulator developers support OneStation ROM images.)

There is a cool-looking development board, which has a daughter-board containing 32Mbyte SRAM, and a flash chip can be programmed using it too. That connects to a PC USB port.

Edit: The VRT_files.zip archive which I uploaded to rapidshare is no longer there, so I have uploaded the file to Fileserve: File name: VRT_files.zip File size: 70.39 MB

Edit 2: I have re-uploaded the VRT_files.zip archive to http://www.multiupload.nl/09JVN5CC9Q

Edit 3: VRT_files.zip uploaded to 4shared and Mediafire.

CartCollector · Post by **CartCollector** » Sat Jun 06, 2009 11:28 am

That's awesome. It's like the NES version of the C64 Plug-and-Play.

mark_k · Post by **mark_k** » Thu Jul 30, 2009 2:07 pm

It seems that the Messiah Generation NEX Famicom clone uses a VT03 chip! Check out the pictures at http://www.retrousb.com/NEX/NEX.html, notice the VT03 text silk-screened next to the NOAC. (The retrousb link was originally posted by bunnyboy on Nov 1 2005 in this thread.)

Maybe someone with a dev cart and one of those consoles can test whether the second APU and other features like 16-pixel-wide sprites are usable with it?

naI · Post by **naI** » Mon Jun 20, 2011 11:19 am

*bump*

Would it be possible for someone to modify the original Famicom/NES hardware to implement the extra features of the VT03? For example, drop-in reverse-engineered chips/additional chips? Maybe a homebrewer could make a demo or game that uses the additional features if it detects them.

And also, here's an interesting VT03-based plug-and-play console that utilizes the high-color mode:
http://fuji.drillspirits.net/samuri/

SkinnyV · Post by **SkinnyV** » Mon Jun 20, 2011 6:01 pm

But if someone does manage to modify the console to use it (hypothetically speaking), it wouldn't be a NES/Famicom anymore... I mean, the limitation of the NES make it what it is IMO, if there was no flickering, slowdown or more color it would be something else. At that point, why not just switch to SNES coding?

Post by **tepples** » Tue Jun 21, 2011 4:55 am

SkinnyV wrote:But if someone does manage to modify the console to use it (hypothetically speaking), it wouldn't be a NES/Famicom anymore... I mean, the limitation of the NES make it what it is IMO, if there was no flickering, slowdown or more color it would be something else. At that point, why not just switch to SNES coding?

Three things:

As I understand it, the SPC700 assembler toolchain isn't as mature.
It takes a lot more skill and effort, especially for a hobbyist, to make art that fits in with commercial Super NES releases than art that fits in with the commercial NES releases.
Game Boy Advance homebrew, with its somewhat easier to use C++ programming language, has drawn away a lot of people who would otherwise have started coding for Super NES.

qbradq · Post by **qbradq** » Tue Jun 21, 2011 5:24 am

Wow, that blows my mind

I for one am not terribly interested in these additional features, except the built-in name table mirroring control. That's kinda nice

All of my other opinions have been pre-programmed... I mean, already stated, by Tepples above.

(Think they bought that? You do realize they can still hear you, right? Nah man, that's what these parenthesis are for.)

mic_ · Post by **mic_** » Tue Jun 21, 2011 8:11 am

As I understand it, the SPC700 assembler toolchain isn't as mature.

I don't get why people say that. If you're referring to WLA-DX, then yeah, it has some peculiar syntax for a couple of the SPC700 instructions. But other than that I think it works fine. I've used it for all my SPC stuff.
And those who hate WLA-DX can use TASM.

3gengames · Post by **3gengames** » Tue Jun 21, 2011 8:23 am

mic_ wrote:
As I understand it, the SPC700 assembler toolchain isn't as mature.
I don't get why people say that. If you're referring to WLA-DX, then yeah, it has some peculiar syntax for a couple of the SPC700 instructions. But other than that I think it works fine. I've used it for all my SPC stuff.
And those who hate WLA-DX can use TASM.

Lots of people hate on a lot of development stuff saying it's incomplete and sucks when it works fine.

And as for the extra stuff, I don't care. It's still a crap clone that has extra features. I want to make console games for the NES, not some other NES clone chip with extra crap, then I'd move to SNES. If only they spent more time on getting the NES accurate instead of putting those new modes in.

Post by **Memblers** » Tue Jun 21, 2011 12:35 pm

naI wrote:*bump*

Would it be possible for someone to modify the original Famicom/NES hardware to implement the extra features of the VT03? For example, drop-in reverse-engineered chips/additional chips? Maybe a homebrewer could make a demo or game that uses the additional features if it detects them.

Sure, anything is possible, but you quickly run into the age-old Ship of Theseus question - when does it stop being an NES?

And also, here's an interesting VT03-based plug-and-play console that utilizes the high-color mode:
http://fuji.drillspirits.net/samuri/

Pretty cool to see those. That pic of that system looks like it would be (well, relatively) easy to develop on the hardware because it's using a normal 3V flash memory chip. Main thing would be having a programmer and socket that would support that type of packaging, and the patience to test your software without desoldering the chip repeatedly (a heat gun could make it easy, but could be bad for it if done repeatedly).

BTW if you're not aware of it, if that's the same one I'm thinking of, there is an emulator for that chip that was on the website of the actual company that made the clone. I only found a couple ROMs to test it with though out of curiosity, but it worked. I don't have link for it right now though. That'd be an easy way to start working with it. Emulator ran normal NES roms too (looked like an adapted version of an open source emu, IIRC).

Regarding the SPC-700 dev tools, I can say in my experience at least that I had zero problems using TASM when I wrote the SPC program for my NSF player. Only annoyance was it didn't support .incbin, but of course it has .include so that is simple to work around with a simple bin-to-.DB app (which can be automated as well). And with SNES stuff also, I can confirm that testing with ZSNES and SNES9X is 100% pointless unless you have it working on a real SNES first. bsnes sounds good though, it just wasn't around for me to use at the time.

tokumaru · Post by **tokumaru** » Tue Jun 21, 2011 2:21 pm

Memblers, I believe that the emulator you are talking about can be downloaded here (go to the 3rd page).

Dwedit · Post by **Dwedit** » Tue Jun 21, 2011 2:54 pm

Wow, this is classy, they're finally starting to use some good dumps in their pirate Multicartridges.

The emulator appears to be Nester.

Post by **tepples** » Tue Jun 21, 2011 2:55 pm

Next they'll actually start to use homebrew and give our work some exposure. We can hope...

Gilbert · Post by **Gilbert** » Tue Jun 21, 2011 6:29 pm

I think if one wants to develop a system similar enough to the Famicom that is easier to programme (in fields such as handling of mappers, IRQs and other limitations) and is more powerful, the PC Engine is a very good choice (we know that, the Super Famicom is not as close to the Famicom as this in comparison). It is essentially a beefed up Famicom without many of the annoyances present in the older console.

Post by **tepples** » Tue Jun 21, 2011 6:34 pm

That'd be a good idea if the PC Engine/TurboGrafx were actually popular here. Nintendo of America was fairly successful in its anticompetitive practices during the TG16 era. But I will agree that even the TG16 is probably more popular than any specific enhanced famiclone. It even has SMB3 as a single instruction.