MESS 0.137 is out!

Hi

I'm proud to announce my little personal contribution to the best emulator project in the world.

Since a bit after chipsounds 1.0 was released, I started contributing some of my recent research to the open source 'MESS' project on the sound front. My contributions are "without strings attached" as I feel that the research in MAME/MESS is crucial to the good preservation of the history of computing. Besides, the accumulated knowledge in there will surely outlive me :)

"0.137

New System Drivers Supported:
-----------------------------
- Casio PV-1000 [Wilbert Pol, plgDavid]
(...)

System Driver Changes:
----------------------
- [SCV] Implemented upd177c audio. [plgDavid]"


The SCV audio still needs work, so that's not the last effort I will put into it. I've also tweaked the Arcadia 2001 audio code and made it much closer to the real thing. I also plan on revisiting a few other "drivers", when I get the chance, namely the VIC-20.

The MAME/MESS Teams members are very passionate and knowledgeable. I want to take the moment to greet Wilbert Pol, kevtris and Lord Nightmare especially, and to thank them for their time and near infinite knowledge.

Get it NOW

The SID's non-monotonic DAC

That picture is from a 6581R4AR. A Simple ADSR glide on a 50/50 Pulse set at highest freq.
This is going to be fun to emulate....

http://masteringelectronicsdesign.com/an-adc-and-dac-differential-non-linearity-dnl/

Ultimate 2532(or 2352) PROM MegaCart!!! ... kinda

While visiting my favorite local Electronics Surplus Store I came across this odd 24 pin fake IC to IC cable, which gave me a cool idea. One very common (and boring) tasks in my line of work is doing adapters to run ROMs (custom and whatnot) on the real hardware for analysis. This setup makes it pretty easy (and solderless) to try stuff around, especially difference in CPU<->BUS<->ROM handshaking signals like !CS !CE, !E whatever, and also configuration of adress lines.

Systems that typically use such 24pin ROMs include
VIC-20
ATARI 2600
MPT-03 - Arcadia 2001 clone(pictured)
Odyssey2

This particular breadbreadboard setup allows me to quickly "audition" up to 16 different 4KB Arcadia ROMs using DIP switches.

That big mysterious gate array

Analyse.. don't Destroy (a Casio PV-1000)

I'm not a console collector nut, I'm a audio chip collector nut. There are countless game consoles and computers out there that I dont care much about because they all contain the same chips. (AY-3-8910 is nice, but you can only have so many of them).

What I'm looking to acquire at this point are the most obscure ones which contain custom/unique sound generating chips. You've heard about the CASIO PV-1000 before?

Don't worry, only the most die hard console collectors did. And they would die for it too. There are very very few such consoles out there and I got mine a bit by chance, and it was an impulse buy.

At 300$ (ebay), you just can't afford to ruin it can you? (I'm not a movie producer). And I look forward to its resell value once im done with it. Thats where the challenge comes in... how do I take a device that comes with just a NTSC-J RF adapter and get good enough audio results with it? (the RF channels on North american and Japan dont match... dont try)

The closest I got to getting a picture/sound from the default unit as is was to use a ANALOG/DIGITAL USB TV tuner, which had by chance a NTSC-J mode:

Not that bad, but, the audio was horrendous, and really not usable for my tests. However I've hacked nearly all my consoles in order to have separate composite video/audio from RCA jacks, so on top of some test equipement, i've got a few hunches on how to solve this cleanly.

the RF box is tied to the main motherboard in a very clean way:

A few minutes with my multimeter, from top to bottom:
1)9VDC (current for the amplifiers in the RF sections i assume)
2)GND
3)Composite Video Out.. YAY!
4)GND (same as 2)
5)Audio Out...  w00t!

Connecting Aligator jumpers to truncated ends of a RCA and to the pins 3,4 and 5 did provide me with a temporary solution, but surely isnt very practical for a longer term analysis.

Oups, where did the RF box go? (in a safe place in case I resell it and the buyer really is after lots of  pain and suffering).

Much better.
 From the outside:

Enjoy the OK quality outputs:

Meet my new friend the logic analyser!

Its time to step my game up. So I've decided to acquire the immese value for money Saleae Logic Analyser. This baby will allow me to analyse and record a bunch of stuff that really cant be handled with a sound card and an oscilloscope alone. (namely serial digital audio prior to being sent to DACs)

As a test to see if everything works, and that i can get sufficient time resolution on this, ive done a simple setup which consists in a 4Mhz clock and a Hex inverter (74LS04). I done my recording test using 24Mhz on my MacBookPro's USB2 port. And im quite happy with the results. Not bad for 15 minutes of unboxing the thing!

These are not the chips you're looking for

[EDIT dec7th 2009] the wikipedia page has been corrected!Thanks!

According to wikipedia there is a VRC6 chip inside a North American Nigel Mansell "World Challenge" cartridge. Well no, there isn't. And there's no such thing as "World Challenge" either, only "World Championship" same difference.

Looks like Ill have to dig up the big bucks for a Japanese Castlevania 3 cart.