Extended Audio ideas

arfink · Post by **arfink** » Mon Jul 17, 2006 9:21 pm

Hey all, I am sure that most of you probably know that there were some cool famicom games that utilized special extended audio. I am sure most of you also know that the NES had a mysterious expansion port on the bottom of the system. This expansion port can accept an audio input, while those famicom carts with extended audio features ouput audio on a certian pin (gotta chek which one... edit will be coming soon, I hope) I have already got plans to build my own dongle to work with a special famicom to NES converter which will rout this extended audio through the expansion port. However, while this will generally work OK on the regular "toaster" style NES systems, it will not work on most NOACs. I would be loathe to build a portable and then not be able to have extended audio. So, I have been developing a simple mixer circuit which could be added into my NESp in order to have this special extended audio. I am looking for some people who would like to collaberate or for opinions on how this should be done. It would be really cool if the NES community could resolve upon a standard way of doing this, so that potentially, some time in the future, a manufacturer (not me, don't ask! maybe Messiah?) could make these adaptors and dongles and they could then be compatible with NESp's that people would make here. Also, then game companies who want to make things similar to the Generation NEX can incorporate this feature as well.

I also intend to post this same thing at some point to the NESDEV forums, as a standard method of doing this would have to be agreed upon to make it easy and more widespread.

Tell me what you think guys, if no one is interested I could let this die, but I think this is important and cool because I am sure that there are many NES gamers who want to get into Famicom gaming badly but lack the knowledge and/or the adaptors to make it work.

Also, I have metioned this many time now in many different places, but does anyone have a 60 pin female famicom cartridge adaptor I could buy?
Anyone at all? Please, I really need this part to move this development forward. Thank you.

Edit: Here is a link to a post I have made on the NESDEV forums, in case you would like to discuss tech stuff there instead:

http://nesdev.parodius.com/bbs/viewtopic.php?t=1818

Post by **gannon** » Mon Jul 17, 2006 10:21 pm

Why make a 2nd topic about this?
http://benheck.com/phpBB/viewtopic.php?t=13152

arfink · Post by **arfink** » Tue Jul 18, 2006 6:29 am

Becuase nobody seemed to notice my first one, and because I am lazy and didn't want to edit my first topic, and also because I wanted to add in my request for the famicom connector. Is it a huge problem? Because I could just have the post deleted and work with my old one. Also, the issue of standardizing this should probably be given some better consideration in a new post, don't you think so? I dunno, maybe I'm just rude and don't know it...

edit: ok, maybe this isn't too hard, I should do it more often... anyhoo, I have found a part on Jameco that appears to be the right kind of connector to use in the NES expansion port, I will have to check it out a little closer to be sure though. As long as a dongle would be built for te extended audio, it would be cool to add some other features in there as well. I was thinking of maybe routing lockout chip data through the expansion port so a cartridge converter would work better and could be made smaller, and that NMI interrupt for freezing games could be incorportaed as well. I also had another strange idea late last night, how about making an audio input for your CD or MP3 player? I was thinking of games like Tetris, where you ould turn off the in-game music and then play your own music instead. I know, its kinda odd and not exactly extremely useful, but it would be kinda cool just to do it.

TitaniumHamster · Post by **TitaniumHamster** » Tue Jul 18, 2006 12:49 pm

arfink wrote:I also had another strange idea late last night, how about making an audio input for your CD or MP3 player? I was thinking of games like Tetris, where you ould turn off the in-game music and then play your own music instead. I know, its kinda odd and not exactly extremely useful, but it would be kinda cool just to do it.

By "odd and not exactly useful", I'm almost positive you really mean wicked awsome and by far the most awsome idea ever. I hope you figure out how to do this, cuz I'd be quick to tear up my NES to do so.

arfink · Post by **arfink** » Tue Jul 18, 2006 2:40 pm

Actually, the reason I am making this a dongle is so that you don't have to rip your NES apart!

cool huh?

Actually, this dongle is multi pupose, and I would use it with a famicom adaptor that I am also working on so that you can play famicom games, like Akumajo Densetsu on the NES and the special sounds will play properly. I did want to see if people could agree on a standard, though, so that, say, all famicom to NES adaptors will use the same expansion port pin for audio so that the dongles gan all be made exactly the same way. I know that ordinarily this would not be a huge deal, but some people have those connectors made from 2 floppy cable plugs, so maybe there are certain expansion port pins that work better than others. I dunno, need feedback on this one.

arfink · Post by **arfink** » Tue Jul 18, 2006 6:12 pm

Does anyone know for certain what the pitch of the pins on the expansion port are? I have guessed, but I think I may be off by a bit. If nobody knows, can someone teach me how to measure the pitch? I am just comparing the expansion port connector to other connectors I have got. If the pitch is what I think it is (.1" or so) then the connector issue is resolved. Unfortunately I have a feeling that this is not the correct pitch.

At this point I am looking at parts for the project and also making some diagrams. When I can accomplish something really meaningful then I will post pics of these drawings.

Post by **gannon** » Tue Jul 18, 2006 8:09 pm

Code: Select all

         |*      \
VCC  >01]        [48<  VCC
VEE  >02]        [47<  VEE
AIN  >03]        [46]  --
/NMI  [04]        [45>  C.2
CA15  <05]        [44>  C.1
(51)  [06]        [43>  C.0
(52)  [07]        [42]  (16)
(53)  [08]        [41]  (17)
(54)  [09]        [40]  (18)
(55)  [10]        [39]  (19)
/C2R  <11]        [38]  (20)
C1.1  >12]  EXP.  [37>  /C1R
C1.3  >13]  PORT  [36>  C1.4
/IRQ  [14]        [35>  C1.0
C2.2  >15]        [34>  /C1R
C2.3  >16]        [33>  C1.2
/C2R  <17]        [32]  D0
C2.4  >18]        [31]  D1
C2.0  >19]        [30]  D2
C2.1  >20]        [29]  D3
VOUT  <21]        [28]  D4
AOUT  <22]        [27]  D5
VDD  <23]        [26]  D6
4MHZ  <24]        [25]  D7
         |_______/

Pins 1, 2, 3, 4, 21, 22 look to be the most important, although pins 6, 7, 8, 9, 10, 38, 39, 40, 41, & 42 would be interesting too.
http://nesdev.parodius.com/NES%20hardwa ... 0guide.txt

arfink · Post by **arfink** » Thu Jul 20, 2006 5:12 am

I agree, and that document is what spurred this insane idea. BTW, I am looking to either build or modify a famicom-nes cartridge converter so that the sound feature of the dongle can be properly built. Anyone have that 60-pin Famicom cartridge connector yet? Or does someone have a pre-built cartridge converter that I could buy? Don't be shy, I do have money to pay you back with...