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I've bought some Yamaha YM2413 sound chips and now I'm trying to put one into a PAL SMS 2. I've basicaly copied the circuit of the Mark III FM expansion module (http://www2.odn.ne.jp/~haf09260/Mark3/Fm70.htm). It works well except for one game: Time Soldiers. For some reason the FM chip is not detected and all sound comes from the PSG. I can hear FM sound when playing the game on Meka.... Is there something special about this game? Does a japanese SMS contain different YM2413 support logic to a Mark III + FM module?

smsfm.jpg (108.61 KB)

A lot of games only attempt to detect/use the FM chip if the system is Japanese. A language mod might be in order. Unfortunately, it'll also change the text in a lot of games...

Time Soldiers doesn't AFAIK.
It'll be interesting to hack it and investigate why it doesn't detect the FM unit.

Great mod, by the way. You may want to create a thread to detail and finetune the procedure as I'm sure people would be interested in it.
I would fund mass production of such thing if if can be miniaturized and made in a package simple to install into regular SMS.

I ran Time Soldiers through Meka's debugger and found that, unlike all other games (I looked at about 10 others), it doesn't set bit 2 of port $3E before runnig it's FM chip detection routine (reading/writing to port $F2). Could this actually be a bug in the code?

Maxim: Do you know of any FM supporting games in particular which check the region? I'd like to test them with a flash cart.

Bock: Yes, I'm intending to produce this... If I use mostly SMD components I can probably fit it into the internal space around the expansion slot. It's going to require some crazy angular board mounting though. :)

But first I want to find out exactly what works and what doesn't.

viletim wrote

Maxim: Do you know of any FM supporting games in particular which check the region? I'd like to test them with a flash cart.

Check meka.pat. It seems only WB3 does this (I thought there were more), but there are a few games that lock up if the FM chip is/is not detected. Do you have an enable/disable switch for those cases?

What chance this can work on an SMS2? (No expansion port...)

Can somebody with a functional Mark III + FM expansion tell me if there's a huge pop sound in the audio when the power is switched off? What about the japanese SMS?

Nearly ready... I'm still waiting for the card edge connectors to arrive (may be a while yet :/ ).

The board is small enough to fit inside the SMS1 expansion area and will fit in the empty space (to the right) inside a SMS2. Installation is easy for the SMS1, just a few solder connections (for audio mixing). For the SMS2 it's a bit more complicated but no more than a typical PS2 modchip.

smsfm2.jpg (318.68 KB)

Photo

smsfm.png (10.72 KB)

Circuit Diagram

Awesome thing (looks pretty scary on the pic) !!! I wonder if you could put it into MD (I'm not sure but there may be some signals missing (JoyKill maybe))?

That's so nice viletim, the only problem is that the YM2413 is so difficult to find nowadays... Liked a lot your project! And i saw that aren't too much solder points, easy to mount :-)

Author	Message
viletim Joined: 24 Sep 2006 Posts: 191 Location: Sydney, Australia	FM Sound Upgrade Posted: Fri Oct 12, 2007 3:34 pm
	I've bought some Yamaha YM2413 sound chips and now I'm trying to put one into a PAL SMS 2. I've basicaly copied the circuit of the Mark III FM expansion module (http://www2.odn.ne.jp/~haf09260/Mark3/Fm70.htm). It works well except for one game: Time Soldiers. For some reason the FM chip is not detected and all sound comes from the PSG. I can hear FM sound when playing the game on Meka.... Is there something special about this game? Does a japanese SMS contain different YM2413 support logic to a Mark III + FM module? smsfm.jpg (108.61 KB)

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14997 Location: London	Posted: Fri Oct 12, 2007 4:25 pm
	A lot of games only attempt to detect/use the FM chip if the system is Japanese. A language mod might be in order. Unfortunately, it'll also change the text in a lot of games...

Bock Site Admin Joined: 08 Jul 2001 Posts: 8723 Location: Paris, France	Posted: Fri Oct 12, 2007 4:38 pm
	Time Soldiers doesn't AFAIK. It'll be interesting to hack it and investigate why it doesn't detect the FM unit. Great mod, by the way. You may want to create a thread to detail and finetune the procedure as I'm sure people would be interested in it. I would fund mass production of such thing if if can be miniaturized and made in a package simple to install into regular SMS.

viletim Joined: 24 Sep 2006 Posts: 191 Location: Sydney, Australia	Posted: Sat Oct 13, 2007 10:06 am
	I ran Time Soldiers through Meka's debugger and found that, unlike all other games (I looked at about 10 others), it doesn't set bit 2 of port $3E before runnig it's FM chip detection routine (reading/writing to port $F2). Could this actually be a bug in the code? Maxim: Do you know of any FM supporting games in particular which check the region? I'd like to test them with a flash cart. Bock: Yes, I'm intending to produce this... If I use mostly SMD components I can probably fit it into the internal space around the expansion slot. It's going to require some crazy angular board mounting though. :) But first I want to find out exactly what works and what doesn't.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14997 Location: London	Posted: Sat Oct 13, 2007 11:36 am
	viletim wrote Maxim: Do you know of any FM supporting games in particular which check the region? I'd like to test them with a flash cart. Check meka.pat. It seems only WB3 does this (I thought there were more), but there are a few games that lock up if the FM chip is/is not detected. Do you have an enable/disable switch for those cases? What chance this can work on an SMS2? (No expansion port...)

viletim! Guest	Posted: Wed Oct 24, 2007 1:01 pm
viletim! Guest	Can somebody with a functional Mark III + FM expansion tell me if there's a huge pop sound in the audio when the power is switched off? What about the japanese SMS?

viletim Joined: 24 Sep 2006 Posts: 191 Location: Sydney, Australia	Posted: Mon Nov 19, 2007 4:17 am
	Nearly ready... I'm still waiting for the card edge connectors to arrive (may be a while yet :/ ). The board is small enough to fit inside the SMS1 expansion area and will fit in the empty space (to the right) inside a SMS2. Installation is easy for the SMS1, just a few solder connections (for audio mixing). For the SMS2 it's a bit more complicated but no more than a typical PS2 modchip. smsfm2.jpg (318.68 KB) Photo smsfm.png (10.72 KB) Circuit Diagram

TmEE Joined: 31 Oct 2007 Posts: 855 Location: Norway (used to be Estonia)	Posted: Tue Nov 20, 2007 2:35 pm
	Awesome thing (looks pretty scary on the pic) !!! I wonder if you could put it into MD (I'm not sure but there may be some signals missing (JoyKill maybe))?

Rony_ket Joined: 09 May 2007 Posts: 137 Location: Sampa, Brazil	Posted: Thu Nov 22, 2007 12:48 am
	That's so nice viletim, the only problem is that the YM2413 is so difficult to find nowadays... Liked a lot your project! And i saw that aren't too much solder points, easy to mount :-)

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