New FM Enabled Power Base Converter Prototype

Here's my first prototype for an FM enabled Power Base Converter.

I had the idea to make this after seeing etim's FM sound expansion module for the SMS - why not have the ability to hear FM sound for a SMS game on Megadrive/Genesis as well?

To sum up the design, here are the major components:
-YM2413 stand-alone IC
-Altera CPLD to handle address decoding (I eventually want to implement stack initialization code in here just like on the official Power Base Converter (VHDL code attached)
-Quad Opamp to amplify the RO and MO outputs of the YM2413 and drive the SL and SR inputs on the Megadrive cartridge port

Check out the FM PBC in action in this video:

http://youtu.be/7OiDo46SAxU

As noted in the video there are still bugs to iron out in this first prototype. The most prominent bug is that Double Dragon crashes at the first level. Does anyone have any suggestions as to why this is happening?

Update 1:

I've succeeded in running mode 1 - essentially mode 1 includes an EXACT copy of the initialization code found on the original and official Power Base Converter. This particular routine sets the Z80 Stack Pointer to $DFFF.

http://www.smspower.org/forums/viewtopic.php?t=14084

This solves a number of bugs for the FM Power Base Converter. Firstly, it enables the game R-Type to load immediately without needing a special trick (see video linked below). Second, it prevents Double Dragon from crashing at the first level as seen in my first post's video. Here is the improved FM Power Base Converter in action:

http://youtu.be/Cqwwmff4zN4

will these be available for purchase?

@AlecRob

Yes, once I'm satisfied with the audio quality and can come up with a software mechanism to enable/disable the FM chip I will start selling them. Stay tuned!!!

Love it. Really looking forward to seeing this released!

I'd be happy with a simple physical switch to enable/disable.

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Originally Posted by Joe Redifer

I'd be happy with a simple physical switch to enable/disable.

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Yeah there is already a switch on my board as a last resort, but if I can manage to make it work with in software instead it'll make the labour to assemble this inside a cartridge shell much easier (i.e. won't have to cut out a square slot for a slide switch).

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Originally Posted by db Electronics

@AlecRob

Yes, once I'm satisfied with the audio quality and can come up with a software mechanism to enable/disable the FM chip I will start selling them. Stay tuned!!!

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I'm interested. count me in.

I thought the Genesis could do this already!?

I'm sure it *could* have, but it does not. Even the Japanese Power Base does not have FM sound.

Looks really interesting, I will keep an eye on it!

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Originally Posted by Da_Shocker

I thought the Genesis could do this already!?

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The Genesis uses a different FM chip than the Mark III does and they are not compatible.

I'm enjoying your Sega CD RAM cart, and have yet to get a SMS or PBC. Count me in as well.

This is really awesome - i was looking to get another power base converter going, and couldn't resolve how i'd go about tracking down an SMS & FM modding it, so i'm very interested in one of these! looking forward to seeing form factor, as well as Double Dragon stability (haha - for real, no idea why that one would crash on you). wish i could test Rampage! but yeah, please keep this thread updated.

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Originally Posted by IrishNinja

This is really awesome - i was looking to get another power base converter going, and couldn't resolve how i'd go about tracking down an SMS & FM modding it, so i'm very interested in one of these! looking forward to seeing form factor, as well as Double Dragon stability (haha - for real, no idea why that one would crash on you). wish i could test Rampage! but yeah, please keep this thread updated.

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I've already solved the Double Dragon stability issue. See the second video on the matter!

Form factor will be a simple Genesis cartridge shell with an SMS connector sticking out on top.

ah, didn't catch those - watching now! glad to hear it, and that FF works for me, any ideas for a label on it? we have a thread where members design em if anything! ill prolly keep my PBC around for segazord purposes but this sounds really great, saves me the shelf space of an SMS & another RGB cable too.

Great work on this from scratch. There will be buyers, heck Tototek sold tons of their MD flash carts because they had a Yamaha FM in it.

I managed to get the FM enable/disable working from the gamepad - no need for a switch on the board to do this.

The operation is extremely simple, if a game has FM sound, it will be enabled by default. But, if you wish to hear the PSG sound instead, you can hold UP during power up to disable the FM chip. Here's a video of the new feature:

http://youtu.be/vIP8IsxIvcY

nice! didn't know that'd be an option...the only thing i'd miss then is the ability to switch on the fly, is that not in the cards?

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Originally Posted by IrishNinja

nice! didn't know that'd be an option...the only thing i'd miss then is the ability to switch on the fly, is that not in the cards?

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I'm pretty sure it's impossible to switch on the fly. Master System games check for the FM chip only at startup and store the detection routine's result in RAM. There would be no way to make the system change that value during a game without heavy intrusion.

Count me in also...
It's still amazing to see new hardware getting developed.

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Originally Posted by db Electronics

I managed to get the FM enable/disable working from the gamepad - no need for a switch on the board to do this.

The operation is extremely simple, if a game has FM sound, it will be enabled by default. But, if you wish to hear the PSG sound instead, you can hold UP during power up to disable the FM chip. Here's a video of the new feature:

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Does any of your SMS converters work with Wonderboy III? . This game also has FM sound.

Does anyone know why the US version of Phantasy Star had the FM sound removed? Most other FM games just kept it in, I assume, because it was easier.

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Originally Posted by Segaedge

Does any of your SMS converters work with Wonderboy III? . This game also has FM sound.

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I know that Wonderboy In Monsterland won't work with a Genesis conrtroller, you must use an SMS controller for this one. I've never heard any complaints about Wonderboy III for my existing converter...

Awesome that it's controller switchable now. And no, you cannot switch on the fly. I have a US SMS modded with the FM board and a 3-way toggle (Japan/NA-FM/PSG), and switching with the game running does nothing.

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Originally Posted by Segaedge

Does any of your SMS converters work with Wonderboy III? . This game also has FM sound.

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It has a region combination lock out which keeps it from playing FM on various setups.

Make this Everdrive compatible and take my monies. This is awesome.

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Originally Posted by Kyle

Make this Everdrive compatible and take my monies. This is awesome.

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The Master Everdrive already works with my first PBC. There's really no reason why it wouldnt work with this new FM-PBC.

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Originally Posted by Black_Tiger

It has a region combination lock out which keeps it from playing FM on various setups.

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But if it's done right, the converter should be able to play Wondeboy III even without FM sound.

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Originally Posted by bishopcruz

Does anyone know why the US version of Phantasy Star had the FM sound removed? Most other FM games just kept it in, I assume, because it was easier.

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Yes, it was removed last I checked. If you want to play it in English with FM sound you need to use the English Retranslation ROM Hack. So you need either a Neo-Myth cart or a reproduction cart with the retranslated ROM.

Are you going to make a version compatible for Genesis flashcarts? In that way there could be some Genesis homebrew with the YM2413 and be able to play SMS games with the Genesis Everdrives. Best of both worlds!

ah, didn't know that's how it worked - okay, ill just have to be decisive about how i wanna hear a game then, heh. seriously, count me in for this.

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Originally Posted by TrekkiesUnite118

Yes, it was removed last I checked. If you want to play it in English with FM sound you need to use the English Retranslation ROM Hack. So you need either a Neo-Myth cart or a reproduction cart with the retranslated ROM.

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god i hate that, but yeah if i found a good repro with that translation i'd jump on it, next playthrough i do needs that sound.

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Originally Posted by villahed94

Are you going to make a version compatible for Genesis flashcarts? In that way there could be some Genesis homebrew with the YM2413 and be able to play SMS games with the Genesis Everdrives. Best of both worlds!

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a few posts above it was said that everdrives work

Just wanted to say I appreciate the work you've done on all these nice retro peripherals dbElec. Ram carts, HuCard convertors and now this!

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Originally Posted by db Electronics

The Master Everdrive already works with my first PBC. There's really no reason why it wouldnt work with this new FM-PBC.

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Ah, I didn't realize the PowerBase Mini was yours. Keep up the good work as they say!

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Originally Posted by Greg2600

Ah, I didn't realize the PowerBase Mini was yours. Keep up the good work as they say!

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Stone Age Gamer came up with the name "PowerBase Mini", I'm not used to calling it that so I keep saying PBC.

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Originally Posted by IrishNinja

a few posts above it was said that everdrives work

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Not the SMS Everdrive, I meant the Genesis ones such as the ED-MD and the Mega EverDrive.

right, i thought they were talking about those ones specifically, since this is a genesis peripheral?

Almost forgot to ask... is there a pause button on the unit?

crap...that's kind've important

Would it be possible to map the pause button to the Start button on the Genesis controller instead?

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Originally Posted by Joe Redifer

Almost forgot to ask... is there a pause button on the unit?

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Yes, there is a Pause button on the right near the top. Actually, if you go to my website www.db-elec.com you'll see pictures of my first PBC; the Pause button for the new FM PBC is exactly at the same spot.