Super Game Module technical forum

[Super Game Module technical forum]

Thanks!

AY-3-8910 datasheet states it needs 1-2MHz for a clock, so dividing the cpu clock is the easiest way.

The MSX runs the PSG at 1.7897725 MHz, which is half the cpu clock ( 3.579545MHz, same as the CV ), so of course he'd do it that way.

Also, adding an extra crystal just increases board size and cost, when the expansion port has a clock line already... Sometimes I think too hard about things and miss the obvious. :facepalm:

 

If you're doing a port from MSX to Colecovision, the SN76489 can use same values as AY-3-8910, just make sure you don't exceed 10 bits (AY-3-8910 has 12 bits of frequency)

I ran into that a few months back and posted a question in another thread here. However, when the MSX uses all 12 bits, that's when the fun starts...

[Super Game Module technical forum]

I've probably missed this somewhere, but after numerous searches I can't find it, so I figured I'd ask here.

Does the SGM use the CV system clock ( 3.579545MHz ) divided by 2 for the AY-3-8910, or is there a separate crystal (4MHz/2 = 2MHz ?) ?

Still working on an MSX-CV conversion, and (I think?) it makes a difference in the note frequency.

[MSX -> CV sound conversion]

I know this is a little off-topic, but I didn't know if this warranted it's own thread.

 

I emailed the company and this is what I get:

 

Hello, this is HAL Laboratory, Inc.

 

Thank you for your email.

 

We considered your offer to port the MSX version of

Eggerland Mystery to Colecovision, but a conclusion has

been reached to not accept your offer as our company.

 

We apologize that we couldn’t come up with your expected

answers, but we'd like to ask you to understand our decision.

 

Sincerely yours,

HAL Laboratory, Inc.

http://www.hallab.co.jp/

[email protected]

 

I'm not completely sure they understood what I was asking, since all I asked for was an email address, someone I could contact for permission to do a port. I know as a company they wouldn't want to publish anything themselves, since they wouldn't make anything from the few copies they'd sell. I'll probably reply and ask for clarification, but I'm not really sure what to ask. Anyone else done this before? Any tips? I hate to give up now, but they did make the original game, and I don't want to cause any trouble.

[MSX -> CV sound conversion]

If you can make it fit in 32K, you could also use my Activision PCB, which supports an auxiliary savegame EEPROM. The EEPROM I/O works in test situations, but I have yet to release a game that uses it. The first game to do so will probably be The Black Onyx next year.

 

But it's all theoretical talk now, since you don't intend to put the game on carts.

 

Sorry, I knew I should have phrased that differently, I have trouble putting thoughts into words sometimes.. I'd like to eventually release in cart form, just need to figure out who to talk to about it, and what permissions I'd need to get for it. I just meant there weren't any immediate plans for it, since I haven't talked to anyone about it yet. I certainly didn't want to state release dates, then end up running into copyright issues or something.

If all else fails I'll probably just release the ROM, or a ROM patch, and let people do whatever with it.

 

Do you have a datasheet or some tech info for your PCB somewhere, just to see if I could make that work? I'm guessing it uses either an I/O port or a small section of memory, or maybe swaps it in and out, like a megacart?

[MSX -> CV sound conversion]

Opcode Games highly recommends including some SGM detection routines to be used at boot time. Eduardo can probably supply you with what you need.

Yeah, I'll have to read through the SGM technical thread(s?) again and see what I can find, but I'll message him as well and see what happens.

 

There's no emulator that supports the SGM in its final incarnation.

 

Well, then I'll probably end up adding whatever info I can find to the random mess of an emulator I wrote ~10 years ago, which is also what I've (mostly) been using for debugging. There's no sound support atm, since I'm terrible at sound programming, which is mostly why I started this thread in the first place. Again, I'll have to look over specs/talk to Eduardo for the info.

 

Really? I don't recall that. Must have been a long time ago... Or perhaps it was on someone else's to-do list. Anyway, I never had any plans to publish Eggerland Mystery on the ColecoVision. But I am 100% sure I will buy a copy if it eventually gets released on cartridge!

 

I thought I remembered it mentioned somewhere.. maybe in a poll to see what people were interested in seeing ported next? Eh, doesn't matter.

Also, no plans atm for any specific release, either ROM or cart.. I need to figure out who and what to ask about it; I definitely don't want to get sued by someone for copyright or any other issues. >.<

 

Also, adding the replacements for the MSX BIOS routines may make your game go over the 32K limit. It wouldn't surprise me, since Eggerland Mystery has over 100 levels, so the original MSX game must run up very close to the 32K line. You may need to resort to using an Opcode MegaCart, but if you do, you'll have a minimum of 128K to work with, which means you could theoretically add a bunch of new levels not found in the original MSX game. This would be easy too: Just import all the levels from the three NES Lolo games, with some slight modifications. Or you could run a contest for people to submit new levels!

 

Actually, the MSX Eggerland ROM has some rather large areas used only for disk access, saving and loading levels, and various other features in the mini level editor that aren't needed on the CV. (editor still works, btw, just can't save anything permanently, but what would you save to anyway? I suppose there are data packs/disks on the ADAM, but, I doubt I want to go there. Feature creep is an evil thing.) I have 200+ bytes free even after converting the graphics and other random BIOS routines necessary to run, which should be more than enough to add the sound BIOS routines and also any initialization/SGM test routines needed. That said, the level and graphics data takes up about 12-15k, though it's not always easy to tell what's what in the data sections, there are some compression routines that I'm not completely sure about yet. That's also why it uses so much RAM, it unpacks the levels into RAM a few at a time.

 

Using a MegaCart is an interesting idea, though that's a huge amount of space. Even if the compression is terrible, that's still room for over 500 more levels, and more likely 2-3 times that.

 

So many things to think about.. And here I thought I was almost done with the port.

[MSX -> CV sound conversion]

So many replies already!

I've used a trick in Princess Quest,...

...You program the channel 3 (noise) for fixed envelope and variable frequency (uses channel 2 that you should mute) and you put in channel 2 frequency the original data value divided by 15...

 

Ah, that's a cool trick! I knew you could set up the noise channel that way, but I didn't realize you could do that with the frequency. I'll have to play around with that sometime, either with this or some future project.

 

The number of people that would play this on an ADAM are probably pretty small compared to the number that would play on a ColecoVision. Seeing as the game will require the SGM to work anyway, you should just go ahead and make it a SGM required game...

 

Alright, I figured that, but I thought I'd ask anyway. Even if I use the SGM for sound, it should still work on an ADAM without the SGM, just with no sound.

 

What NIAD said.

 

The sound chip inside the SGM is an MSX sound chip. It is used by such games as the MSX ports of King's Valley and Thexder (and will likely be used by other upcoming MSX ports such as Goonies and Knightmare) so the SGM is required to play those games on the Adam as well as the CV.

 

Yeah, the SGM having the same chip as the MSX means it's very simple to port, just change the output port number, and add a couple small routines to replace the MSX BIOS sound routines.

Now to find an emulator with SGM support, if they exist yet... Maybe it's time to add sound emulation to mine.

 

Oh, and :thumbsup: for porting Eggerland Mystery, I loved Adventures of Lolo on NES.

 

Me too! Also, my apologies if I've intruded on your plans.. I think I remember seeing Eggerland Mystery on at least one of your lists of future ports.

[MSX -> CV sound conversion]

Hello all!

I've recently been working on a port of Eggerland Mystery from MSX to CV, and have it mostly finished. However, I've run into a problem with the sound conversion and wanted to get some opinions. Basically, the MSX sound chip has a larger range than the SN76489 the CV uses, so a direct note-to-note conversion means about half the bass notes are missing. I know there are a few options, but I thought I'd see what you guys thought.

 

1. Leave the sound as-is, and have it run only with the super game module. Since it currently uses about 16K RAM, it will only run on an ADAM or with the SGM anyway. Are there really that many people that would want to use this on an ADAM, and not have a SGM?

 

2. Do some kind of editing to the music: either remove the bass channel, or raise the whole channel an octave.

 

3. Rewrite the music completely, change it to something else, maybe from another version of Eggerland/Lolo.

 

4. Something else????

 

Anyone else doing ports had this issue? What did you do?