Musical Memory Mapper vs. ordinary memory mapper cartridge -- any differences in performance?

Paladin (931)

05-12-2017, 10:41

Hey guys,

I've got a Panasonic FS-A1WX MSX2+ with the factory-standard 64kb RAM and 128kb VRAM, and I'm... not a hardware person in any way whatsoever (I've never soldered anything in my life, and am scared to try for fear of damaging my machine!), so I've mostly been using my system these last two and a half years to play cartridge games and Japanese disk games.

Recently, however, I saw a really good price for a "Musical Memory Mapper" cartridge on eBay, and while I don't really need the musical part of that cartridge for anything, I did find the memory mapper part a little too tempting (as it would increase my base RAM by 1024kb when inserted), and wound up buying the thing.

When I finally got it in the mail, I popped it in and tried it out with a variety of European games that typically require 128kb RAM instead of 64kb RAM... and, well, it works. But not with every game. I'd say the ratio is more like 50%, in fact.

Basically, here are the 128kb games I've tested it with, both successfully and unsuccessfully:

Successful (these work 100% flawlessly when I have the MMM cartridge inserted):
- Zoo
- Akin
- Core Dump demo
- Pumpkin Adventure III

Partially successful:
- The Witch's Revenge (it plays, but the intro graphics are pretty heavily corrupted)
- Ducktales (it mostly plays, but some options from the main menu cause my system to hang when selected)
- "Lilo" from KAI Magazine Collection cartridge (only if the game cartridge is in slot 1 and the MMM cartridge is in slot 2, for some reason; if it's the other way around, the game still hangs like it would if I tried playing it without the MMM cartridge inserted at all. Additionally, there's some graphic corruption in the intro when the screen attempts to scroll, but the game plays smoothly otherwise)

Unsuccessful:
- Pixess (claims I don't meet the 128kb RAM requirement, then hangs)
- Shrines of Enigma (displays the Sunrise logo, then hangs on a black screen)
- Sir Dan (hangs)
- Everything else from the KAI Magazine Collection cartridge (Nuts, No Name, and System Saver all run well but slowly without the MMM cartridge inserted, but they all exit to BASIC with a Syntax Error shortly after booting up if I have the MMM cartridge in)

Whew! OK. So I've been assuming the reason this doesn't work with 100% of the games I've tried is because some games just use different memory allocation code than others. But it occurred to me the other day that maaaaaybe the reason some of them don't work is because of the "Musical" part of this "Musical Memory Mapper" cartridge. Could it be, do you think, that whatever music-enhancement code is present on this cartridge is interfering with its ability to successfully allocate memory for certain games? Like, would I be better off with a simple 1024kb Memory Mapper cartridge, hold the "Musical"? Or should there, theoretically, be no difference whatsoever?

I figure someone here must know what the difference is between the Musical and non-Musical iterations of this cartridge, and must have some idea whether or not that difference could be cutting into my compatibility. Or perhaps someone here knows a way to get the most out of this cartridge, allowing me to play some of the games on my "unsuccessful" list, or have a better experience with some of the games from the "partially successful" list.

Really, any info anyone can provide at all would be appreciated!

Thanks, and take care!

-Tom

By gdx

Enlighted (5333)

05-12-2017, 11:15

wyrdwad wrote:

But it occurred to me the other day that maaaaaybe the reason some of them don't work is because of the "Musical" part of this "Musical Memory Mapper" cartridge. Could it be, do you think, that whatever music-enhancement code is present on this cartridge is interfering with its ability to successfully allocate memory for certain games?

No because the only difference with a standard Memory Mapper that can cause issue is the 3Fh I/O port. It is rarely used. I own a MMM. I do not know all the games you quote but I can try some on my MSX2 64k if you want. Are these all games on floppy disk or dsk image?

By Parn

Paladin (773)

05-12-2017, 13:13

Many European games and applications try to read the memory mapper registers, which is not allowed by the standard and causes a crash when there is more than one memory mapper in the system. They do this partially because European MSX2 machines usually already come with 128kB of memory mapper.

By gdx

Enlighted (5333)

05-12-2017, 14:32

Parn is right. There is probably a conflict with the internal Memory Mapper registers. Many European programs do not take this into account, emulators either. Best solution is certainly to make you the internal upgrade of 256kB.

http://www.msxarchive.nl/pub/msx/docs/hwmodsetc/msxa1wsxmemo...
https://www.ebay.com/itm/1PCS-M5M44256BP-10-DIP20-IC/2226265...
https://www.ebay.com/itm/Double-Row-2-54mm-20-Pin-DIP-IC-Soc...

By Juanmi

Master (134)

05-12-2017, 20:23

Hi wyrdwad,

Could you do a test for me? I have other FS-A1WX MSX2+ with 64kb RAM and 128kb VRAM, same like you (But with internal 220V transfo)
My Musical Memory Mapper doesn´t works with this model. Yes the 1024Kb RAM, but not the music when I launch the SG1000 program with .sg files.

I have others MSX models, and MMM works perfect, the only one with this problem it´s the A1WX.

Maybe the problem it's my computer, that's why I would appreciate it if you checked it for me.

Regards
Juanmi

By sd_snatcher

Prophet (3499)

05-12-2017, 22:14

IIRC, the Panasonic MSX2+ machines block readings to the external memory mapper registers.

User software shouldn't not only read the memory mapper registers, but also shouldn't do any direct I/O other than the VDP ports indicated by the BIOS. When the rules are not observed, incompatibilities like these arise. But oh well...

By Manuel

Ascended (18699)

05-12-2017, 23:35

gdx wrote:

There is probably a conflict with the internal Memory Mapper registers. Many European programs do not take this into account, emulators either

What exactly is not emulated?

By wyrdwad

Paladin (931)

06-12-2017, 04:51

Thanks for the replies, all! The takeaway, it seems, is that the music aspect of this cartridge shouldn't have any effect on the memory allocation, so even if I just bought a 1024kb memory mapper cartridge without the added music support, I'd still almost certainly have the same problem with these specific games -- am I correct on that?

I really should just bite the bullet and upgrade my internal RAM at some point -- but like I said, I'm scared of soldering and de-soldering and all that, so I'll probably wait until I've made a good friend with technical know-how and a soldering iron who owes me a favor.

gdx: I own most of the games I listed, save for Zoo, the Core Dump promo, Ducktales, and Sir Dan, all of which I downloaded as .dsk files. The problem is, the others are all games that you can't readily find online, some of which are still available for sale on various sites (like the KAI Magazine stuff), so I wouldn't feel comfortable sending you .dsk images. I appreciate the offer, though, and if you want to try out the ones that are available, that would be really helpful! Sir Dan is the only one that just plain wouldn't work at all, though, that you can find for download online pretty easily -- you'll find it as part of Future Disk #43.

Juanmi: To be honest, I bought the Musical Memory Mapper solely for the 1024kb RAM expansion, so I could play 128kb European games. I never intended to use the musical part of it, and I don't even know how to go about testing that -- I have no idea what program I'd need to download or install to try playing .sg files, nor where to even find .sg files. If you can direct me to where I need to go, though, and if it's something I can easily download and write to a floppy disk to test out, I'd be happy to give it a try for you!

-Tom

By gdx

Enlighted (5333)

06-12-2017, 08:38

Normally, only registers of internal Memory Mapper should have readable. Several Memory Mapper cartriges still have readable registers for MSXs that do not have an internal Memory Mapper. When a Memory Mapper cartridge with readable registers is insered in a slot of a MSX that already has an internal Memory Mapper, If the memory at the same size, it causes any problem. Otherwise, the most significant bits of the larger Memory Mapper will conflict with the unused bits of the smaller Memory Mapper. On some MSXs, the bits of the largest Memory Mapper take over and luckily it works. On the latest MSXs, developers have solved the problem by blocking the reading of external memory mapper registers. It's a shame that it's not the other way around.

Manuel wrote:

What exactly is not emulated?

The reading of external memory mapper registers is not blocked on emulated Panasonic MSX2+ and Turbo R. (I do not know which other real MSXs block it.)

Juanmi wrote:

My Musical Memory Mapper doesn´t works with this model. Yes the 1024Kb RAM, but not the music when I launch the SG1000 program with .sg files.

I have others MSX models, and MMM works perfect, the only one with this problem it´s the A1WX.

Have you notified the developer?

wyrdwad wrote:

J'apprécie l'offre, cependant, et si vous voulez essayer ceux qui sont disponibles, ce serait vraiment utile!

I tested Pixess and Shrines of Enigma on my FS-A1 MSX2, CF sunrise and the MMM with SofaRunIt, these work, but because the FS-A1 do not have internal Memory Mapper finally that would be not really helpful to you.

wyrdwad wrote:

I have no idea what program I'd need to download or install to try playing .sg files, nor where to even find .sg files.

You can find the loader in the wiki here. For SG-1000 Roms -> Google search. ;)

By Parn

Paladin (773)

06-12-2017, 19:55

wyrdwad wrote:

Hi, Tom. Unfortunately, you are correct. Certain games and apps, mostly European ones, were made in a way they'll only work correctly if you have only one memory mapper connected to your system (either an internal or external one), and it has 128kB or more. Programs should never read the memory mapper registers, but some do, as it tends to just work in the default configuration for MSX2 European users.

This doesn't mean your MMM is worthless. You can still use the musical part of it (you can try it by downloading a Master System soundtrack from SMS Power and playing it with Grauw's VGMPlay), and I believe the memory mapper itself will work fine with programs that use DOS2 mapper routines or implement their own support in a more behaved way.

By Popolon_fr

Resident (62)

06-12-2017, 20:49

Hi wyrdwad,

Quote:

Have you tested the hardware with diagnostic software? Does your MSX display 1088KB on your monitor screen after power up when the MMM is plugged into the slot? Can you test the memory with this TESTMAP.COM software? If nothing disturbs him, he will make a complete diagnosis of the memory.