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BubbleDrive8 - a multiloader for Konami's bubble games

ikamusume

ikamusume

Student
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Seoul, Korea
BBD8.jpg


My two-year project is coming to an end. It is a multi loader for Konami's bubble game that can emulate eight ROM images. Bubble memory's protocol itself is easy, but the production was delayed because I was programming diagnostics for the board. The resources are open, but it needs to be cleaned up. I'm still working on it.

I've made this item for me and my friend, so I don't have any plan to receive an order. However, there is a possibility of selling it if there's a little number of remainders after making a small batch.

I'm trying to contribute to MiSTer FPGA by developing a bubble PCB core for MiSTer. I've completed its video board. Now I'm focusing on drawing its schematics and implementing its bubble memory controller. The bubble controller is a YAMAHA gate array manufactured under 1.5um process and was used as a sequencer instead of MC6801 MCU which was originally used by Fujitsu. We can't use a firmware file because it's a gate array, not just an MCU. Nevertheless, I think I'll be able to provide some information for improving the emulation of MAME.

Thank you for reading this post.
 
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Incredible.

It's always been a quiet little pipe dream grail of mine to plunk down the cash for a real gradius, but the bubble system hardware being so notoriously fragile never gives me any warm-fuzzies about committing to the buy. Really great to hear your moving your efforts over to Mister- another ungodly expensive and scarce set of games made more accessible to the masses is always a great thing to see.

Thank you for your work!
 
“Prototype v3.1” That’s a lot of work. Congrats!!
 
Fantastic stuff. If I had a bubble system I’d be all over this. I’m keen to see your core for MiSTer… more fantastic additions!
 
Nice worrk! I'll never own the original ($$$$) hardware, looking forward to the MAME implementation.
 
Thank you for the update. And thank you for all the research and hard work that you have put into this as well. Is your project the same or unrelated to the project shown by the Beep Shop in Tokyo? (and the “bubble-less” project)?

I have a long standing question that I have been unable to get an answer for. So we know that there were 5 bubble system games. (Twin Bee, Gradius, Road Fighter 2, Hyper Crash, Galactic Warriors) And we also know that Gradius (Nemesis), Road Fighter 2 (Konami GT), and Hyper Crash (Attack Rush) were also released on regular solid state PCB’s. So, my question is, isn’t it technologically possible to get Twin Bee and Galactic Warriors to run on standard PCB’s? Using a standard GX400 bottom board, and some other Konami top board as the donor? Neither Twin Bee nor Galactic Warriors require special controls and neither is very large in rom size. So surely this must be possible and certainly I can’t be the only one who is curious?
 
Supergun said:
Thank you for the update. And thank you for all the research and hard work that you have put into this as well. Is your project the same or unrelated to the project shown by the Beep Shop in Tokyo? (and the “bubble-less” project)?

I have a long standing question that I have been unable to get an answer for. So we know that there were 5 bubble system games. (Twin Bee, Gradius, Road Fighter 2, Hyper Crash, Galactic Warriors) And we also know that Gradius (Nemesis), Road Fighter 2 (Konami GT), and Hyper Crash (Attack Rush) were also released on regular solid state PCB’s. So, my question is, isn’t it technologically possible to get Twin Bee and Galactic Warriors to run on standard PCB’s? Using a standard GX400 bottom board, and some other Konami top board as the donor? Neither Twin Bee nor Galactic Warriors require special controls and neither is very large in rom size. So surely this must be possible and certainly I can’t be the only one who is curious?
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1. It's not related to the project you mentioned, but I was inspired by it.

2. There are four games released on the bubble platform. They are TwinBee, Gradius, RF2, and Galactic Warriors, and are all 2 megabit versions. Attack Rush is mistakenly known to have been released on that system because it was on the flyer. However, it has not been released. At least, as far as I know, no one of my Japanese acquaintances have seen it.

3. The comments on MAME source are wrong. The board used by TwinBee and GW is exactly the same as the other one. This is the same for both ROM and bubble releases. It's possible to swap ROM images to change the game.
 
Excellent.
Thank you so much for replying.

And thank you for clarifying about Hyper Crash (Attack Rush) I understand that part now. I too was confused and misled by Konami’s advertisement flyer.

So then to be clear, it is indeed possible to play TwinBee and Galactic Warriors on a Nemesis/Konami GT board by simply programming the correct EPROMs and placing them in the correct positions.

When I had first looked into this a few years back, since the games were so much smaller and didn’t match up perfectly as they do with Nemesis and Konami GT, I just assumed they were not compatible or playable on that board. But if I have this right now, they actually are, but the rom data might need to be “padded” or “doubled up” etc. in order to fill the proper size eprom for the corresponding location on the board.
 
Supergun said:
Excellent.
Thank you so much for replying.

And thank you for clarifying about Hyper Crash (Attack Rush) I understand that part now. I too was confused and misled by Konami’s advertisement flyer.

So then to be clear, it is indeed possible to play TwinBee and Galactic Warriors on a Nemesis/Konami GT board by simply programming the correct EPROMs and placing them in the correct positions.

When I had first looked into this a few years back, since the games were so much smaller and didn’t match up perfectly as they do with Nemesis and Konami GT, I just assumed they were not compatible or playable on that board. But if I have this right now, they actually are, but the rom data might need to be “padded” or “doubled up” etc. in order to fill the proper size eprom for the corresponding location on the board.
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Did you mean loading the bubble version or the revised ROM image on a Nemesis/RF2 board? Straightforwardly, it's impossible.

I can't write much about hardware and program here. The first bubble versions run game program after loading the bootloader and some system routines used by 68000. They use TRAP exceptions to read bubble memory. The later EPROM versions are missing 4kB code that was present in the bubble version. I didn't take a closer look at what that was. And, a PCB for the EPROM version has a bootloader ROM to replace a bubble memory controller. Some TRAP routines used by the bubble version use the bubble memory controller, but the bootloader ROM of the EPROM version has different TRAP routines that can allow programs to treat a game ROM as a previous bubble memory.

In addition, the bubble hardware has a VLM5030 voice synthesizer and sends the sound program to Z80 RAM using DMA. 68000 checks the BIOS data on the Z80 side.
 
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I’m still confused then.
September of 2019 you said:

“…I correctly dumped Bubble System TwinBee. Has been checked on a real machine…”

By “real machine” did you not mean the standard rom board such as those used by Konami GT and Nemesis?

And yes, I understand that the bubble system is configured differently and that it loads and runs the program code differently. Etc. But again, my question is why can’t the Twin Bee and Galactic Warriors rom data be “modified/changed/split/merged/patched/hacked” etc. (whatever it takes) so that it can run on the Konami GT/Nemesis board set? Again, clearly it was done with those 2 games. And all 4 games originally ran on the same bubble system. So how is it “impossible” if it was already done with 2 of the 4 games?
 
The phrase including "real machine" I mentioned is not a Nemesis/Konami GT board. It's a bubble system PCB.


Here's a table of hardware differences between 3 PCBs

Bubble SystemRevised ROM version of Bubble SystemNemesis Konami GT
72 scanline counter(necessary hardware)OOX
bubble memory controllerOX (has a bootloader that emulates it)X
VLM5030 voice synthesizerOOX
Z80 watchdogOOX (uses an external watchdog chip)
Bubble System "BIOS"OOX

First of all, we need an external scanline counter that sends an interrupt request to the 68000 to measure the time. Otherwise, we can't listen to morning music. I don't know how to implement this in software. The Z80 monitors the 68000 using a register of an AY-3-8910, provides bubble BIOS to the 68000, and acts as a watchdog. The Z80 performs important tasks. It opens its eyes before the 68000 runs.

The way the bubble software runs is also different. Bubble games run the game after copying only the necessary parts to RAM. On the contrary, Nemesis/Konami GT allows the CPU to access all parts of the game program from the beginning. This suggests that there is a difference in the management engine. Even worse, apart from the considerable amount of RAM shortage, the RAM address is different. The RAM of the Nemesis/Konami GT PCB should be expanded, and the expanded RAM should be mapped appropriately to the software.

We also need to modify Z80 sound driver. The entire sound program of the bubble game is loaded to RAM while playing morning music, which means a parameter or data can be changed during runtime. Nemesis/Konami GT has a ROM for the driver that can't be modified in real-time.


Since Konami had the original source, it would have been easy to modify. All they have to do is modify the management engine that controls the flow of the game, change a few constants, and assemble them. However, we don't have the original source. A challenger would have to build a patch program that can change significant amounts of differences and make games run avoiding hardware constraints.
 
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If you don't plan to reproduce it. Perhaps consider open sourcing it or outsourcing production to somebody else?
 
Great work!, I would also like to purchase if you have any remainders.
 
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