Raiden II Mod - Debug, Stage Select, Region Change, Rapid Fire, etc.

[alamone]

I've released a mod for Raiden II. Includes the following features:

- Debug Mode Enable
- Stage Select
- Rapid Fire
- Region Switch
- Weapon Upgrade (+1 to weapon power even if you switch to different weapon)
- Sound Test

Stage select allows you to select:
- Stage
- Area
- Loop
- Miss counter
- Main weapon levels: Vulcan, Laser, Plasma
- Sub weapon levels: Nuclear, Homing
- Item stocks: Bombs, bomb type, fairy stock
- Extra option: Multi Weapon (allow all weapons to be used simultaneously)

Available on my github, pregenerated IPS and a build script from V30 sourcecode provided:
https://github.com/alamone/raiden2mod

Tested working on MAME and PCB (burn to 2x 27C240 EPROMs).

[TerminalInternet]

That's very interesting your programmer with the unofficial-mod support for the Raiden game series.

[emphatic]

Amazing work. Do you have a direct link to download all of your files, or does that only appear if you're logged into Github?

[alamone]

You should be able to click on the green "Code" dropdown menu and select "Download ZIP" to get it all at once.

[emphatic]

Thank you.

[Falkentyne]

Does your rom have a fix for the non-working difficulty dip switch selection?
I checked all the rom versions and due to some sort of bug in the hardware emulation, all of them are set to the "hard" difficulty, ignoring the dip setting completely.
"Easy" and "very hard" are exactly the same thing (all linked to "hard").

I was able to verify it with the arcade perfect windows 95 port that I still have, that has 4 difficulty settings that match the arcade (Captain, Major, Colonel, General), which actually work and make a rather large difference.
(I'm guessing Raiden 1, which uses the same base hardware, has the same issue).

I know this is an emulator bug, not the rom itself, as the arcade machines I played back in 1993 were never set this hard, so the port itself is arcade perfect (much like that pre-mame Callus emulator for Street Fighter 2 hyper fighting, that was written in assembly, having the correct gamespeed, etc).

[PC Engine Fan X!]

I was able to verify it with the arcade perfect windows 95 port that I still have, that has 4 difficulty settings that match the arcade (Captain, Major, Colonel, General), which actually work and make a rather large difference.
(I'm guessing Raiden 1, which uses the same base hardware, has the same issue).

The difficulty settings used in the Windows 95 port of Raiden II are based upon the very same difficulty settings of the earlier PSX/PSOne port of Seibu Kaihatsu's "The Raiden Project" game released back in 1995 with the very same names for each respective difficulty -- of course, CyberFront handled the development & subsequent release of the Win95 port of Raiden II (that's based on the PSX port of Raiden II).

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It's been said that there are slight differences between the PSX port of Raiden II compared to it's original arcade jamma pcb counterpart indeed and that they aren't the same.

At the very least, the Win95 port of Raiden II has all the BGM tunes presented in true 44.1kHz Redbook audio format (you can listen to them on an old-school music CD player) whereas with the PSX port of Raiden II, the BGM tunes are presented in the lower audio-spec grade "Yellowbook" audio format and playable/listenable with a "Goldfinger/Super Game Wizard" cheat device on the older PSX consoles with a parallel port located on the right-hand backside portion of the console itself.

On the PSOne, you'd have to use a "PS-X Change" cheat boot disc to listen to the PSX Raiden II's Yellowbook audio BGM tunes (as Sony did away with the parallel port entirely).
----------

PC Engine Fan X! ^_~

[alamone]

Does your rom have a fix for the non-working difficulty dip switch selection?
I checked all the rom versions and due to some sort of bug in the hardware emulation, all of them are set to the "hard" difficulty, ignoring the dip setting completely.
"Easy" and "very hard" are exactly the same thing (all linked to "hard").

I was able to verify it with the arcade perfect windows 95 port that I still have, that has 4 difficulty settings that match the arcade (Captain, Major, Colonel, General), which actually work and make a rather large difference.
(I'm guessing Raiden 1, which uses the same base hardware, has the same issue).

I know this is an emulator bug, not the rom itself, as the arcade machines I played back in 1993 were never set this hard, so the port itself is arcade perfect (much like that pre-mame Callus emulator for Street Fighter 2 hyper fighting, that was written in assembly, having the correct gamespeed, etc).

Hi Falkentyne, thanks for the reply. I'm performing analysis on the ROM, but it appears to be actually baked into the ROM code itself, not an emulator bug. The difficulty tables that are set via the DIP switches are almost identical, except for the "Hard" setting which is marginally harder. Regarding your claim that the real arcade PCB has a lower difficulty, this is probably because you happened to play one of the "easier" ROM sets, because there are multiple ROM sets with more substantial difficulty tuning. The one my patch is applied to is the Japanese (normal, not harder) set, which may be tuned harder than the particular set you played in the arcade.

[rtw]

SEIBU did not make it easy for us with their many different versions.

Back in the day I dumped: Raiden 2, Seibu License, Easy Version

According to DragonKnight Zero's excellent Raiden 2 FAQ this PCB is the easy version.

The different versions may be identified by the high score screen. The easy version has the Raiden MK-II in colour on a black background whereas the hard version has a sepia shot of an ascending fighter.

The entire FAQ is available here:

http://www.gamefaqs.com/coinop/arcade/game/10729.html

Checksums were:

r2_prg_0.bin 524288 0x2abc848c 27C240
r2_prg_1.bin 524288 0x509ade43 27C240
r2_fx0.bin 131072 0xc709bdf6 27C1024
r2_snd.bin 65536 0x6bad0a3e 27C512
r2_voi1.bin 262144 0x488d050f 27C020
r2_voi2.bin 262144 0x8cf0d17e TC534000P

[PC Engine Fan X!]

For rtw,

Fascinating to learn that the sepia colored Raiden II pcb that Fabtek released in the USA is the harder and more difficult version -- it certainly earned it's chops as a true "quarter muncher" back in February of 1994 with it's American debut indeed.

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What was noteworthy about a typical Seibu Kaihatsu Raiden II pcb is, if it had a back-up battery on-board, it'd save both high scores and high score initials as well (as mentioned in the instruction manual itself). However, once the on-board backup battery died, then saving of such high scores & high score initials were lost for good. So back in 1994-1995, I'd see such Fabtek Raiden II conversion kits hosted in the full-sized Dynamo upright cabs complete with the latest high scores & high score initials intact even if they were powered down for the night, they'd appear unchanged from the night before.
----------

PC Engine Fan X! ^_~

[rtw]

The saving of Raiden II hi-scores is an interesting story.

There was an investigation here:

https://www.arcade-projects.com/threads ... save.6787/

Schematics show that only one custom is powered by the battery.

It looks like code cannot be executed from the custom but maybe it could store a magic value which is checked by the cpu ?

If the magic value is set maybe the initial hi-score table is not initialised ?

Now that we have better reversing tools maybe we can finally get to the bottom of this ?

[PC Engine Fan X!]

On the Fabtek Raiden II pcbs with a backup battery, all Top 10 High Scores + High Score initials would be saved (and not just the Top 3 either).

PC Engine Fan X! ^_~

[alamone]

Raiden II / DX high-score saving — RE findings

Hi, I don't want to discount PC Engine Fan X's testimony, but everything I've seen from RE analysis points to high score saving being an urban legend.
PC Engine Fan X, can you confirm that you actually saw the cabinet being powered down for the evening at the arcade you went to? It might have just been left on 24/7.

TL/DR: I reverse-engineered the high-score path in Raiden II and Raiden DX and tested rtw's "magic value in the custom" idea directly. Across every ROM revision I could run, the main CPU performs zero reads from the battery-backed custom at boot. That means it's impossible for the main CPU to be checking any "magic word" read from the battery backed custom. There is also no save/restore code in any of them.

More details:
What the code does (both games, confirmed by disassembly + live MAME tracing):
- At every power-on the boot routine unconditionally zero-fills all work RAM, then builds the high-score table from hardcoded ROM defaults (R2: a compute loop; DX: copied from per-course ROM tables, initials hardcoded to "***"). It reads no saved data. The display/name-entry code only ever touches that volatile work-RAM table. Nothing writes saved scores into it — I tapped every write to the table region and only the wipe and the default-builder ever fire.

Testing rtw's hypothesis (could the SEI252 hold a magic value the CPU checks?):
- This was the right place to look, and it's the one thing MAME-side traces miss, because MAME doesn't map the SEI252's interface — so any CPU access to it shows up as *unmapped*. I logged unmapped accesses across a full boot. Result: 92 unmapped writes (COP microcode / sprite setup), zero unmapped reads. The CPU programs the customs but never reads a value back from them. I also traced the COP (SEI1000) itself — it only does the per-frame sprite DMA and standard math macros; it never touches the score region or reads the SEI252.

The variant sweep (the interesting part):
- Since the difficulty tiers are genuinely different builds, I ran the same unmapped-read test on ~20 sets: raiden2j, raiden2 (US Fabtek — turns out it's 2 bytes from raiden2j, both a region tag), raiden2u, the *easier* family (raiden2e/eu/ea/eua/eub/es/i/nl/sw — including the different-RAM-layout builds), the *harder* (raiden2k, raiden2dx), the 4-ROM prototype (raiden2eup), and Raiden DX in every region I have. All of them: 0 custom reads. (raiden2g/hk were the only outliers — both fail romset verification and crash, and they're single-ROM region clones of raiden2 anyway.)

On the battery: it powers only the SEI252 (matches twistedsymphony's trace; I confirmed it on my own board — work RAM runs on plain +5V, not backed). That's the sprite-key suicide cell, and it's redundant on Raiden 2/DX because the keys are reprogrammed from ROM every boot — which is why boards run perfectly with it dead or removed.

The one thing software analysis can't settle: the SEI252's internal SRAM is a battery-backed, undocumented black box that MAME doesn't emulate. I can't see inside it. But it's a sprite-decryption chip with no path to the score RAM, and no revision ever reads it for that purpose — so every piece of evidence we *can* inspect says the feature doesn't exist.

Credit to twistedsymphony's earlier teardown on arcade-projects for the battery trace and the first look at the default-table builder — this lines up with and extends it.

[rtw]

Thank you for your detailed and thorough analysis @alamone!

[PC Engine Fan X!]

Here's the original Japanese manual for Raiden II jamma pcb: https://files.stardustarcade.com/PDF_Ar ... en%202.pdf

The last page, I think, mentions something about high score saving. Could we have one of our Japanese reading/speaking shmuppers translate the very last page of it please?

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Here's the English/German Raiden II manual mentions that something about the battery (which is quite vague as it is): https://www.arcade-museum.com/manuals-v ... den-II.pdf


Back in 1995 at the Circus-Circus casino arcade in Reno - NV, they had a Dynamo upright cab with Raiden II up & running (and even the Capcom CPS1 Varth stg as well). It had a Top High Score list with high score initials. Here's the clinker, the Dynamo cab had a specialized pcb setup that would be powered 24/7 that would save high scores and high score initials upon being powered down for the night and upon being rebooted up and the high scores would be still be intact -- this would apply to any jamma pcb regardless if it had a backup battery in place, on-board NVRAM or not. Was a sure fire way to shorten an arcade pcb's lifespan if ran for 24/7 all day everyday in an arcade environment type with no access to a proper surge protector back in the early-to-mid 1990s era. Of course, it was all up to the arcade owner/operator chuck the current arcade pcb if it wasn't earning it's upkeep and replace it with the newest arcade pcb to earn it's "street-cred" either "out on location" or in an indy arcade type of establishment.


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There was a Dynamo upright cab running Amecian Technos jamma pcb of BlockOut that would save both high scores and high score initials and would appear intact the next even if the cab was turned off. When I finally got a BlockOut jamma pcb, I thought that I could save both high scores and high score initials directly to the pcb itself through NVRAM or other means -- I was mistaken as upon being powered down and rebooted again, it showed the default high scores and high score initials. So I had to deduce that those Dynamo upright cabs had some kind of specialized pcb circuity to run the jamma pcbs 24/7 in order to retain such high scores and high initials period.
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So back in the early to mid-1990s, those Dynamo upright cabs had some kind of specialized pcb circuity hooked to the arcade PSU that still had the installed jamma pcb powered up 24/7 even if the actual cab was turned off (meaning the arcade monitor and upper-front backlit arcade marquee were turned off completely) -- so it would still have all the high scores and high score initials intact from the previous night before. That is the only conclusion that be concluded based on my own "trial and error" experiment as with the BlockOut jamma pcb itself as proof of evidence that it doesn't save high scores period. Mystery is finally solved with the Raiden II and BlockOut jamma pcbs don't save high scores nor high score initials indeed.

The Atari Games' Klax jamma pcb is an oddball one in that it does save both high scores, high score initials & player histograms through NVRAM even if the pcb is turned off -- this was all achieved back in February of 1990 with it's intial release in arcades worldwide. It was prominently shown at Marriot's Great America amusmement park in Santa Clara, CA back in April of 1990 which was the first time I had seen it up & running (of course, Atari Games HQ was based out of Milpitas, CA which was a "hop and skip" away from Santa Clara anyways in Silicon Valley/Bay Area).

PC Engine Fan X! ^_~

[alamone]

Last page says nothing about saving high scores. I can read Japanese.

Point 3 says that the portions of the circuit are battery backed, to avoid shorts do not probe for continuity. Also, do not remove the battery.
It says nothing about saving high scores, just generically that "some parts of the circuit" are battery backed.
Of course, we know that it's the sprite encryption keys that are battery backed, but it's a moot point because the ROM restores them on boot regardless.

注意事項
1. PCボードの取り付け、取り外しは必ず電源を切ってから行って下さい。
2. 本ボードに張ってあるシリアルナンバーシールを剥がした場合や、無断で改造
した場合には、故障に際して保障期間内であっても有償又は対象外となります。
3. 回路は一部バッテリーバックアップされており、テスターなどで導通検査などを
するとショートの原因になりますので絶対に御止め下さい。また絶対にバッテリー
は外さないで下さい。
4. PCボードを輸送する際には、スポンジやエアキャップなどで包み、段ボール箱
などに入れ強い衝撃を加えないようご注意下さい。

Again, I'm asking you, did you personally witness the cabinet being completely powered off? Otherwise, again, I have to conclude it was simply running 24/7.

[PC Engine Fan X!]

Yes, the power to all the arcade cabs were turned off including the Fabtek Raiden II cab by 10:30pm - 11:00pm. When the power was restored the next morning by 7:30am - 8:00am, the Raiden II cab still had it's current Top 10 Scores & high score initials intact from the previous night -- so that told me that the Raiden II Dynamo cab had specialized circuity to keep the Raiden II jamma pcb running 24/7 (even though the arcade monitor & marquee were turned off completely for the night).

Even the Dynamo cab running Varth had it's current high scores & high score initials intact as well.

PC Engine Fan X! ^_~

[alamone]

Thank you for the clarification PC Engine Fan X. Given that Varth also does not save high scores (it has no NVRAM that could do this), I think we can conclude that it's simply the PCBs being powered on 24/7 in the cabinet, rather than the PCBs saving high scores when turned off. The board was assumed to be powered down along with the (visibly dark) monitor and marquee, but was in fact still energized — which is why a non-saving board like Varth "kept" its scores too. An urban legend born from that misunderstanding.