MiSTer FPGA Forum

I have a Neo Geo 4 slot cabinet and was pondering if emulation of the multi slot system could be done. For those not aware, a real Neo Geo cabinet can have a 1/2/4/6 slot motherboard, usually with a matching marquee with exchangeable light-up mini marquees to tell you which game you're currently viewing/playing. When in attract mode, one can press the change game button to move to the next one. Once a game is actually started you can't switch it.

The main limiting factor of course would be the SDRAM. If a second 128MB card were added (as was proposed for the PS1 core at one point), 256MB still wouldn't let you load the 4 biggest games (about 88.5MB each I think). But there are plenty of combinations that would fit into even into a 128MB bank.

I guess my question is: is there anything beyond RAM limits that would prevent the core from acting just like a 2/4/6 slot?

Thanks

What's the point?

jca wrote: ↑Fri Dec 31, 2021 1:19 amWhat's the point?

The point is to replicate original hardware. Press the next game button and it switches to the cart in the next slot. MAME can load up multiple slots.

It’d probably be able to be done in a pseudo-emulated form where only one game actually needs to be loaded, but it mimics the functionality close enough? I really don’t know much about the way it works on OG hardware in this case.

Yeah probably needs some interaction with the HPS side.

On an MVS, it seems that pins 26/d of the "JAMMA"-like connector are used for the game selection buttons (same ones used for button 5 on CHAMMA).

I would in fact love if more signals like these were allowed to be mapped in/out of the system. Coin counters, status LEDs etc are common to see in arcade games.

This could probably done on other cores as well. I remember my Dentist office when I was a kid had a Sega Genesis kiosk that had a multiple cart switcher and a button that would reset the system and switch to the next game. Would love to have everything set up just like that and use the user button or the core reset button on the MiSTer to cycle between them.

I'm guessing something similar could be achieved with Super Attract Mode script.

https://github.com/mrchrisster/MiSTer_SAM

keilmillerjr wrote: ↑Fri Dec 31, 2021 4:49 am

jca wrote: ↑Fri Dec 31, 2021 1:19 amWhat's the point?

The point is to replicate original hardware. Press the next game button and it switches to the cart in the next slot. MAME can load up multiple slots.

Plus those machines also had rotating attract mode between the games and a marquee that would light up when said game was on display or being played. NEOGEO cabs were the most detailed cabs at the time in my opinion.. not only did they have multigame with marquee lighting up each game when selected, they also had LED credit counters for each player, individual headphone jacks in the cabinet per player and also memory card slots per player.

callanabrown wrote: ↑Fri Dec 31, 2021 12:55 am I have a Neo Geo 4 slot cabinet and was pondering if emulation of the multi slot system could be done. For those not aware, a real Neo Geo cabinet can have a 1/2/4/6 slot motherboard, usually with a matching marquee with exchangeable light-up mini marquees to tell you which game you're currently viewing/playing. When in attract mode, one can press the change game button to move to the next one. Once a game is actually started you can't switch it.

The main limiting factor of course would be the SDRAM. If a second 128MB card were added (as was proposed for the PS1 core at one point), 256MB still wouldn't let you load the 4 biggest games (about 88.5MB each I think). But there are plenty of combinations that would fit into even into a 128MB bank.

I guess my question is: is there anything beyond RAM limits that would prevent the core from acting just like a 2/4/6 slot?

Thanks

I am pretty sure there is a ram limit there. The MiSTer at the moment still needs to load Rom files, and depending on their size takes time.|
Neo Geo Roms are HUGE compared to other consoles, so ignoring the ram restrictions you just be dealing with the load times every time you switch games.

redsteakraw wrote: ↑Fri Jan 14, 2022 4:02 pm This could probably done on other cores as well. I remember my Dentist office when I was a kid had a Sega Genesis kiosk that had a multiple cart switcher and a button that would reset the system and switch to the next game. Would love to have everything set up just like that and use the user button or the core reset button on the MiSTer to cycle between them.

The game swapping was done externally to the Genesis console, it was ether done via transistor logic or a custom ASIC.
A Similar thing was done with the Nintendo M82 which was a In-store Kiosk for the NES/Famicom. It used a custom ASIC with a timer that forces a reboot after a preset amount of time.

CaptainWolf wrote: ↑Thu Feb 03, 2022 12:17 pm I'm guessing something similar could be achieved with Super Attract Mode script.

https://github.com/mrchrisster/MiSTer_SAM

I am sure the current Attract Mode Script can simulate the 2/4/6 slot experience, just limit your roms to a few Neo Geo Roms.

I don't know maybe we can have a playlist which will cycle through games in a list. It can be generalized between cores use the keyboard media controls or a next game button.

Registered to say I'd love to see this.
MAME emulates the slots, marquee and 7-segment LED outputs (which can be read in windows / linux).
I have a windows machine in my custom cab, but it would be great to swap in a mister.

https://youtube.com/shorts/1pEM0gVvqpg?feature=share
https://www.youtube.com/watch?v=lp00N5eoVbo

There isn't really any way to do this realistically on the NeoGeo core. There isn't enough SDRAM to load more than one ROM if one of them is the largest ROM. Additionally, the way the indexing for the loading of the roms into SDRAM works, it has to be something repeatable to do this, so if the roms are different sizes, I don't think it would work at all. It doesn't seem worth it to do since you can already switch games in about 2-3 seconds if you want, by just loading a ROM file again. And the MVS switching feature didn't change anything with respect to gameplay of any of the games.

Just because MAME does something doesn't mean it's plausible or even possible on MiSTer. MAME is a software emulator and can do lots of very complicated tasks using high-level emulation and a powerful CPU and large amounts of RAM. MiSTer doesn't have the same capabilities to do a lot of these special things.

Summary: Almost zero benefit for a ton of work and might not even be possible.

just smack multiple MiSTer boards into a cab, wire them up to a hdmi switch and hook the swap button to the channel switcher and there you go!

costly and impractical to boot!

I finally got myself a (australian) big red 6 slot machine. It's currently got a 4 slot neogeo board in it, but this thread got me thinking...

• MiSTer with Jammix set to MVS
• Super attract mode script, modify it so pressing the change game button will make SAM script change to next random neogeo game

Stretch goals

• Replace backlit LED marquee on machine with a LCD or OLED display, have it replicate the look of the old marquee
• run a script on the MiSTer to change the display to display info on the current game (either replicate the look of the original marquee or have additional info come up on how to play, moves list etc)

It's going to still have that brief mister rom loading screen, but it's pretty fast anway