2 Player SNAC Adapters on the MiSTer FPGA (NES, SNES, and PSX) 

Yeah, it had crossed my mind while I was responding to your other comment, that my multi-player might interest you :)

Hmmm... can you please share a little more information about your setup? What 2P SNACs are you using, and what do you have J17 and SW7 set to?

@@whatskenmaking i use the multisystem with jumper to IO and 5V. I have older dual SNAC adapters from ultimatemister with the level shifter between.

@@retromister81 Thanks for the additional info... I'll have to take a look at the ultimatemister version of the adapter; I'm guessing there's a difference from the open source adapter that I was using.

Good question, I actually don’t know if it will work or not. Some other multitap devices do work fine, but the NES isn’t listed on the misteraddons store. I’ll have to see if I can dig one up and test it.

Thanks! I just have a cheap set from Amazon - www.amazon.com/gp/product/B07PJSS18N. They work fine but, I tend to use my microscope for board inspection more often than the eye loupe.

Thank you! The SNAC port directly connects your controller's pins into the Cyclone's GPIO pins. The GPIO pins are exposed via the headers on the DE10-Nano, so you technically don't need an I/O board for SNAC. If you'd like, you can wire up your own USB3 port directly to the GPIOs. However, there are some nuances that you need to consider, such as the state of 7th SNAC pin. The I/O board has a jumper built in (IO6) that enables you to configure that. Regarding mixed SNAC/USB - that's a great question... and it depends on the core. For example, the PSX core allows you to configure input for both players independently, but the NES core has a single setting for both players. Would love to see your console case design!

He covered why it was needed in his previous video about SNAC. The User IO port is 3.3v and the controllers supported by SNAC are pretty much all 5v (raw arcade controls notwithstanding). If we ever get N64 SNAC we’ll finally have a 3.3v console that wouldn’t need the voltage level conversion. Some SNAC stuff has the level conversion built-in but the original official MiSTer designs do not. I feel that the level shifter should probably be a cable since you definitely don’t need a rigid protrusion like that with a controller or two hanging off it.

Interesting. I’ve been using a SNES SNAC board (which is literally just straight usb pins to SNES pins) with no level shifter and it’s worked just fine. Should I modify my setup to use a shifter?

@@emmettturner9452 thanks for the thorough reply.

@@Mike-B-Jackson What I/O board do you have? Some have the level shifters built in (MINI, PLUS, Multisystem, etc). The level shifter seems like an afterthought that was added after someone balked about the proper way to handle 5v devices on a 3.3v bus, so I suspect it will generally work fine without. This is just my speculation since I wasn’t even aware of it until recently. Like 3.3v flash carts inside of 5v consoles, I suspect it generally works but can be bad for the chips… theoretically. SNES controllers are basically just two 4021 shift registers in series which is off the shelf logic… so it’s no big deal if we burn one out. Since we are undervolting it, chances are it won’t hurt anything in the controller, so maybe it’s to avoid putting too much strain on the FPGA.

@@TheMikeyb86 No problem. I had just finished that video hours before this one went live so it was fresh on my mind. :)

Depends on what you want SNAC for. Low latency isn’t the only reason for SNAC. Using more obscure hardware from the original console, like light guns, multi taps, spinners, and specialty controllers (Super Game Boy controller, anyone?) is also a good reason. Personally, I went with the Decapod DB9 for the best of both worlds. It works as a multiplatform SNAC adapter for several consoles when used with Antonio Villena’s “DB9” SNAC IO boards and also works as a Daemonbite adapter when used with a USB cable. There’s even a Daemonbite-only version for a little less. I’m still getting set up but the only thing I found lacking is PSX support. He also sells an “Octopod” with PSX controller support but it doesn’t have the sync connection for GunCon. It’s also way too expensive and mostly redundant if you already have the Decapod. He does offer a cheap DB9 PlayStation adapter with the sync jack so I’ll be adding that to my Decapod to make up for it.

@@emmettturner9452 Interesting stuff!! I was actually looking at Antonio's mister. But I decided to go for the standard for now. The Deca- and Octopod's looks great, if you have the Antonio DB9 port. But they also have some limits. Like you can only use two controllers of the same type at once. I guess it depends on your use case.

I've seen the Daemonbite adapters, but have not tried them myself. Low latency USB adapters are great, but even at 1ms, there's still a 6.25% chance of your input missing a frame. SNAC avoids that entirely by not using polling at all. I explain how this works in my first video on SNACs; you might be interested in checking that out if you haven't seen it - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-tRrNN2HXuVQ.html. By the way, there is one USB option that I'm exploring a bit more and will be doing a video on soon - the BlisSTer. Even though it's a USB device, it has a layer they call the Low-Level API (LLAPI), which frame locks the polling in the core. I'm running some experiments with it to see if it really can get us zero latency USB😁

@@whatskenmaking Sounds good!! I have already seen the video, but I was just thinking a millisecond delay would be fine. Anyway, I'm looking forward to the blisster video!! Thank you!!

@@whatskenmaking not true at all. Every singles console have its internal pooling aswell, generally once a frame, aka 60 hz. No console reads inputs instantaneosly like the way you are implying lol. The chance of a pooling done @1000hz miss the window of the core logic pooling @ 60hz inst even close to 6.25%

I haven't tried it personally - but according to the SNAX documentation, yes it will work.

Interesting...I haven't tried the snax64 yet, but it sounds like it may require a different configuration

I have not tested it myself, but the documentation says that it only works with a single PC Engine/TG-16 controller.

Technically, yes - but I don't believe the SNAX has been open-sourced.

It depends on the system, but the SNES, Genesis, Saturn, and PSX multitaps are all reported to work with the SNAX. I have an NES multitap, but I have not yet tested it. I'll be doing a follow-up video soon with some additional SNAC adapters, and am planning on covering some multitap support as part of that.

But then I wouldn't have anything fun to troubleshoot 😁 The problems I was having weren't due to the SNAC adapters - it was because of the MiSTer Multisystem; all the two-player SNACs worked fine on the traditional MiSTer stack configuration. I do like Antonio's devices - they're very nice!

I use Antonio’s DB9 Octopod. It’s great but it has the same issue with the PCE/TG16 multitap.

Ha - I'm going to win one of these days... maybe 😆

😂 I rather like to think of Richard Leadbetter as the British Ken 🤣🤣