Making Sense of SNACs on the MiSTer FPGA
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- เผยแพร่เมื่อ 22 มิ.ย. 2023
- Continuing on with my look into the MiSTer FPGA gaming project, I'm diving into SNAC adapters and how they help replicate the feel of original game systems. In this video, I explain a bit about how SNACs overcome some of the challenges with USB device frame accuracy, show off a couple of SNACs in action, and repair a faulty SNAC adapter that I purchased online.
Links mentioned in this video:
- SNAC Adapter GitHub Repo - github.com/blue212/SNAC-adapters
- SNAC Level Shifter (USB Plug) - misterfpga.co.uk/product/mist...
- SNAC Level Shifter (HDMI Plug) - misterfpga.co.uk/product/mist...
- SNAX - misteraddons.com/products/ser...
- SNAC Adapters (HDMI Plug) - misteraddons.com/collections/...
- SNAC Adapters (USB Plug) - misterfpga.co.uk/product/mist...
- Ultimate SNACs - ultimatemister.com/product-ca... - เกม
You have a way of explaining things that makes it easy to understand for someone that is new to a topic, now I have a high level understanding of how input polling works.
Another good and clear video. Now I get what snac adapters to get and why. Thanks!!!
This video on the SNAC adapters instantly made me think of these Raphnet adapters I have been collecting over the years. I believe not enough people know about input polling/latency, and how it can actually affect your gameplay, or even your memories of said gameplay. It's a niche topic, but there is a lot of information to absorb out there.
For anyone wanting these direct controller access communication methods, but on your PC (without a mister), there are adapters called raphnet adapters. Raphnet has adapters for pretty much every retro console, and all the USB adapters are low level communication/direct access (no lag/similar to playing on real hardware/console). They also have some neat adapters for actual consoles, things like a NES adapter, letting you use a wired SNES controller on a NES, among various of combinations.
Edit: Wanted to add that I believe any of those raphnet USB adapters should work on any device that accepts USB input, it does not require any dedicated software. However, you can get software on PC, to monitor/change the controller polling, and other various settings, optionally. Default will be the lowest input latency akin to real hardware.
Not really comparable to snac. Raphnet adapters have at least 3 or 4 ms lag. Snac is 0 lag.
@@zlk718even if you use raphnet's softwares/apps to lower the adapters' latency?
@@zlk718 0 added lag, not 0 lag, as some games have lag built in their input handling routines. Each game polls controllers slightly differently, some do at the end of a frame or on the blanking interval, some do at the start of the frame and will only affect the next frame, which results in a perceived ~15ms (max, or 7~8ms avg) lag on NTSC.
@@ultraspinalki11 look up "mister fpga input latency", there's a huge list of controllers and adapters that have been tested with a special setup involving a modified MiSTer core and an Arduino. Raphnet adapters seem to be pretty decent with
Here are btw my testing with the Multisystem:
Master System: 5V or 3.3V - only IO6
Mega Drive 3 Button: 5V or 3.3V - only IO6
Mega Drive 6 Button: 5V or 3.3V - only IO6
NES: 5V - only IO6
SNES: 5V or 3.3V - IO6 or IOMister
PCE: 5V or 3.3V - IO6 or IOMister
PSX: 3.3V - IO6
Excellent and informative video! Love that you show the many types of SNACs, as it could get very confusing with the different models and variations!
I'm also somewhat relieved that others are having trouble with the same model NES SNAC. Mine feels mismapped and some buttons don't register at all. (Up is Start, B is A, and it's on auto direction Right.) I don't have the right know how, so I gave up on it, but it's great that you gave some insight as to why it may not be working. Thank you so much for this video!
Thank you! I would definitely check the connections on the NES controller port ... the NES SNAC is just a straight pin remapping, so there isn't a whole lot that can go wrong with it. I'm willing to bet that you just need to replace that connector like I did. The mismapped buttons could be happening because the clock or serial data line is getting garbled due to a bad connection.
@@whatskenmaking Thanks, Ken! Perhaps I'll use this as springboard to start a new hobby. :)
You got a new sub! Such a nice and easy to understand video. I look forward to your other videos on the MiSTer!
Loving your videos! Thanks for taking time to explain everything! Appreciate it!
Great video! Subscribed and I’m looking forward to see what other MiSTer content you come up with.
You earned yourself another subscriber. Great video! Thank you.
I'm new to Mister , so just doing my research, thanks for this video.. New sub.
You think you're some kind of tough guy, playing Contra without the 30 life cheat code? 😂 Great video!
😂
Awesome video!
wow! really interesting video regarding emulations...
vary helpful video thanks.
Hello friend, to play with the SNAC on the Atari2600 with the paddles, do you have to power it with 5v?
Great vid. I would have liked to see the NES zapper, but that would require a CRT, so I understand why you didn't include it.
It works, you just need either a CRT with RGB / YPbPr input or an adapter to get Composite or S-Video out of the MiSTer. I've tested with a couple of active adapters and it worked flawlessly. One of them use a AD724 chip to convert RGBHV to Composite and S-Video, there are options for either NTSC or PAL-B/G/D/K/I/L color carriers, or both, witch a selector switch. There's also an active adapter that's just a bunch of filters and an video op amp, the video carrier is generated in the MiSTer itself and you select the carrier frequency on MiSTer.ini.
This might be a little of a headache if you're switching between 50Hz and 60Hz games depending on what weirdness your TV expect. I've seen TVs that accept both, but has to use it's native color carrier no matter the framerate, while others give a rolling image unless the signal has a color carrier matching what you'd expect for such a framerate, others might be more tolerant and just accept pretty much any nonsensical combination you throw at it. Once you figure out what works for your TV, just save it on a couple of alternative ini files and switch as needed.
Really interesting video, I'm looking at getting some SNAC adapters and didn't realise a level shifter was required for my digital IO board. I think I'll pick some up soon and try them with my Super Famicom controllers, and in the mean time I'll see if the fast polling works on my USB controllers 🙂
Yeah, that was confusing for me, too, when I first started looking at SNACs last year. Reliable information was hard to find, so I wanted to put the results of my own experiences out there for others. Good luck!
Realise I am a bit late here but for original controllers do you have to worry about region lock? as in would original JP SNES controllers work on snac as well as PAL ones for instance? im still a bit lost here tbh but im getting more and more interested in mister stuff since sadly some of my older systems have become damaged.
No, there are generally no regional lock issues with controllers. Region lock in the older consoles was typically implemented via a dedicated lockout chip inside the console. The controllers were all the same (for the most part… there actually is a minor difference on PAL NES controllers, but that’s an anomaly). I’ve used controllers from different regions (including JP SNES controllers) with SNAC without any issues.
@@whatskenmaking Thanks for the reply. I did not know that the controllers were all the same I thought they also had lock out chips. Ill pick up some JP controllers for SNES next time I am out there.
Wow that was really great, I never bothered with SNAC because the info’s all over the place. Now I’m interested. Do you have any knowledge of dual PS1 multitaps running on Mister? My favorite thing in the world was 8 player micro machines, I’d love to experience that one more time in my life.
I am hypersensitive to input lag. I can't stand it. Anything above 4 or 5 ms messes with me. I'm so stoked that there are options like this.
I haven't used my NES SNAC yet, so I wonder if I'll have the same issue as you did. At least I'll know how to fix it. Also worth mentioning that the Playstation SNAC should be used without the level shifter. I don't have a Multisystem, but I assume you'd push the switch next to the user port to the right (5V).
Good point - I have a PSX SNAC on order but haven’t tried it out myself yet.
Not bought any snack adaptors yet, it's a great option to have to use original controlers.
IMHO, the original controller is only slightly more important than a good CRT if you want the original feel of these games. The original hardware is great, but the parts other than the controller don't add as much to the experience.
i fear wearing out the snac port by changing adapters for different systems, anyway to use it with a hub?
Not an off the shelf USB hub, no - those hubs use USB controller chips and the SNAC is serial data. You could theoretically make a switch that remaps the pins between multiple USB connectors, but it would be more like an old school physical device switch. I think USB ports are pretty resilient, though - I have several old devices with USB ports that I've used quite a bit which are still going strong. Still, if it's something you're concerned about, you can look into one of the multi-SNAC adapters, such as this one - ultimatemister.com/product/ultimate-snac-multi6/
@@whatskenmaking that things awesome ken thanks for the tip, hope it comes back in stock soon.... maybe I am worrying for nothing but I have memories of usb ports loosening and coming off of my PC back in the early 2000's, since then I've been OCD about the things lol
@@cwells7285 If the larger metal housing posts on the usb connector are soldered in place (which I believe they are - I don’t have an IO board in front of me to check right now) then I think it’s less likely the solder joints on the port will break. You could always re-solder the connector back on if it does happen, though 😁
I have the Atari SNAC adapter and trying to get paddles working. Joystick working fine. I have plugged in the 3.5mm cable and selected paddles on hardware switch. . I seem to have a different version of the core than you. My update script removed the Atari 2600 core so I have been using Atari 7800 core to run 2600 games. Unfortunately it doesn’t have the option to select “Paddle ADC = Yes” which may be what I’m missing.
The normal Atari 2600 core was superseded by the 7800 core because the 7800 will also play 2600 games (the 7800 is backwards compatible with the 2600). But for analog input via SNAC, you’re going to have to grab an unofficial Atari 2600 core from here - drive.google.com/drive/folders/16kwYrD81m-18XJLfqVSNag7Rj-eGpCBS. That’s the one I used in the video. Just copy the RBF file into the folder with the rest of your cores. Good luck!
@@whatskenmakingYour tip was perfect! I guess I get confused when some of the cores have menu options that allude to SNAC plus analog support but it hasn’t been implemented yet.
I’m also interested in getting original lightguns working in Mister. Tried for ages to get Sega Justifier working a few months ago. If you ever do a SNAC follow up video I’d be keen to see lightguns as well as the BlisSTer board covered. BlisSTer has onboard HDMI style zero lag ports.
Sorry to bother you, but is the Atari adapter compatible with a Genesis controller? I think it should be, but want to be sure.
Awesome explanation - I subbed, - but I have the MISTer from antoniovillena which comes with a DB9 port instead of a HDMI or USB - I also got the decapod - but - and I am not sure how this works but there is a option in the console cores to enable user-io and its normally different to the SNAC option, - and it allows me to use my new Big-6 controller with all the consoles I tried so far - which is pretty amazing, since the MegaDrive was my console of choice. - So I haven't even tried plugging in other controllers. I noticed the new MD-core doesnt have this option, I cant remember if I got forked cores, - need to figure it out, but I hardly hear anyone talk about it.
Thanks! I've had some other folks mention the DB9 port variant as well as the decapod, but I haven't had a chance to try them out yet. I believe what's happening under the hood is that an HPS bridge is established to integrate the serial controllers that are plugged into the FPGA GPIO pins into the Linux OS running on the HPS side of the Cyclone as a Linux userio module. This effectively lets the serial controller be used in as a universal I/O device in Linux... and this is why you can get menu control in the MiSTer OSD with it. The thing I'm not sure about is what kind of latency its subject to... it's going through the Linux kernel running the HPS before the I/O data gets fed back into the FPGA, so I assume there's some latency aspect there, even if it's not as high as a USB host controller. Regardless, it's an enticing option to never have to plug in a USB controller :)
@@whatskenmaking - I still have to keep a keyboard because it doesnt work with any arcade core menu, and it doesnt work with any console until its enabled per-console. The keyboard is also just quicker in many cases. - but being able to use the Big-6 to play all sorts of consoles - thats pretty amazing. Technically - I have no idea, but I would be keep to hear if there is some lag. - because accoriding to Antonio its ZERO. - I dont think there is lag because it works with light guns and from what I understand - lightguns dont work if there is any lag at all.
This is was my main problem with modern keyboards, even my IBM reproduction model F... they're almost all USB, while the input difference between polling and interrupt is nigh impossible to actually notice it can actually be quite different depending on what's going on and interrupt has very specific use cases where it may be necessary. That being said the only other interface standard besides USB that's still made for keyboards is PS/2 and that standard might as well be dead.
Agreed, USB has its advantages, but there’s something to be said for non-polling input devices and the benefits they bring as well.
Changing the adapter for each system seems kinda annoying. Especially when you also want to use the mt32-pi for MIDI. Would be nice if there were multiple ports.
There actually are a couple of SNACs that folks have created with multiple ports - one that I know about (but never tried) is the multi-SNAC that the folks at ultimatemister.com make. I don't think it will help with the MT32-Pi situation, though.
I'm surprised they don't have something to load into the FPGA on boot to present it as a USB HID device so the SNAC controllers can control the menu system too.
It would be possible to configure an HPS-to-FPGA bridge, which would essentially allow the HPS to delegate logic to the FPGA, but I do think it would require a bit of work. You’d need to emulate the serial I/O interfaces for controllers of the various systems in the FPGA, and you’d need to write a Linux driver to present it to the OS as an HID device. I wouldn’t be surprised if someone, somewhere was working on one though!
There is SNAC8 (DB9 user port), which already supports controlling the Mister's menu, 2 simultaneous players, and more. It's not available for official IO nor Multisystem, only for the Ironclad Plus and Villena's boards.
Not much about DB9 but this is the best SNAC video. Thanks!
I don’t understand that SNAX chart at 8:30. If SNAC and SNAX truly support a single native PCE/TG16 port then they should also support 2-5P via multitap, since the consoles only ever had one port. Judging by the chart’s explicit consideration for multitaps and the actual number of players enabled by SNAC vs. SNAX, it would be really weird if that were just an oversight where they left something out.
If it is somehow incompatible then it isn’t really behaving much like a native port, which would defeat the purpose somewhat and presumably cause issues with 6-button pads too. Some 2-button controllers even have the multitap built in, like my Micomsoft XE-1 HE Pro.
I’m also confused about dual-controller PSX via SNAX. Shouldn’t it support 8P with two multi taps exactly like an original console? If not, is it a power issue?
Anyway, it’s not entirely true that you can’t navigate the main MiSTer menu with SNAC inputs. I’m using DB9 MiSTer fork in Update_All and I can navigate the MiSTer menus with a Genesis pad whether I’m using my DB9 SNAC adapter (DB9 Decapod w/MT32pi) or not. Supposedly it also works with DE15 (Neo-Geo/arcade sticks) but I haven’t tried those with my Decapod yet. I presume this branch was made for MiSTer JAMMA kits or replica microcomputer cases that only have DB9 ports (C64, Amiga, etc).
The Decapod specifically doesn’t let you navigate the main MiSTer menu with NES/SNES/PCE/TG16 controllers but I don’t see why it wouldn’t be similarly possible.
Now I’m confused about the best way to get dual PSX + GunCon support for my DB9 setup. Antonio Villena sells a “Octopod” with dual PSX ports but there is no sync connection for GunCon. Also, the other ports are all covered by the Decapod making it extremely redundant (Octo=8; Deca=10)… and it isn’t cheap.
Questions I still have:
What about DE15 for PC Gameport and Famicom EXT? Some PC games used all four analog potentiometers whether for 2P (Y-cable) or joystick + rudders. Famicom EXT is used for all sorts of specialty adapters and controllers. So far it seems DE15 is exclusively for arcade controls… or at least those are the only examples I can find. I’d love to connect an old Sidewinder Force Feedback racing wheel with a PC core, which may actually work since it is digital, much like MIDI.
Thank you! I haven't used any of the DE-9 (sometimes referred to as DB-9, though DE-9 is technically the correct name for the connector) SNAC adapters, but I'll add it to the list of things to check out. I'm planning on doing a deep dive on the TG16 support in the near future, and the TurboTap is on my radar of things to explore. I do have the boards to make a buffered and non-buffered TG16 adapter, and the fact that a buffer chip is needed to get the turbo support working correctly makes want to understand a bit more why. In theory, unless an analog signal is needed, the SNACs should only need to be passive boards.
Regarding PSX SNAX - I agree, and would expect that 8P with two multitaps would probably work. I actually have a SNAX video coming out in the next few hours, where I took a look at the SNAX board a little more closely. Does the PSX multi-tap support rumble? There's a current booster built into the SNAX for rumble support, so if the multi-tap can support rumble, there might be current draw limitations. I don't have any experience with PSX multi-taps, so I'm just shooting from the hip on that one as a possible concern. Regarding PSX GunCon support - the SNAX has a sync connector for GunCon, but I haven't tried it yet. I have been using dual PSX controllers with my SNAX and it works great.
Thanks for pointing out the info on the menu navigation support - it's something I'll look into. I knew it would be possible to wire up an HPS bridge for menu control, but there would need to be explicit support for specific controllers and a Linux driver to go along with it. Sounds like maybe that's the case with the fork you're using, since you're saying it only works with the Genesis (and possibly the NeoGeo) controller. The reason for this is because you'd either have to emulate clock/latch/data lines for each type of controller in the HPS, or you'd have to load a light-weight FPGA config middleware to simulate just the I/O chips of the system in question and do a serial transfer over to the HPS with a driver to interpret it. This would require writing controller-specific verilog/C code. In fact, it makes a lot of sense that they would use a Genesis controller because it's one of the simplest types of controllers to grab I/O from - it has a separate pin that's polled for each switch, except for the switches that run through its multiplexer... you could easily write a driver for it. If that's the case, then it should also work with an Atari controller. If you feel like giving it a try with one, I'd be really curious to know if it works. :)
The Decapod is something that I haven't looked into yet, but it looks really interesting, so I'll take a look!
Regarding a PC game port - I haven't done much research there, but there are two issues that can see right off the bat. First, there's only 9 pins available on the SNAC port, so if more than 9 pins on the DA-15 port are used, then they can't be connected via SNAC. But the second issue is support for 4 analog inputs. FPGAs use digital logic, so you'd need to put the analog connection through the MiSTer's ADC, and there's only one of those.
On the Famicom - there actually is a 15-pin Famicom expansion SNAC, and I do have some of those PCBs, but have not made one yet. I noticed that several of the pins on the DA-15 connector aren't routed to anything, so I assume it's only connecting the pins necessary for 3rd party Famicom controller support. I need to find the time to solder one up and play with it.
Thanks so much for the great information - you've given me a few more things to do some research on, and a couple more ideas for future MiSTer videos :)
@@whatskenmaking Yes, even the Update_All MiSTer fork refers to it incorrectly as DB9. “DB9” really refers more to Antonio’s SNAC8/ENCC implementation. After forcing myself to say “DB9” I believe I referred to the 15 pin Neo Geo and Famicom EXT port as “DE15” when they are actually DA15. ;) Unfortunately, I have to keep saying “DB9” since that’s their official name for this form of SNAC and they even distinguish product variations that way (there is a “DB9 version” of the Decapod and another that only works as a USB DaemonBite adapter).
Regarding the buffered vs. unbuffered PCE/TG16 support: I guess that answers that! Sounds like a confirmed incompatibility with unbuffered adapters. I’ll have to see if the DB9 Decapod is affected. You may recall that Old Skool released a TG16 controller that didn’t work with the multitap because they populated the board with the wrong resistors and left out bypass capacitors (I had to point this out for them to fix it), so perhaps this is similar.
I believe the original PSX multitap design predates DualShock controllers but I expect force feedback generally works. It’s possible that 8 controllers vibrating all at once might be a little too much but perhaps Sony addressed that on the software side (official programming standards for licensing which forbid developers from doing that with 8 players?).
I searched Antonio’s store again and I see he does sell a dual PSX port DB9 splitter with the GunCon sync jack, so I’ll end up ordering that. It says it has a jack for providing external 9v. Meanwhile, the DB9 Octopod said it generates 9v internally. I’ll pass since there is no GunCon sync, it supports fewer controllers than the DB9 Decapod I already have, and of those few most are already supported by the DB9 Decapod. Oh: …and it’s not cheap! I could only justify splurging on the DB9 Decapod.
Yes, because the USB-style user port was replaced with a DE9 connector the “DB9” MiSTer fork supports such controllers for menu navigation without an adapter. All the other adapters/splitters plug into that same DE9 port and work as SNAC, including a dual DE9 splitter and USB3-style adapter for existing SNAC devices. I tested with an Atari CX-40 but the single button defaults to Menu making it impossible to make any selections. I didn’t look to see if I could remap it to make selections.
If your I/O board has JAMMA, DA15, or DE9 the so-called DB9 cores also support arcade/DE9 controllers without a bespoke adapter, regardless of whether or not those controls are native to the specific core. This means you can use a Genesis pad in all the cores and still get the advantage of SNAC in Genesis/MegaCD/32X cores. Supposedly it’s still potentially lower latency than USB for the non-native cores, so however they are doing it no longer relies on the USB polling rate.
Regarding the Decapod: If you do look into it, keep in mind that there are two versions. Both support Daemonbite USB but only the “DB9” one also works like a multi-platform SNAC adapter.
It would’ve been really cool to see multiple ADCs for analog flight sticks… or even Atari Warlords or whatever that 4P paddle game was called. Oh well. Maybe the TheRasteri’s WeeCee is a better option for PC Gameport stuff.
I assume the FC EXT SNAC connector is wired for controllers like the NES/SNES SNAC and may not support all the weird and wonderful stuff they have in Japan, like the Data Recorder, Battle Box, and more. HijiQuish Channel is in Japanese but I highly recommend seeing the obscure Famicom EXT hardware that guy like to show off. I’ll just have to accept that we can’t bring every little thing to the MiSTer!
Guess I need to dig out my CX-78 Joypad or Pro-Line sticks to see if it can register the extra button and if that makes MiSTer DB9 navigable with an Atari controller. I already tried a TAC-2 but both buttons function the same (Fire 1).
You've really piqued my interest with the "DB9" 😉 decapod - I'll need to place and order and spend some time with it. It sounds interesting enough to warrant it's own video. I have an arcade machine in the works, but wasn't planning on doing JAMMA, since I'll be using a modern VGA display inside of it.
I love the idea of the WeeCee... not sure I'm ready to play with one just yet, though. Definitely agree about the usefulness of more analog inputs!
I'll definitely check out the obscure FC hardware! I do have an FC and FDS in my collection (which I composite modded a couple of years ago), but it mostly sits on display. I could use some accessories to encourage me to bring it off the shelf and spend some time with it!
Ken says he owns physical copy of wonderboy but even if he didn’t, there is no scenario where authorities will ever investigate which physical copies he owns and which ones match the roms he possesses. The only way ken can get in trouble is If he sells roms or hardware with roms on it and the authorities wouldn’t care whether he owned the physical copies of games or not. I just wanted to pop in and say that and also say have fun with roms
😁 I just said that because it’s not a super common game to have and I just added it to my collection a couple of months ago when I got a good deal on it at Midwest Gaming Classic. But I hear what you’re saying!
love your channel. mister is great but sometimes (like paddles) makes me want to keep the original hardware...do you think mister replace OH?
danger will robinson