Pi2Jamma

[noonan2678]

Anyone else get one of these from Arcade Forge (Jochen)?

I've got mine sort of working, but with many issues.

1. Vid output is VERY dull
2. Aspect ratio on some games is way off
3. Can't access settings of any kind outside of getting into the specific game board settings
4. A "dynamic resolution" patch is made available, but no clue how to apply/manipulate it.

There is a bit of a language barrier, but I am still surprised at the lack of understanding from
someone who was able to design a board like this. He's missed basic stuff so far that I've
figured out on my own.

He supplies what seems to be a custom (maybe not?) front end and an image that doesn't seem
to give any access to the traditional PiFBA or MAME programs. There are errors upon bootup, etc.
PiFBA, for instance, has options to enable aspect ratio correction, but I can't seem to access anything.

Thanks, Guys.

[Fudoh]

Can you test the Pi2Jamma adapter with a standard Retropie or Recalbox installation ? Bob (retrorgb) recently posted a really easy tutorial on youtube. I have no idea why you would want to use any software beside these.

[noonan2678]

I could try that, yes. I was thinking that Jochen used what he used on purpose to be compatible with the Pi2Jamma build.
I agree that there are better emulators than what he is currently using. The output just looks like crap and is def not the
correct machine aspect ratio on many games.

Bob had Jochen on one of his last roundups too. Hate to say, but not a lot of help.

Also - no idea where to put buttons 4-6 on the jamma harness. Since most people would have kick harnesses, some wiring
would be necessary to send the extra buttons to the harness.

EDIT - check out 38:05. Believe he's saying that it is proprietary.

https://www.youtube.com/watch?v=ZUZFolmwma0&t=1571s

[Fudoh]

yes, he's talking about the controller mapping. That's to be expected. But to get an idea about video quality, signal resolution and aspect ratio, I don't think that he's using any other GPIO pins than the Gert666 adapter does. So, just for the sake of testing, give it a try - just attach a USB controller for the time being.

[noonan2678]

Ok, will do as soon as I can. Is there a build I should be looking for or just a couple of app installs? 1st time with a Pi.

[Fudoh]

Get the standard Retropie or Recalbox SD card image and follow the instructions on the RetroRGB video (was posted something like 2 weeks ago).

[RGB0b]

I haven't personally tried, but the Pi2Jamma should be compatible with all software available, however it's proprietary software is only compatible with it's hardware. You should be able to follow this guide / video for it to work: http://www.retrorgb.com/rpi240pvga.html

Also, I've recently discovered Lakka which is a pretty cool interface that looks decent in 240p and the config.txt file can be edited right on the SD card (it's kept in the FAT32 partition) - This will allow easy tweaking of the video modes: http://www.lakka.tv/get/linux/rpi2/

If you're able to test, let us know how it worked out for you.

[noonan2678]

Thanks, Guys! I'll test as soon as I can and post back here.

[jugu]

Any updates?

I ordered one myself, Pi2Jamma, but it won't be here for another couple of weeks. Wondering if things are better with the latest images or with different Pi releases.

[Dochartaigh]

The problem on all of these with the Raspberry Pi 3 is how the Pi is completely and utterly setup from the hardware to the [default] programming for HDMI output. I'm dealing with the Pi2SCART - but the basics for pi2Jamma is near identical in terms of display resolution.

The biggest hurdle seems to be the Pi 3's pixel clock (that's a big part of how you fine-tune all the settings to get the correct H sync and V sync in essence so it displays properly on your CRT monitor). There's only maybe 6?-ish pixel clock settings allowed on the Pi 3 so when you're fine-tuning your CRT TV's display you're stuck with one of those - and the pixel clock setting anywhere around 240p is pretty crappy for 240p content (which is like ALL/most of the arcade stuff, NES, SNES, Genesis, etc. etc. etc.). My CRT video output for example is a good 12-15% larger than any one of my 240p consoles - which probably isn't a problem if you're fine-tuning this for one single arcade cabinet, but for people like me it's a problem because I spent HOURS and hours setting up my BVM/PVM's so they look decent (not perfect) on any one of my 6 consoles and I'm not about to get into the service menus (or even adjusting physical pots INSIDE certain PVM's) to fine-tune my monitor for the Pi 3, then adjust it back again every single time I want to switch back and forth to/from the Pi 3 to/from my consoles - just not possible.

One workaround people just started using is a HUGE 1600x240 pixel size (regular is 320x240) with likewise huge front/back porch settings. This fools the system into using those limited pixel clock settings, while still displaying content correctly despite the limited amount of pixel clock settings, and the ability to properly scale and center the image. (totally in-theory as I still have to try this myself to see if it works as well as they say it does but it may fix some of the setup issues mentioned here).

Besides all that, the other half of these common problems is the RetroArch settings which are mainly setup for HDMI output which absolutely rapes the image quality on a CRT monitor. Most of the emulation software images people use will have RetroArch at the core (or the ones I've tested at least do - I'm a tried and true RetroPie man myself after trying several others). Basically you have to turn off all the HDMI-specific settings, turn off all the filtering and upscaling stuff, to get it to display a nice clean RGB signal. I originally thought the image quality was absolutely horrible until I started to tweak these settings. I used this article as my base (I like the pixel perfect setting - especially for arcade) and I can switch back and forth from my consoles to the Pi 3, on the same game on the same level, and it's like ~90% identical (the ~10% difference is how the emulator is different than the actual console hardware - which is pretty minute to be honest - looks GREAT).

[bobrocks95]

Is actual rendering changed to 240p? So then the filtering is being performed on a 320x240 image? Doesn't sound like that would look good at all.

[Dochartaigh]

Is actual rendering changed to 240p? So then the filtering is being performed on a 320x240 image? Doesn't sound like that would look good at all.

The normal way of getting the Pi2SCART or the Pi2Jamma boards to work is a regular 320x240 (240p) hdmi_timings setting you put in the Pi's /boot/config.txt file. This is the default setting ArcadeForge recommends you use. It makes the Pi output a true 240p image which is what people want for these CRT monitors since the native games run at that resolution. BUT the filtering I'm talking about is then being performed on that 240p signal by RetroArch, which you're right in saying it doesn't look good at all. That's why if you follow the settings in the article I linked to it turns off all those settings and you then get a true unfettered, un-messed-with 240p image which closely mimics the RGB signal from a video game console we're used to seeing on a good PVM CRT monitor (or in the case of the Pi2Jamma -which I'm not a PCB/arcade guy for the record-, I assume would more closely mimic a PCB hooked up to a nice quality CRT arcade display). (hopefully that was what you were asking

OR, if you're asking if the funky non-logical 1600x240 pixel size setting is truly outputting 240p - with the HUGE front/back porch settings you put into the config file, yes, it outputs a proper 320x240 240p output at the end of the day (or a 256x244, or whatever that specific emulator/ROM calls for around 240p resolution).

[bobrocks95]

Is actual rendering changed to 240p? So then the filtering is being performed on a 320x240 image? Doesn't sound like that would look good at all.

The normal way of getting the Pi2SCART or the Pi2Jamma boards to work is a regular 320x240 (240p) hdmi_timings setting you put in the Pi's /boot/config.txt file. This is the default setting ArcadeForge recommends you use. It makes the Pi output a true 240p image which is what people want for these CRT monitors since the native games run at that resolution. BUT the filtering I'm talking about is then being performed on that 240p signal by RetroArch, which you're right in saying it doesn't look good at all. That's why if you follow the settings in the article I linked to it turns off all those settings and you then get a true unfettered, un-messed-with 240p image which closely mimics the RGB signal from a video game console we're used to seeing on a good PVM CRT monitor (or in the case of the Pi2Jamma -which I'm not a PCB/arcade guy for the record-, I assume would more closely mimic a PCB hooked up to a nice quality CRT arcade display). (hopefully that was what you were asking

OR, if you're asking if the funky non-logical 1600x240 pixel size image is truly outputting 240p - with the HUGE front/back porch settings you put into the config file, yes, it outputs a proper 320x240 240p output at the end of the day (or a 256x244, or whatever that specific emulator/ROM calls for around 240p resolution).

Yeah, that answers my question.

With a straight 240p image, pixel-perfect is definitely the way to go. There just isn't enough resolution to do even decent filtering.

Playing at the correct aspect ratio is nice though. But I think it would require a downscaling solution, with filtered ~1080p coming out of the Pi and then being downscaled to 240p for CRT display.

[awe444]

There's only maybe 6?-ish pixel clock settings allowed on the Pi 3 so when you're fine-tuning your CRT TV's display you're stuck with one of those - and the pixel clock setting anywhere around 240p is pretty crappy for 240p content

The Pi 3's lowest-possible pixel clock settings are constrained to be integer divisors of 19.2 MHz (see this page). Of those divisors, 6.4 MHz is closest to many of the classic 320x240p consoles/boards, which were mostly in the 6-7 MHz range (see this table).

To make this 6.4 MHz clocked signal look like standard NTSC, you want 263 lines/frame @ 59.94 frames/sec, so the number of samples per line should be 6400000 / (59.94 * 263) = 405.98. Rounding up to 406 makes the refresh rate a still close-to-spec 59.937 Hz.

It follows that the hdmi_timings line in your Pi's config.txt file should have:

-- 6400000 as the clock rate
-- (V front porch + V back porch + V active + V sync pulse) = 263
-- (H front porch + H back porch + H active + H sync pulse) = 406
-- You still specify 60 fps as the refresh rate but it will adjust it to the above specs making the signal 59.937 fps

For reference, here's the format of the hdmi_timings line, cited from this doc page:

Code: Select all

hdmi_timings=<h_active_pixels> <h_sync_polarity> <h_front_porch> <h_sync_pulse> <h_back_porch> <v_active_lines> <v_sync_polarity> <v_front_porch> <v_sync_pulse> <v_back_porch> <v_sync_offset_a> <v_sync_offset_b> <pixel_rep> <frame_rate> <interlaced> <pixel_freq> <aspect_ratio>

The individual porch and sync pulse values must be chosen/tweaked to produce the best image on your particular display. Note that the 406 samples per line accommodates not only H active of 320 but also 384, useful for a lot of arcade games, Virtual Boy, and other things. Here's the one that's worked for me:

Code: Select all

hdmi_timings=384 1 3 8 11 240 1 9 4 10 0 0 0 60 0 6400000 1

I've tested using the Gert666 VGA adapter with Lakka software on my Raspberry Pi 3, but the behavior should be same on Pi2Jamma and similar connectors since they use the same GPIO interface.

[jugu]

... I originally thought the image quality was absolutely horrible until I started to tweak these settings. I used this article as my base (I like the pixel perfect setting - especially for arcade) and I can switch back and forth from my consoles to the Pi 3, on the same game on the same level, and it's like ~90% identical (the ~10% difference is how the emulator is different than the actual console hardware - which is pretty minute to be honest - looks GREAT).

Which file are you editing to set the options as in the page you linked, https://www.hiscorebob.lu/tips-n-tricks ... -for-240p/ ? I just received my Pi2Jamma and it looks bad on my Egret 2.

Thank you!

[ralphnumbers]

The problem on all of these with the Raspberry Pi 3 is how the Pi is completely and utterly setup from the hardware to the [default] programming for HDMI output. I'm dealing with the Pi2SCART - but the basics for pi2Jamma is near identical in terms of display resolution.

The biggest hurdle seems to be the Pi 3's pixel clock (that's a big part of how you fine-tune all the settings to get the correct H sync and V sync in essence so it displays properly on your CRT monitor). There's only maybe 6?-ish pixel clock settings allowed on the Pi 3 so when you're fine-tuning your CRT TV's display you're stuck with one of those - and the pixel clock setting anywhere around 240p is pretty crappy for 240p content (which is like ALL/most of the arcade stuff, NES, SNES, Genesis, etc. etc. etc.). My CRT video output for example is a good 12-15% larger than any one of my 240p consoles - which probably isn't a problem if you're fine-tuning this for one single arcade cabinet, but for people like me it's a problem because I spent HOURS and hours setting up my BVM/PVM's so they look decent (not perfect) on any one of my 6 consoles and I'm not about to get into the service menus (or even adjusting physical pots INSIDE certain PVM's) to fine-tune my monitor for the Pi 3, then adjust it back again every single time I want to switch back and forth to/from the Pi 3 to/from my consoles - just not possible.

One workaround people just started using is a HUGE 1600x240 pixel size (regular is 320x240) with likewise huge front/back porch settings. This fools the system into using those limited pixel clock settings, while still displaying content correctly despite the limited amount of pixel clock settings, and the ability to properly scale and center the image. (totally in-theory as I still have to try this myself to see if it works as well as they say it does but it may fix some of the setup issues mentioned here).

Besides all that, the other half of these common problems is the RetroArch settings which are mainly setup for HDMI output which absolutely rapes the image quality on a CRT monitor. Most of the emulation software images people use will have RetroArch at the core (or the ones I've tested at least do - I'm a tried and true RetroPie man myself after trying several others). Basically you have to turn off all the HDMI-specific settings, turn off all the filtering and upscaling stuff, to get it to display a nice clean RGB signal. I originally thought the image quality was absolutely horrible until I started to tweak these settings. I used this article as my base (I like the pixel perfect setting - especially for arcade) and I can switch back and forth from my consoles to the Pi 3, on the same game on the same level, and it's like ~90% identical (the ~10% difference is how the emulator is different than the actual console hardware - which is pretty minute to be honest - looks GREAT).

Thanks for posting this. I had seen the suggestion a bunch of times trying to get the retropie config to roll out of an old component CRT. Until seeing your post I had no idea the reasons for such an approach. My setup is PI3-->GERT666-->Audio Authority 9A60--> JVC 21inch CRT. While it was simple to get a 320x240 display using either hdmi_timings, or the new support for 240P on the composite output, the scaling and scrolling issues this created for the emulators was really disappointing. Vertically things were great, but horizontally I ran into issues where scrolling distortions were really pronounced. The various console emulators were downscaling from NTSC, etc. It just isnt 1 to 1, and with the pixel clock limitations that this post and a few others I have found pointed out, sadly, it never will be. The old NES mode 256x224 has a low clock of like 5.3. Understanding that was the biggest breakthru, for weeks I thought the 9A60 was the limitation. So, knowing that, I looked more seriously into the whole 1600x240 thing. This gets the pixel clock way up high at like 32.0, but the TV didn't melt. Once I gave all the emulators a really distorted custom viewport around this resolution, using integer scaling factor of 5 from the originals, it produced what I can finally call an as near to perfect as the PI3 can get, 240p image on my TV the requires NO Smoothing to look 98 percent of the real thing. Anyone trying to get this config working in particular, 240p to an old CRT TV, this is your holy grail.

Take the time to customize the porch settings to be centered on your particular TV.

Now, the only issue this leaves me with, is an unreadable menu system. I tried the before and after scripts outlined by the pi2jamma folks to swap resolutions between games and the menu system, and while it does go from 320x240 to 1600x240 when entering a game, I can never seem to get it to return to 320x240 on exiting a game successfully. Any guidance there would be cool. Or maybe we can hope retropie will put some superwide mode for us weirdo's doing this stuff. Anyways, wanted to report my success with the 1600x240 mode.

[noonan2678]

Catching up on this...haven't had time to do any more testing. I've since acquired both the pi2SCART and the RGB-Pi, which is a straight cable from the Pi to a SCART end. I appreciate all the insight here. I'll likely be building a GroovyMAME setup over the summer, but these would be a nice, quick and easy solution. I've got both a Candy Cab and a PVM/BVM setup, so will end up testing both.

With so many pre-built images for RetroPi and HyperPi out there, it would be nice to be able to somehow edit the timings, resolution, etc. to be able to use those as-is. Has anyone experimented with that yet? Seems like most of this would be configurable via the config.txt file, based on the input given here so far.

[Dochartaigh]

Which file are you editing to set the options as in the page you linked, https://www.hiscorebob.lu/tips-n-tricks ... -for-240p/ ? I just received my Pi2Jamma and it looks bad on my Egret 2.

There is a file but I forget it's exact location. The RetroArch menu is what you can use – it's accessible through the RetroPie menu on the home page, then select RetroArch Settings, and once in there go into the Video sub menu and you'll see those settings that article is talking about (and remember to save when you're done)

If you're going to use the 1600x240 trick as well you might want each of the emulators to be individually setup with custom settings...if not individual games each to have their own settings even (still trying to figure this out myself). How you can do that is while playing a game hit Select+X to enter the RetroArch menu.

Now, the only issue this leaves me with, is an unreadable menu system. I tried the before and after scripts outlined by the pi2jamma folks to swap resolutions between games and the menu system, and while it does go from 320x240 to 1600x240 when entering a game, I can never seem to get it to return to 320x240 on exiting a game successfully. Any guidance there would be cool. Or maybe we can hope retropie will put some superwide mode for us weirdo's doing this stuff. Anyways, wanted to report my success with the 1600x240 mode.

I only had a chance to spend a couple hours on this 1600x240 tweak a week or so ago, but I was having the same issue. I thought it was just me as everybody on their facebook says it works perfectly, so I was going to reformat and start over... Maybe it'll work on a fresh system I haven't messed with all these settings on?

I'm also confused as to whether you literally have to tweak the custom viewport settings (and save that setting) for EVERY SINGLE GAME ROM you play (which is only a couple hundred on my system I actually ever play, although there's like 15,000+ games loaded I *might* want to play at some point). Consoles would be pretty simple as those are usually the same (or really close) resolution between most games on the same system for the most part, but Arcade/Mame resolutions are all over the place so one setting I don't think will work properly for all of them (thus HAVING to have every single game set up separately...maybe).

I'm just still saddened that you need all this work to do one simple thing on the Raspberry Pi with the Pi2SCART: shrink the image about 15%. With the default 320x240 timings, and the "pixel perfect" settings from that linked article everything is perfect on my system except the image is ~15% larger than any one of my 5 or 6 RGB consoles so the edges are getting cut off.