Recalbox sur TV CRT en RGB

[Substring]

I'm surprised that they get audio with the very few GPIOs left.

@ian57 can PWM be used on Pi3 ? would it be worth if we want a single GPIO2SCART cable ?

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@dcervi but he is not giving away the schematics

[dcervi]

@subs Nope. I think his intention is selling it. He already ordered some PCBs with smd components. He is working on a script to make RetroPie change resolutions on the fly.

It seems the perfect solution. We will see how it all works when(if) it gets released...

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@dcervi anything that is software we can handle at least as good as retropie. Too bad for his cable, i'm sure we can go through without it

[dcervi]

@subs Yes, I'm sure. But I'm curious to see how his solution works. Anyway, it shouldn't be too hard to deduce the schematics when it is released, as it should be using only resistors as the GPIO to SCART depicted on this forum.

He says he had to recompile some Raspberry Pi driver (¿overlay?), because the original VGA666 overlay interfered with analog audio on the Pi.

[Scandy]

@dcervi @subs I really don't get why an hardware device (this GPIO > SCART or PI2JAMMA) should be exclusively "linked" to Retropie or other distro.

[Substring]

@Scandy can you explain further your mind ? What is GPIO-dependant is linked to a Pi. And I intend to beat retropie on that CRT subject

[aTg]

Hello, I come to this forum because in other sites I have had many critics saying that I have not discovered anything new or that it was better to use an HDMI > VGA converter.

The first thank you for the interest and the valuation on your part, I have seen that all the questions you have are really interesting and I will try to answer them, sorry for the English I am using translator.

I am using RetroPie only for development since Recalbox is a buildroot and and it's harder to do tests but the idea once finished is to launch a patch or if the developers collaborate a specific version of Recalbox.

The first photo of the prototype is not the complete circuit. I have done this so that it would not be so simple to clone.

If I am thinking of selling it but for those who like to solder I thought of selling only the PCB so that each one builds his own cable at a much lower price and easier to do the circuit from scratch.(If you are patients in a little more than a week I will have the first PCBs)

The idea is that this is mounted inside the SCART housing

I also have the change of resolution for each emulator, there is the section of mame that needs another more complex system but that we can develop it with time, to see if the developers of recalbox help a little, they will get a cable so that it Try them out.

https://www.youtube.com/watch?v=KIVKS6rr4LQ

[ian57]

@subs Yep as the Pi zero, I think you can redirect the pwn on gpio... need to verify that from http://elinux.org/RPi_BCM2835_GPIOs. It is possible from 12/13 or 18/19 (http://raspberrypi.stackexchange.com/questions/49600/how-to-output-audio-signals-through-gpio), but these GPIO need to be free from the VGA666 used pins. To do that he has to use the mode 6 of the 666 (https://github.com/fenlogic/vga666/blob/master/documents/vga_manual.pdf) dpi_output_format=6 which leaves free the GPIO 18/19. He has to use dtoverlay=pwm-2chan,pin=18,func=5,pin2=19,func2=5 to redirect the audio signal to the pwm gpios.

Afert that a simple lowpass filter on these outputs as in the case of the pi zero https://github.com/recalbox/recalbox-os/wiki/Analog-Audio-Pi-Zero-(EN) and that's all

[ian57]

@aTg It is a VGA66 adapter + a simple PWM lowpass filter on GPIO 12/13 for the sound integrated on a scart board, isn't it ? Simple

The idea to make it as small as possible to be included in the Scart plug is good and elegant. But with the use of gpio, you need use USB pads or usb arcade encoder. The HDMI-VGA solution allows to use the GPIO for control panel.

Each solution has advantages and drawbacks.

[Scandy]

@subs I mean that when I'll buy the Pi2JAMMA and/or RGB-PI I really hope to not be limited to a single distro (e.g. RGB-PI working only on Retropie) but I really hope that it will be (software-side) "platform-independent".

@aTg your project is great, I really hope it will be also affordable for people who cannot solder like me. At the moment do you have a single resolution for emulator or different resolutions for each game? Thanks!

[Substring]

@Scandy some parts are OS-dependant, we can't avoid that ... Despite have the same goal, retropie and recalbox do it in different ways ... The hardware part can be done rather easily (buildroot is not such a freaky beast), but supporting this hardware to its full potential can be os-linked. Up to the developpers to make the best of it, limit wbat depends on the OS as much as possible

@aTg i'll answer you once i check a few things

[aTg]

@ian57 Very easy but no one had done it, besides it is necessary to compile an overlay specifically for it.

I am working on another version for jamma where you will also have a port expander with 32 inputs and power for the RPI included by the gpio. Of course also with sound and RGB.
This version is designed for crt televisions, not for arcade cabinets.

The one who wants to use this in an arcade jamma cab wait to jamma-pi

Each emulator (console) already has its own original resolution except mame.

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@aTg each crt console has several resolutions depending on the games ...

For arcade, i have an idea for standard horizontal games, not yet for vertical ones ... But anything that tweaks hdmi timings is os-dependant unless you write a wrapper for retroarch + some "database"

[aTg]

https://www.youtube.com/watch?v=g7tBX-DgD_g

[Substring]

Hey guyz,

I've been working really hard for 2 days for a Mame Resolution "DB", heree's an excerpt :

8080bw_drivers.c  einnings  0         m4            (8080bw)       ROT0         256x224
8080bw_drivers.c  shuffle   0         shuffle       (8080bw)       ROT90        256x224
8080bw_drivers.c  dogpatch  0         clowns        (8080bw)       ROT0         256x224
8080bw_drivers.c  spcenctr  0         spcenctr      (8080bw)       ROT0         256x224
8080bw_drivers.c  phantom2  0         phantom2      (8080bw)       ROT0         240x224
8080bw_drivers.c  bowler    0         bowler        (8080bw)       ROT90        280x224
8080bw_drivers.c  invaders  0         invaders      (8080bw)       ROT270       240x224
8080bw_drivers.c  blueshrk  0         blueshrk      (8080bw)       ROT0         256x224
8080bw_drivers.c  invad2ct  0         invad2ct      (8080bw)       ROT90        256x224
8080bw_drivers.c  invaddlx  invadpt2  invaders      (8080bw)       ROT270       240x224
8080bw_drivers.c  sitv      invaders  invaders      (8080bw)       ROT270       240x224

I could get 100% of Mame 0.78 resolutions by combining different sources. From that, we can do anything

[aTg]

It seems that we have been working on the same lately, I already have a prototype for arcade machines working, the look will be this one.

Characteristics:
Jamma connector
RPi power from the jamma connector
Over voltage protection and over current fuse
RGB 15kHz
A single filtered sound channel
Port Expander with extra button inputs
All in one pcb without any cable

[ajefr]

Already working
http://www.neo-arcadia.com/forum/viewtopic.php?f=14&t=54733

https://www.youtube.com/watch?v=v4pR3LKDCPw

[Substring]

@ajefr This is not exactly the same :

• RPI2JAMMA doesn't handle the sound out from GPIO, but from the jack output
• RPI2JAMMA is mostly for JAMMA, where as we are, for now, more looking into a SCART system
• I didn't get how you handle inputs

Do you have a documentation on how to plug everything ?

[aTg]

If my version incorporates the sound by the GPIO and is much smaller, I hope the opinion of the community if you think it interesting to continue with the development of jamma-pi or you think that with rpi2jamma is enough.