What's new
By:

RaspberryPi to JVS

PascalP

PascalP

Legendary
Joined
Jan 17, 2016
Messages
5,634
Reaction score
3,770
Location
The Netherlands
As there a quite a few topics on multiple forums about connecting a RPi to a Jamma cab, and mutiple sellers for pre-configured setups, I think it should be more then capable to run 15k games like CPS2 and MVS (especially the RPi3).
But all of these topics focus on connecting a RPi to a Jamma cab via an extra PCB etc.

What I would want, is to use a RPi connected directly to a JVS cab in native 15k via VGA (e.g. New Net City, Namco Cyberlead).

- Power;
Shouldn't be an issue in any cab

- Audio;
Connect to my stereo amp via the 3.5mm jack to RCA

- Controls;
Connect to USB via a JVSPAC

- Video;
Connect to VGA directly via either of these products;
https://www.pi-supply.com/product/gert-vga-666-hardware-vga-raspberry-pi/
or
https://thepihut.com/products/raspberry-pi-hdmi-to-vga-convertor

My guess would be a HDMI to VGA converter could add lag, so my preference is the VGA 666 board.


What are your thoughts and does anybody has some good source on how to setup the SD card or perhaps even share a image of a pre-configured SD card?
 
werejag said:
why use a JVSPAC can it be implemented via pio
Click to expand...
Perhaps it could be, but as I already own a JVSPAC it seems like it's plug&play for me ;)

But if it works to add a USB connecter to the GPIO directly for JVS it would even be easier!
 
Unless you adapt the inputs directly to GPIO and skip JVS (are there even enough inputs?), you're going to require both extra hardware and software to drive JVS. JVSPAC is probably your simplest option since it presents itself to the RPi as a HID device, right? It also manages the JVS protocol and you don't have to worry yourself with the ins and outs of JVS. There's no way you'd be able to get it to work wiring a Type A USB adapter directly to GPIO, as you'd at least need some kind of TTL to RS485 converter. Even with the appropriate hardware in place, then you'd need software that drives the JVS board and translates it to usable inputs for the RPi. I just don't see that being a super simple solution. If someone hasn't already come up with that software, you're doing it from scratch.
 
Last edited:
That RS485 board Twisted Symphony is referring 2 is a piece of junk. RS485 drivers need their transmitter enabled when you intend to send a datastream. That pcb simply uses the bits from the data stream to enable the transmitter. So half of the time, the bus is tristate again instead of being driven by the rs485 transmitter. This works for short distances and if the 2 rs485 lines are pre polarised with resistors, but it's not the way things should be done.
Raspberry pi 3 uses it's uart to drive the bluetooth module. The gpio serial port is something unreliable. You can revert it back like it was before, but in that case your bluetooth becomes unreliable. So, it's either a good bluetooth interface or a good uart interface.

The raspberry pi analog output is bad as well. If you use a hdmi2vga adapter, it might have an analog output with a better quality. The pi analog audio output is known to be noisy and the signal levels are lower than standard.

The gert-vga uses up a lot of the free io lines and the impedance of the 3 color inputs need to be identical. It uses a simple ladder resistor network as low cost digital 2 analog converter without buffer amplifier. So, a lower impedance on one of the color inputs will decrease the signal of that color resulting in incorrect colors.

FTDI sells some USB 2 RS485 adapters, but they are expensive (around 25 euro)They also sell a cheaper module (5 euro) that has the ttl io lines brought out. You would still need a small additional pcb with a rs485 driver chip like the 75176 to have an usb to rs485 solution. The advantage of such approach is the fact that it can be used on a x86 pc as well. The module has a line that can be programmed as transmit enable for the rs485 driver chip so it works the way it should. That transmit enable line is controlled by the chip, so you don't need some special programming for it. It behaves like a normal serial port.
 
To be fair, if you're looking at using a pi for emulation you probably don't care much about the quality of the results to begin with.
 
I assume the basic driving factor to use the pi is price.
Only later, people realise that it comes without supply, storage and input devices.
Never the less, it's advertised with an analog audio output, so you expect the same quality you get from a pc audio output...
The nes classic mini is not much more than a raspberry pi and it's sold out everywhere. So, for emulation of older systems, it should be fine I assume.
 
After reading all your comments I think the Pi might not be the best solution for me...
Quality is very important to me, the driving factor for this is easy and 15k.
I prefer to play all my games from original hardware, but some of the really expensive CPS1.5 stuff I play on a PC running Lakka in 31k.
Looking to get a good 15k replacement for that.
 
If you have the space in your cabinet, buy a second hand pc. Conrad sells some pretty cheap with not to bad specs (like 120 euro)

So, if I understand correctly, you have a JVS interface in your cabinet. I am just a bit confused about it's monitor options.

Figure out about the methods to switch the pc to 15k resolution. See if the vga signal levels are good for your monitor. (VGA uses 0.7V ptp and arcade monitors used 5V ptp video signals.) VGA has 75 ohms impedance and arcade 1K or higher.

With that, you will be able to get the most accurate emulation (besides the real hardware.)

But, that's just my opinion.
 
twistedsymphony said:
PascalP said:
Quality is very important to me, the driving factor for this is easy and 15k.
Click to expand...
you might consider reading my guide on this topic if you haven't already: http://solid-orange.com/1476
Click to expand...
Had a good read, and;
Option 3: CRT_EmuDriver & Atom-15 looks like the way to go :)
I actually have all the parts needed (Core2Duo 6700 and a HD45xx card)

I will give it a go over the weekend to flash the card.
Any good guides for setting everything up in GroovyMAME/Rocket Launcher?
 
for GroovyMAME:

1.install crt-emu driver with these steps: http://geedorah.com/eiusdemmodi/forum/viewtopic.php?pid=334#p334
2.install groovymame like normal mame and get your roms in place (you'll need these to determine video modes)
3.install and setup Video Mode Maker to generate the necessary video modes/configure mame: http://geedorah.com/eiusdemmodi/forum/viewtopic.php?id=46

wait until VMM has configured GroovyMAME before you go tweaking your settings there. it's also a good idea to save a backup of the config.ini file after running VMM and before you start making your own adjustments.

For Rocket Launcher
1. Instal your front end of choice
2. install rocket launcher (this also shows hyperspin but you can replace those bits with your own front end):
3. setup rocket launcher:
 
You must log in or register to reply here.
Back
Top