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Raph_friend

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The direct output method was made for people that don't have access to a I/O PCB, the last one you will have video ouput directly from FPGA, it means no interference from external signal.
Using @invzim logic means that VGA from I/O won't ouput the full range of colors from original system.
 

invzim

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The direct output method was made for people that don't have access to a I/O PCB, the last one you will have video ouput directly from FPGA, it means no interference from external signal.
I'm sure the HAT approach is ok, and we may be entering into hi-fi phoolery territory. The colors via direct_video is also directly from the FPGA and with has no interference. The core toggles the pins (all 24 of them :)) going into the ADV7513, which in turn turns transmits these via 4 diffpairs exiting via the HDMI connector. The HDMI dongle picks up these bits and runs it through a DAC. The ADV7513 does not do any processing of the video. I.e. it's digital all the way from FPGA to the DAC portion of the HDMI dongle, without any processing - that's the thing with the direct_video feature, while the old/normal HDMI processing will process the video into a suitable standard resolution.

To sum up, HAT:
GPIO pins -> Resistor ladder, 18 bits
direct_video with Dongle :
GPIO pins -> ADV7513 -> HDMI dongle DAC

1613494606913.png
 

Raph_friend

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The funny thing is that you are answer yourself.

If we have a processor for DAC, we already have interference even directly from FPGA, it's basic about signal processor.

Again, and it come directly from sorg, the idea about direct video method is give people that don't have a I/O board the taste of RGB.
 

invzim

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The funny thing is that you are answer yourself.

If we have a processor for DAC, we already have interference even directly from FPGA, it's basic about signal processor.

Again, and it come directly from sorg, the idea about direct video method is give people that don't have a I/O board the taste of RGB.
If you believe that a DAC built from 18 resistors is superior to a purpose built IC because sorg said so, I have nothing more to add :D
 

Epyc

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Is there a visual comparison between the 2? I’m interested what the optimal config would be.
 

Raph_friend

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If you believe that a DAC built from 18 resistors is superior to a purpose built IC because sorg said so, I have nothing more to add :D
So you know more about MiSTer project than the creator? Interesting.
 

KalessinDB

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Is there a visual comparison between the 2? I’m interested what the optimal config would be.
Afaik the argument here is deep in the weeds. Double blind, no one is going to be able to reliably tell the difference between 18 and 24 bit color, let alone during actual gameplay.
 

rtw

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Does anyone know how the upcoming MiSTercade handles the DAC issue as well as the amplification to RGB "JAMMA" levels ?

 
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Dloop

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Does anyone know how the upcoming MiSTercade handles the DAC issue as well as the amplification to RGB "JAMMA" levels ?

No idea, but since it's a "hat" I am assuming it also is using the GPIO ports so having the same limitations as the VGA out today?
 

rtw

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No idea, but since it's a "hat" I am assuming it also is using the GPIO ports so having the same limitations as the VGA out today?
I understand that it's using the GPIO for the RGB.

What I am wondering, is how the JAMMA RGB levels are created ?

From pictures found online of the MiSTERcade I see the resistor ladders but I do not see any buffers or similar.
 

ShootTheCore

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I understand that it's using the GPIO for the RGB.

What I am wondering, is how the JAMMA RGB levels are created ?

From pictures found online of the MiSTERcade I see the resistor ladders but I do not see any buffers or similar.

I’m one of the beta testers for the MiSTercade. From what I can tell, it’s using a resistor ladder off the GPIO pins. The documentation states that the RGBS levels are ~3V.

The hardware is still a work in progress and we want it "done right" so if you want me to measure something specific with my scope, or if you have suggestions to pass along to the creator, let me know.

C4CB09FC-F5B6-4FA9-984D-A22860998700.jpeg
 
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nem

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This looks promising... a box that lets you use Namco Guncon/GCon45 lightguns with any core: https://misterfpga.org/viewtopic.php?t=2143&p=19489

That's really cool. MD Menacer and SNES Super Scope are straight up trash, but there's a few decent light gun games on both platforms.

EDIT: since I'm here in this thread, I might as well ask. A friend's bringing me a MiSTer to try out on the weekend. It's just the DE10-Nano board I think? Well, let's say it is. What core runs without any extra memory?
 
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SNK-NEO-GEO

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@nem - try to get the I/o as well because the mister shines on CRTs at any video out put..

also, I find it better/less lag to connect the usb joystick directly to the de10 board used the OTG to usb cable.
 

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98pacecar

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What's the best place to buy a complete setup in the US? I see that misteraddons.com is out of the main board most of the time. Really just looking for the DE-10, standard IO, USB, and RAM. Nothing fancy at this point.
 

pacoarcade

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@awbacon1 I highly recommend using a protective case to avoid ESD accidents and physical damage.

Neptune case from Nat is great!

mister-fpga.jpg
 
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