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Home Arcade System

RGB said:
I promise you we're getting there, but the production is taking longer than I anticipated :(

Sneak peek at the second V5 prototype.
53571821179_c4b94d2533_z.jpg
Click to expand...
That's looking really attractive 😍

Any difference compared to the V4?
 
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@RGB will this version have the possibility to output completely unfiltered sync ?
 
@shelcoof , it's a complete redesign. I don't want to reveal too much just yet, but I'm sure you'll appreciate the new features.

rtw said:
@RGB will this version have the possibility to output completely unfiltered sync ?
Click to expand...
Raw/unbuffered JAMMA CSync output is available, but it goes through a 470R resistor as a safety measure in case somebody uses the TTL CSync setting with consumer equipment.

I implemented the 4-way joystick restrictor gate emulation you asked me about so many years ago :)
 
RGB would you mind explaining buffered vs unbuffered vs regenerated sync?


I'll give you an example. I was working on a Rastan Saga PCB recently testing on my crt TV with the HAS switch set to buffered as I normally do. The board had a fault with completely bad sync (turns out a clock divider IC was bad and it was sending a 31k signal to the sync instead of 15.7k).


Anyway, I replace the bad IC and was now getting a 15.7 on the sync measuered on he scope. However the sync would still drop for a few frames every second.

After much investigation, I decided to try the PCB it in my jamma cab lo and behold the sync was fine.

So I went back to the HAS and changed the switch first to "unbuffered" - same problem with a few frames of sync drops every seconds. But then switching it to "regenerated" and it worked fine now on the crt TV!

What causes this? Do any of the settings add any lag to the display?
 
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MickyMac said:
RGB would you mind explaining buffered vs unbuffered vs regenerated sync?


I'll give you an example. I was working on a Rastan Saga PCB recently testing on my crt TV with the HAS switch set to buffered as I normally do. The board had a fault with completely bad sync (turns out a clock divider IC was bad and it was sending a 31k signal to the sync instead of 15.7k).


Anyway, I replace the bad IC and was now getting a 15.7 on the sync measuered on he scope. However the sync would still drop for a few frames every second.

After much investigation, I decided to try the PCB it in my jamma cab lo and behold the sync was fine.

So I went back to the HAS and changed the switch first to "unbuffered" - same problem with a few frames of sync drops every seconds. But then switching it to "regenerated" and it worked fine now on the crt TV!

What causes this? Do any of the settings add any lag to the display?
Click to expand...
Sure, this is how it works:

Unprocessed:
JAMMA CSync -> inline 470R resistor -> output

Buffered:
JAMMA CSync -> Schmitt trigger -> inline 470R resistor -> output

Regenerated:
JAMMA CSync -> Schmitt trigger -> ISL59885 -> XOR gate to combine H/VSync from the ISL59885 -> inline 470R resistor -> output

There is no lag. Your TV is likely incompatible with the Rastan Saga's CSync, and the ISL59885 Auto-Adjusting Sync Separator fixes it.
 
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