Voltage levels in JP21

[EmperorZelos]

I am curious at the JP21 contact, working with framemeister. I have cable that works for the framemeister iwth euro-scart so no need to tell me that. This is merely curiosa in case of things, but mostly just because I love knowledge!

I know euro-scart uses the composite video for sync signals and the composite video maxes just above 1V, but I know that JP21 uses a pure-sync signal so I am curious, what voltage does the sync signal of pin 9 for JP21 have? I have tried googling but that was an utter failure

[Fudoh]

The official JP21 console cables I know of (Saturn, Playstation, Super Famicom) all use the standard composite video signal for RGB Sync, so I guess that the specs are just the same as on the European version.

[RGB32E]

I am curious at the JP21 contact, working with framemeister. I have cable that works for the framemeister iwth euro-scart so no need to tell me that. This is merely curiosa in case of things, but mostly just because I love knowledge!

I know euro-scart uses the composite video for sync signals and the composite video maxes just above 1V, but I know that JP21 uses a pure-sync signal so I am curious, what voltage does the sync signal of pin 9 for JP21 have? I have tried googling but that was an utter failure

http://wiki.superfamicom.org/snes/show/ ... nd+Pinouts

Japanese 21-pin RGB Connector (EIAJ TTC-003)

This is the Japanese RGB connector used on many video game systems. It is physically identical to the European SCART / Péritel / Euroconnector with a different pinout.
|------------------------------------------|
| 2 4 6 8 10 12 14 16 18 20 |
| / 21
| 1 3 5 7 9 11 13 15 17 19 |
|-----------------------------------------

1: Audio Left Channel Input 2: Audio Left Channel Output
3: Audio Ground 4: Audio Ground
5: Audio Right Channel Input 6: Audio Right Channel Output
7: Sync / Video Ground 8: Video Ground
9: Sync / CVBS Input 10: CVBS Output
11: AV Control Input / +5v 12: Ym Input
13: Red Signal Ground 14: Ground
15: Red Signal I/O 16: Ys Input / 1V
17: Green Signal Ground 18: Blue Signal Ground
19: Green Signal I/O 20: Blue Signal I/O
21: Plug Shield / Ground

There's the pinout on GamesX as well - http://gamesx.com/wiki/doku.php?id=av:japanese_rgb-21

[RGB32E]

The official JP21 console cables I know of (Saturn, Playstation, Super Famicom) all use the standard composite video signal for RGB Sync, so I guess that the specs are just the same as on the European version.

Sort of? I believe the official Super Famicom and PAL SNES RGB cables have differences. The SFC cable has 220uF caps on the RGB lines, and the PAL SNES cable has termination resistors on the RGB lines. The official SCART GameCube cable is different from both of the 16-bit cables!

User Link83 made this thread to track all the differences between official AV and RGB cables Nintendo made:
http://nfggames.com/forum2/index.php?topic=3203.0

[EmperorZelos]

CVBS (Composite Video) in and out: 1 Vp-p, 75 ohms, sync: negative

So i understand, it is 1 Volt peak to peak value on the 9th pin of sync?

[ruger]

So i understand, it is 1 Volt peak to peak value on the 9th pin of sync?

AFAIU the sync signal should be between 0V and -0.3V for pure "video level" sync. In a composite video signal the "black level" starts at 0V and goes to "white level" at 0.7V - in total 1Vpp with the sync below.

I am not aware of any equipment that output "pure sync" at video level. Most equipment, including game consoles such as the US/JPN version of Saturn and Super Nintendo that output pure sync, output C-SYNC at "computer level". Computer level sync is 5Vpp. In practice that works fine with RGB21 input too - at least with the XRGBs.

[EmperorZelos]

so what level si the japanese sync in JP21 at then? 0,3V or 5V?

[ruger]

so what level si the japanese sync in JP21 at then?

My answer would be:
1Vpp as part of a composite video signal.

AFAIU the RGB21 is a "video level" connector. There is a LM1881N or similar chip that strips sync from video inside equipment with RGB21 sockets. In theory "computer level" level (5Vpp) sync is out of spec for many of these chips, including the LM1881N, but in practice I have never seen any problems.

So in theory I believe the "pure sync" level is 0.3Vpp for RGB21/JP21 - but this is a very theoretical answer for only the sync component of a composite signal that is expected.

Western equipment expects the same sync level if you feed a SCART socket (pin 20), the composite SYNC input on a DVDO Edge, or set the BNC inputs on your Lumagen to "SCART" instead of RGBS. However, the signal would normally not be "video sync" alone, but as part of a composite video 1Vpp signal. In practice I have never had any problems feeding any equipment TTL level sync, just as the LM1881N, but in theory one should reduce TTL "computer level" sync to "video level" sync by adding a resistor on the sync line.

[EmperorZelos]

So 1Vp-p? Thank you