XRGB-mini Framemeister

[Konsolkongen]

Japanese MegaDrive 1. 59.91Hz, no stuttering and perfect V-sync on my Panasonic plasma.



EDIT: You can also remove 90% of the visible jailbars on all MegaDrive 1's by lifting a pin on the video chip. Add scanlines to that, and you pretty much end up with the perfect MegaDrive experience

Which pin?

Pin 50 on 315-5313. You can keep it floating or connect it to ground. I tried both and it doesn't make any difference what you choose.

If you lift this pin you will only get black and white composite video.

You can also follow my epic jailbar-quest here if you are interested:
http://www.assemblergames.com/forums/sh ... XA1645-mod

[BuckoA51]

Thanks Konsolkongen, this entire thread does all need documenting properly. Maybe it's time I got editing the XRGB Frame Meister Wiki.

[RGB32E]

Pin 50 on 315-5313. You can keep it floating or connect it to ground. I tried both and it doesn't make any difference what you choose.

If you lift this pin you will only get black and white composite video.

You can also follow my epic jailbar-quest here if you are interested:
http://www.assemblergames.com/forums/sh ... XA1645-mod

That's quite the quest..

I take it that pin 50 on the VDP is the subcarrier output? Seems like the HW engineers at Sega didn't mind routing the subcarrier signal next to the RGB lines, resulting in the jail bars. Most of the Saturn revisions have this issue as well.

Also, which amp were you referring to? Seems like 0.1uF caps would be required between the VDP and a NJM or THS amp...? Likely some DC offset that needed to be removed instead of amplifying!



Found the pinout - http://cgfm2.emuviews.com/txt/genvdp.txt

41 - VSYNC (Vertical sync) // ORLY?
42 - C-SYNC (Composite sync)
43 - HSYNC (Horizontal sync) // YARLY...
44 - HL (from control port HL pin)
45 - SEL0 (from M3 on cartridge connector - forces mode 4 graphics)
46 - PAL (PAL / NTSC select)
47 - RESET (68000)
49 - CLK1 (68000)
48 - SEL1 (?)
50 - SBCR // Subcarrier!!!
51 - CLK0

[Konsolkongen]

I take it that pin 50 on the VDP is the subcarrier output? Seems like the HW engineers at Sega didn't mind routing the subcarrier signal next to the RGB lines, resulting in the jail bars. Most of the Saturn revisions have this issue as well.

Right you are. I wasn't aware the Saturns suffered from this as well. It should be possible to do the same fix on those too. Perhaps I should try that on my COOL-Saturn, as it showed extreme jailbars on the XRGB-3 without LPF and none with LPF. The picture is great on the Mini, but my old VA0.5 Saturn had a slightly sharper image.

Also, which amp were you referring to? Seems like 0.1uF caps would be required between the VDP and a NJM or THS amp...? Likely some DC offset that needed to be removed instead of amplifying!

Sorry, back then I wasn't as kewl as I am now so I didn't know of the NJM and THS amps. What I used there was the old transistor amp for PC-engine which I modified several times to get the colors right:



For a while I thought it was THE BEST possible picture I would ever get from my MegaDrive, and though it was pretty good, I'm glad I was wrong. The image with my amp was slightly less sharp and I did have a lot of problems with colors changing when the colored area expanded on the screen (makes sense?).
Someone actually mentioned in the tread that the subcarrier was likely to blame, but I was so sure that the CXA1145 was to blame (because when I swapped Blue and Green input/outputs the green colors had the jailbars). If only I had my Neo Geo CD at the time I would have known that the CXA1145 is easily capable of producing perfect jailbar-free RGB outputs...

But I did learn a thing or two, and knowledge is power!

[BuckoA51]

My Genesis that was giving the weird vertical sync issues, I opened it up, this is what I found:-



WTF ? Why does the motherboard say PAL on it? Has someone swapped out the motherboard at some point or could Sega have had a glut of PAL boards they just converted to NTSC? Or does the PAL on the board here not relate to the machines region?

Weird indeed!

[Fudoh]

What's that extra IC glued down in the middle ? And what's with all the random cables ?

[Konsolkongen]

Most likely a modified version of the Saturn's Ultimate-mod that changes region by holding the reset button. It has been adapted for MegaDrive and SNES, and possibly other systems as well.

[BuckoA51]

Exactly right, its the region/hz switchless mod, the two wires going to the expansion connector also switch region on the MegaCD...but yeah, why does it say PAL?! this is a Genesis!

[Konsolkongen]

I assume you bought it modified then? It seems like someone swapped the insides of a Genesis with a PAL motherboard.

The oscillator in your PAL MegaDrive is most likely 53.203424 MHz. Remove the black tape to make sure. I guess you could make your PAL MegaDrive run the same refresh-rate as mine by swapping the oscillator with a 53.693175 MHz which is what the NTSC models use.

[BuckoA51]

Weirdly no, I bought it unmodded then sent it off to be modded. Unless the modder swapped the motherboard (unlikely) I guess we'll never know. I can't solder for crap so I'll just grab a Japanese megadrive and get it re-modded.

Anyway, if you're planning on using a Megadrive with your Framemeister, you're a lot better off with a genuine NTSC one it seems.

[Konsolkongen]

The slight oscillator differences is probably the reason why I get stuttering when playing 50Hz on my JAP MegaDrive and Saturns too.

My EU SNES is a 1-chip and I had to install a second crystal for 60Hz, so now it does "proper" 50hz and 60Hz totally stutter free.

[BuckoA51]

Installing a second crystal, interesting idea. I've not noticed any problems on other consoles though, the 50hz stuff might be slightly out of spec on my NTSC Saturn but not far enough to cause difficulty, I don't think (though I haven't played PAL Saturn stuff in ages).

I'll investigate further!

Yep, as I remembered 50hz is fine on the Super Famicom and the Saturn, at least on my TV. That really only leaves the Amiga that won't V-lock at 50 and 60hz. If only NTSC Amiga's weren't so rare!

Edit 2 - There's also some discussion on changing crystals to alter refresh rates on Neo Geo hardware here http://www.neo-geo.com/forums/showthrea ... fresh-rate , but no indication of if this was ever successfully done.

[Konsolkongen]

Yep, as I remembered 50hz is fine on the Super Famicom and the Saturn, at least on my TV. That really only leaves the Amiga that won't V-lock at 50 and 60hz. If only NTSC Amiga's weren't so rare!

On your TV only or using the Mini? 50Hz works fine on both my MegaDrive and Saturn, but for some reason it stutters a bit when playing through the Mini (firmware 1.06 of course). The picture is also brighter than normal which is weird

[BuckoA51]

Oh sorry, I only tested with XRGB3+DVDO Edge as I've not gone onto the PAL firmware on the mini yet, but if the Edge can V-lock it I see no reason why the Mini could not?

[Konsolkongen]

I think that when I used the same chain the EDGE V-sync locked fine with the JAP MD and SAT consoles in 50hz as well. But as I have sold my XRGB-3 I can't confirm this

[BuckoA51]

Ah, maybe the delay in the latest firmware is so that these bugs can be addressed then.

[Konsolkongen]

I guess we'll never know. I can't solder for crap so I'll just grab a Japanese megadrive and get it re-modded.

Forgot to comment on this. Do that! Not only does the Japanese MegaDrive 1 have a square cartridge slot so it takes all game regions, it also has a larger 16-bit logo which looks much cooler

[Yamato]

New firmware 1.07 out now

[Zapf]

Cool, I guess they know about the mega drive interlaced video issue.

[BuckoA51]

Some very interesting features.. CLASSIC_MODE機能追加（CRTの - wonder what that is?

[Fudoh]

trying now! (english works again btw)

[BuckoA51]

I don't know how Micomsoft have done this but... they've actually reduced the stutter on the Amiga at 60hz to where it's barely noticeable! This could mean big improvements for Neo Geo too.. So far the PAL handling is also flawless.

[Fudoh]

Classic Mode adds shadows to the left and right side of the visible image. Tries to emulate the reduced brightness on the edges of a CRT monitor. Kinda weird on a LCD, a bit like heavy banding...

And with the 2x2 Wall mode I guess I need 4 displays and 4 Minis now

[Fudoh]

No PAL source on hand, but I guess scanlines on 288p still like odd, don't they ?

[pyrotek85]

Awesome, gonna try it out. I've been using 1.5 since I'm still new to using it and needed English menus.

[BuckoA51]

Yeah scanlines on 288p are totally broken! Otherwise a very good showing for PAL material, currently the only stuttering was on the Super Famicom, that's a NTSC console forced to PAL anyway, but it doesn't stutter on the XRGB3+DVDO Edge combo.

Edit - PAL and NTSC interlace on the Saturn (as on the Radiant Silvergun title screen) was not recognised correctly, yet on the Amiga it was (and deinterlaced very nicely, flicker free Workbench ftw)

[Konsolkongen]

Sweet with a new firmware! The Retro-mode is pretty cool. Not sure it's something I will be using, but I think it looks pretty cozy It has a bug though, when you use scanlines at 100 (as I do) they completely disappear in the left and right sides of the screen where it darkens the picture. That looks pretty strange.

EDIT: You actually have to lower the scanline setting to ~70 to get lines all the way through.

I can't imagine why they added the color-invert option, but I appreciate the effort and that's how I will be playing all my games from now on.

TV-Hotplug OFF/ON which is supposed to be the faster one?

I don't know how Micomsoft have done this but... they've actually reduced the stutter on the Amiga at 60hz to where it's barely noticeable! This could mean big improvements for Neo Geo too.. So far the PAL handling is also flawless.

Will hook up my MVS now to see if the stuttering has improved.

[Konsolkongen]

I don't know how Micomsoft have done this but... they've actually reduced the stutter on the Amiga at 60hz to where it's barely noticeable! This could mean big improvements for Neo Geo too.. So far the PAL handling is also flawless.

Will hook up my MVS now to see if the stuttering has improved.

The MVS still has that "3 thicker scanlines bug" where the Mini sees it as 241p rather than 240p and then can't evenly place the scanlines on the screen. This however is still easily fixed by changing V_width to 33 (+1). Stuttering hasn't decreased on the MVS, and I hate to say this but I actually think it has increased a tiny bit. It's still negligible and syncs just fine of course, but I think the stuttering is happening a bit more often than before. Still nothing I can't live with though.

EDIT: Actually I think this may be because of my new Yamaha AV receiver I'm running the Mini through. My Neo Geo CD runs at a strange 59.59Hz refresh and has always been totally smooth on my TV. It too stutters a tiny bit when running the Mini though the Yamaha AVR, but runs 100% smooth when connected directly to the TV.

So nothing has gotten any worse in the new Framemeister firmware as far as I can tell

Now to see if I can make the stuttering disappear when running it though the AVR. Hmmmmm...

EDIT2: Now the NGCD>Mini combo is running 100% smooth through the AVR. Not really sure what's going on here
Could it be that the Mini stored the EDID information from the TV?

[BuckoA51]

Ah yes the Amiga has the same bug with the thicker scanline too, also recognised as 241p. Strange you should think the stuttering is worse, before this update the Amiga @6ohz would stutter and throw those white lines across the screen (same as XRGB3 + DVDO Edge did), now the stutter is barely noticeable and the white lines are gone. Maybe it's different depending on the TV in use...I know I'm pretty chuffed anyway

I hear it's actually possible to use an external video clock with the Amiga, this was included for Genlock compatibility, though I've not got the technical know how to try it out.

[Konsolkongen]

No I actually think it was a problem with the AVR I'm running the Mini though. The stuttering was a bit worse on the MVS so I just checked the NGCD which has a strange refresh rate as well but never stuttered on my TV at all. It too did stutter a little bit
So I connected the Mini to the TV directly and the stuttering was gone. Then I swapped cables HDMI output cables on the Mini to run it into the AVR again, but without turning it off first (shame on me ), and now there was no stuttering. I then used the "EDID get" option which I think stores the EDID information on the Mini itself. The information that was stored was probably that from the TV since I just swapped cables without turning it off. Since then it actually seems to work perfectly again.

I'll try the MVS again and I expect the stuttering to be slightly less noticeable now

EDIT: It is. MVS was working fine all along