Full VGA Support For Modchips! Options

[FrostyTheSnowman]

LOL, that's honestly the first time i've been asked that...

Here's my reasoning:

1. The X2 5035 is a full-featured BIOS, compatible with all XBOX versions that support VGA (1.0-1.5)

2. All modchips (not just Xecuter ones, unlike the X3 BIOSes) with a 512k or 1MB bank can use it (including v1.0-1.1 TSOPs)

3. It has an easy-to-use configuration file (all other BIOSes need to be modified using either EVtool or XBtool)

4. Xecuter BIOSes seem to be the most popular overall

So, the X2 5035 not only covers all the most important features in a BIOS, but it was also the easiest to modify and hack. (in my experience, the Xecuter BIOSes are the most friendly to hacks)

Although, the EvolutionX team makes a great BIOS too. I may be releasing an Evox M8+ version with my most recent VGA hacks pretty soon.

This post has been edited by FrostyTheSnowman: Oct 13 2007, 06:44 AM

[bobbyblaze]

Hey Frosty, any news on the vga lead?

[smoke_screen_uk]

Hi everyone,
not been about for the last month or so due to being very busy on my electronics degree.
Was just reading over a few of the recent posts here and noticed this one...

Punmaster has right that LM1881 has not standard h-sync signal but v-sync ist standard. I looked on the datasheet of the LM1881. On Pin1 the LM1881 output is c-sync (composite sync). Some displays cannot extract h-sync from the c-sync signal. But we can extract h-sync from v-sync and c-sync with a logic circuit.

NetFraggle went on to explain how it could be possible to create an H-Sync signal using the V-Sync, C-Sync and some NAND gates.
This solution may work ok, though I feel there is a better solution.

The LMH1980 and LMH1981, successors to the LM1881.
I think I've mentioned these chips before but this time I thought I'd add the Pinouts this time so that people could see what I was talking about.


LMH1980 on www.national.com
LMH1980 Auto-Detecting SD/HD/PC Video Sync Separator Datasheet
Application Note 1618 LMH1980 Evaluation Board Instruction Manual
Application Note 1681 Design Migration from the LM1881 to the LMH1980




LMH1981 on www.national.com
LMH1981 Multi-Format Video Sync Separator Datasheet
Application Note 1599 LMH1981 Evaluation Board Instruction Manual

As can be seen from these two chips, they both provide H-Sync out. They also do not encounter the same problems as the LM1881 with Rset, which needs to be chosen in relation to the video format being used.

On the downside, unfortunately as these chips are both new devices, they come in very small outlines (chip sizes) so they are not easily used by hobbiests. However, there are evaluation boards available on the national semiconductor site which can often be ordered as free samples.

I will be ordering all of the above components soon and be trying them out at university (because I can use the electronics workshops there). I will be sure to post back with my findings.

Keep up the great work everyone, hopefully we'll see all the minor issues ironed out in the not too distant future.

[bobbyblaze]

Hey Frosty!

Just wanted to say a big thank you for all your hard work. Plugged the xbox into my CRT projector with the component lead running 1080i RGsB and the little black box blew me away. Really stunning and the output puts my 360 to shame. Screw MS for not giving us 1080i VGA on the 360 Totally impressed at how mint the xbox looks.

Cheers Mate!

[FrostyTheSnowman]

Hey Frosty!

Just wanted to say a big thank you for all your hard work. Plugged the xbox into my CRT projector with the component lead running 1080i RGsB and the little black box blew me away. Really stunning and the output puts my 360 to shame. Screw MS for not giving us 1080i VGA on the 360 Totally impressed at how mint the xbox looks.

Cheers Mate!

Hell yeah dude, i'm always happy to hear that people enjoy my work. You guys are the very reason why i've created so many VGA utilities.

I honestly think that Microsoft really hurt the original XBOX by not allowing it to produce VGA, because being able to play original XBOX games in native VGA really is a beautiful thing.

To answer your earlier question though, I do not currently have an update on the cable... I haven't heard from my contact over in China in over a month. At this point i'm not sure what the future holds for my cable, but I promise you guys will be the first to know.

This post has been edited by FrostyTheSnowman: Oct 21 2007, 12:43 AM

[patch6]

Would a voltage attenuator like the following be fine for reducing the voltage that results in the extreme white tint / white clipping that Punmaster's LMH6739 circuit is supposed to fix?

[yaywoop]

hmm. interesting.
the only thing about voltage dividers is that they change under load. as long as the load is always 75 ohms, it should work. you might want to check that your screen does actually have a 75ohm termination, or account for any difference by changing resistor b.
to me it looks like its worth a try. someone correct me if we are missing something...

for things like this it would be handy to have an oscilloscope

[FrostyTheSnowman]

Alright, just for the fun of it I just ordered 5 samples of the LMH1980 sync-seperators from smoke_screen_uk's post, and all the parts necessary to attenuate the signal with patch6's diagram... i'm willing to bet that this will produce a perfect VGA cable.

I'll get back to you guys in a week or so when the parts arrive.

[patch6]

Here are a couple of test patterns to determine video quality (probably through XBMC's picture viewer). White clipping causes the grey grid in this picture to disappear:

It also causes the grey bar on the left of this image to turn bright white:

And finally, the grey scale on the bottom of this picture loses 4 shades of grey to it:


I wonder if hooking a second monitor up to the output with a Y-splitter will weaken the voltage enough to remove the clipping.

Going to try an attenuator with a transfer function of .458, requiring a 66 ohm resistor and two 200 ohm ones for each channel (not 100% exact, +-2 ohms off), before trying that. An .8755 one didn't make a noticable difference, and neither did a .6-ish one (lost the calculations, but it was something like 33 ohms to 330).

[w0g]

Any news frosty?

[FrostyTheSnowman]

I'm honestly not sure what is going to happen with the commercial version of this cable. I'm really not even sure there is enough demand for it to sell...

It's strictly a non-profit thing for me, so i'm not sure how the marketing/production side is really going...

For now though, if anyone out there wants a custom hand-made one, just let me know. (hand made ones are obviously not non-profit though)

NOTE: This is a new cable design, which includes a 1+3/2+3 mode toggle switch. (for Linux/Games)

Here's a picture of my current design: (sorry about the quality, it's a camera phone)






NOTE: I will only be building these cables by hand for people for a short period of time. (because they really are a pain in the ass to build)

First come, first serve.

This post has been edited by FrostyTheSnowman: Nov 25 2007, 09:44 AM

[bobbyblaze]

Hi Frosty!
Lead looks sweet and I'd like to get one but any chance of co-ax digital out for audio (pleeeeeeeeeease )?

[Foe-hammer]

I do believe there still is a niche market for the vga cable. I'd buy one, even though i already have one that i made, just to have another one.

[RayTwoOneThree]

Hello i was wondering if someone out would be willing to make a cable for me or sell one in they have a extra one. I would be very thankful if you did. U can just pm me with your info and a photo of the cable. And we got a deal. Thanks...

[redpacman]

How does this look?

This is what the manufacturer said the packaging would look like.

Oh yeah, and they also said it would be easy to implement, and shouldn't raise the price.

I will know for sure in about 2 days from this point...

...hi frosty!
hats off to your devotion!
xbox will be 100% with the perfection of vga support
...i'm from china, and desperately looking for such a vga cable!
...i have been trying to contact you through pm, but no luck...
...maybe it's that we are too far away from each other so you won't make me one
can you please tell me how to contact your cables' manufacturer? is it in GuangDong province or in other regions?
maybe they could send me a sample and i could help test it too!
...and i definitely will buy one with the final design! so you have got at least one foreign customer already
ps: there's a forum of xbox fans here in China, i cannot post the url but
people there are discussing about your realses too!
i'm sure some of them will want a ready-made xbox 1 vga cable too.
maybe when your cable is done designing, i can write a test report on your cable and see what people there thinks.
pps: should you sell them in China, and need any advise on chinese version of user's guide book, i'd be very happy to help, no fees
thanks again and please keep us posted on the new progesses!

This post has been edited by redpacman: Feb 25 2008, 12:03 PM