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Author Topic: Howto Vga Using Internal Sync Signals  (Read 135 times)

Risca

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Howto Vga Using Internal Sync Signals
« on: April 24, 2005, 04:13:00 AM »
Please tell us how it went running progressive mode. uhh.gif

I'm quite curious. I'm thinking of doing this mod myself, I only has to get my hands on a xbox with a conexant chip  biggrin.gif

Well, I just got a datasheet for the focus encoder in my mail, so a focus chip would do too biggrin.gif

BTW, the H-sync and V-sync are the same on focus as on the conexant.
H-sync == Pin 35
V-sync == Pin 36

Enjoy!
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unixxx

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Howto Vga Using Internal Sync Signals
« Reply #1 on: May 22, 2005, 12:03:00 PM »
I just completed this mod a couple of days ago but as most are reporting neither of the monitors I tried seem to be syncing properly with the internal sync signals; I just get a blank black screen.  I'll post if I get one to work.
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unixxx

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Howto Vga Using Internal Sync Signals
« Reply #2 on: May 22, 2005, 04:11:00 PM »
Did you guys configure the dashboard or use a modified BIOS when you did this mod?  Right now I've got the dashboard set to support all HD modes, have the HD cable ID configured, and am testing it while an HD game is playing.  The Xbox believes a cable is connected because it doesn't complain about there not being one.  Not that I'm extremely experienced with video circuitry, but does anybody find it odd that the buffer in the internal VGA mod inverts the sync signals?  Thanx.
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TB_88

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Howto Vga Using Internal Sync Signals
« Reply #3 on: June 19, 2005, 07:33:00 PM »
BUMP, this topic needs a solution...
Think about this! Pure VGA with MS bios ! biggrin.gif
I noticed this would be kinda hard for noobisch people lik me, so I would like to see another solution.

What happened with the other sync seperator chips? Any news, I saw that one guy said it would also give you a good sync without need of a hacked bios. And just as easy to build like the known sync seperator circuit...
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The Zep Man

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Howto Vga Using Internal Sync Signals
« Reply #4 on: June 19, 2005, 10:34:00 PM »
My first comment is: Good job on the progress. Keep it going. beerchug.gif

However, my second comment: Why so much trouble? There is already a circuit available that works under HDTV-mode, eliminating the need for a VGA-BIOS.

For the people who like the original VGA-circuit more (a LM1881 eliminates the need for a SOG-monitor): iND-5003-VGA from JunkMonkey is a nice VGA-BIOS with a lot of features. Or take the new VGA-patch for NKPatcher10, for the softmodders. If you mod your original cable to not use 101 (1+3, VGA)-mode, but to use 110 (2+3, HDTV-mode), you can even get HDTV-resolutions on a standard monitor.

Also, doesn't this solution with the sync-signals also require a VGA-BIOS? blink.gif unixxx, do you want to get PBL Metoo and iND-5003-VGA from the usual places and check it out with a cable with mode 101 (1+3, VGA)? Maybe you'll get other (useful?) signals. ohmy.gif
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TB_88

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Howto Vga Using Internal Sync Signals
« Reply #5 on: June 20, 2005, 04:22:00 PM »
Is there a sync chip out there wich can get the sync from a HD signal and enable you to get a normal vga signal in good color?
If there is, it must be the easiets way to go.
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TB_88

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Howto Vga Using Internal Sync Signals
« Reply #6 on: June 20, 2005, 04:28:00 PM »
I just found this on this page: http://www.tkk.fi/Mi...vgamonitor.html
QUOTE
How to connect sync-on-green RGB signal to VGA monitor ?
Sync separation is a process is needed ot get the sync signals out of green picture line. The sync format included in green line has the same format as composite sync, so the LM1881 based circuit described above can be used for this process when it is connected to green line.

The R and B lines can go directly to the monitor. The green line contains normal R signal plus sync signals. To make it exactly normal R signal, those sync signal needs to be removed from R signal. I don't have any good circuit designs to give for that remove the sync signals from R line. You might try to survive without any conversion in R line by just connecting it to the R input in monitor. This direct connection (with sync still in R monitor) should not harm anything in the monitor. Some monitors will show everyhting nicely picture wven though it has those syncs added. Some other monitors have problems in showinbg the colors correctly if they are fed with green signal with syncs (the balance of green picture component gets wrong).

NOTE: Before starting any special building projecss check if your monitor can also handle sync on green green directly. Some monitors can do that (check your monitor technica data for information on this). In this case you need only to connect R, G and B lines directly to monitor.



If we can remove the sync signal from the G line we wouldn't need a VGA bios, right? I mean after G line have gone through the sync seperator.
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TB_88

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Howto Vga Using Internal Sync Signals
« Reply #7 on: June 20, 2005, 04:56:00 PM »
QUOTE
However, my second comment: Why so much trouble? There is already a circuit available that works under HDTV-mode, eliminating the need for a VGA-BIOS.

What, wait!? There is? Point me there...
Why isn't it where the other tut's are then?
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Jameson42

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Howto Vga Using Internal Sync Signals
« Reply #8 on: July 02, 2005, 11:01:00 PM »
There is a transcoder circuit out there to go from YPbPr to VGA, designed by ken gaspar a while back... works well for 480p and 720p I've heard.  No need for a vga-bios.  Look here for the schematics... a couple posts down on the page.
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JaredC01

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Howto Vga Using Internal Sync Signals
« Reply #9 on: September 12, 2005, 10:03:00 PM »
QUOTE(sandman1687 @ Sep 12 2005, 10:42 PM)
if someone gets their hands on the MAX4383, then we could test this shit out.
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yaywoop

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Howto Vga Using Internal Sync Signals
« Reply #10 on: August 19, 2007, 10:36:00 PM »
QUOTE(unixxx @ Sep 14 2005, 07:37 AM) View Post

Apparently if you use the internal sync signals you don't need a VGA BIOS; that's why I was trying to get this hack to work.  Read through all of this section: http://www.xbox-linu...al_sync_signals  Especially the last line.

The Zep Man - I'm just playing with hardware right now.  I want to get this working without any software modifications so I can play it on Live.


did you actually read the VGA Howto?
the xbox doesn't put out vga signals without a modified bios. even if you get the sync from inside, you still will have component video coming out of the AV port.
the only way to play xbox on a vga monitor and use Live is to get a transcoder or a xbox 360!

anyway the reason i am posting on such an old thread; did anyone get this working? will a monitor sync to only 1.5V?

btw i am using frostythesnowman's vga patch with an X2 bios. works great, can even do 1080i in NTSC mode
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yaywoop

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Howto Vga Using Internal Sync Signals
« Reply #11 on: August 26, 2007, 12:55:00 AM »
w00t. i finally got around to making this VGA sync buffer. i ran the 74HC14 off the 3.2V line with a normal diode to get the voltage down to about 2.9V (which works with a 1.5V input signal i found) i wired it all up and ran some wires outside the xbox to a connector. switch my modchip to the VGA bios and it worked!
i am getting some lines of slightly shifted pixels running down the screen but its ok for playing games
so there you go. this mod does actually work when you have the right bios (and a game with progressive video output)
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