How do I determine pinout of integrated vga header?

[ltm0807]

I m pretty much lost when it comes to this stuff, but I am trying to attach a standard DB15 monitor to an older 1U piece of equipment that wasn t really designed to have a monitor attached to it (if it makes a difference, it s an old, out of service Cisco CE560 that I am trying to convert into a Linux server). It does have an integrated video card and I found a 16 pin header on the mother board that appears to be video out. Using what I found here: http://pinouts.ru/Video/VGA15_pinout.shtml , I was able to find the R, G, and B knowing that they are all 75ohms, and I found these on pins 1, 4, and 7 of this header. My problem, however, is that I am a little unsure how to figure out what I should look for to try to trace down the rest of the pins on this header. What pins are "essential" for basic VGA output, and how can I track them down? I realize that I am going to need HSYNC and VSYNC for sure, but how can I tell which pins that they are on? Any help would be greatly appreciated!

[cyberquip]

Sounds like you need to experiment.... looking at fig 1.1, this unit has a standard composite output. http://www.cisco.com/univercd/cc/td/doc/product/webscale/content/ce500hig/11199ov1.htm#xtocid75143





Depending on the monitor, there are several variables involved in going from standard composite to RGB ..some of which is more trouble than worthed--especially on older equipment... here s a good bit of general info


http://www.tkk.fi/Misc/Electronics/faq/vga2rgb/index.html





Good luck

[ltm0807]

So, you have identified the RGB signals, that is a good beginning.


Then, check out which pins in the header that are grounded, that is probably several ones as it is common practice to have a separate ground pin for each of the RGB signals. It is easy to do by resistance measurements.





To figure out which pins are used for H and V sync, it is best to check with an oscilloscope. At the same time, check out the signal levels. In some cases, it might be TTL or CMOS levels, in other cases, it might be 0,3 or 1,0 V p-p.





Other pins in the header might be "monitor ID pins" according to old IBM VGA standard, or an I2C bus according to modern VESA standard (DDC).

[moma1817]

Vtech,





Thank you for your assistance. Good find from the Cisco site, I never even noticed that due to the fact that I don t have the AV model. I m sure the motherboard is probably identical however. I didn t even consider that this may not be a VGA header, but instead be composite video. Rather than try to output this to a monitor, would it be easier to just dump it onto a television? If so, what else do I need to track down in order to make it work since I don t have the handy front panel composite connector for my content engine? Thanks!

[chinaflights]

torbjorn,





Thank you! That is a very helpful guide to get started with. I don t have an oscilloscope available, unfortunately, so I ll see if I can match based off of the signal levels you mentioned.

Vtech,





Thank you for your assistance. Good find from the Cisco site, I never even noticed that due to the fact that I don t have the AV model. I m sure the motherboard is probably identical however. I didn t even consider that this may not be a VGA header, but instead be composite video. Rather than try to output this to a monitor, would it be easier to just dump it onto a television? If so, what else do I need to track down in order to make it work since I don t have the handy front panel composite connector for my content engine? Thanks!

[maheshkashyap21]

Unfortunately, my CE does not have this adapter (I believe it is only included on the AV models, which I do not have). All I have is the 16-pin block on the motherboard.





Would researching the video controller on the motherboard help me at all in regard to determining for sure what this is? I did a basic google search, but didn t come up with anything solid. If it helps at all, the chip has the following info on it:

[chucky68]

Is this just a lost cause?

[chinaflights]

Ok, thought it had the connector





I would not call it a lost cause yet. 69000 series was actually rather advanced in it s time and reading it s application notes should give you ideas---made by Asiliant technologies.





http://www.asiliant.com/69000.htm

[KaylaRodriguez5]

vtech,





Once again, very nice find. You seem to know how to find all the good stuff . I ll dig through all of that and see what I can come up with, looks like it may take me some time though. Thanks again!