VGA card information

VGA frequencies in different modes

From: [email protected] (Stephen Quigg)
Newsgroups: sci.electronics
Subject: Re: VGA startup board/monitor sync?
Date: 14 May 91 23:06:07 GMT
Organization: CSIRO Maths and Stats & Applied Physics, Sydney, Australia
The VGA board tells the monitor what to expect by the polarity of the horiz. and vert. sync signals. Here's what an NEC MultiSync 2A sets up to.
Vert Res.      Horiz Freq    H Sync    Vert Freq    V Sync
                            Polarity               Polarity

350 lines      31.5 kHz      pos       70.07 Hz     neg
400 lines      31.5 kHz      neg       70.07 Hz     pos
480 lines      31.5 kHz      neg       59.95 Hz     neg
600 lines      35.2 kHz      pos       56.24 Hz     pos
Your problem is probably one of the following; 1. You are trying a mode your monitor won't support. 2. Your monitor is out of adjustment. 3. Your monitor is faulty. Possibly, the card or monitor is not "playing the rules", eg monitor expects one set of sync rates according to the sync polarities, and the card is sending out another (unlikely but...)

VGA monitor ID signals

From: [email protected]
Newsgroups: sci.electronics
Subject: Re: VGA monitors
Date: 22 May 91 01:49:05 GMT
Organization: The Portal System (TM)
Mike Diack asked about VGA monitors.

Mike, I don't know if this is related to your problem or not, but IBM monitors have 3 pins dedicated to a "monitor ID" code, which is available to the VGA (or 8514/A or XGA) card, and also to the software. OS/2 uses it, for example, to automatically install the correct display support. The code:

PIN 4      PIN 11      PIN 12           Meaning
 n/c        n/c         n/c         No monitor attached
 n/c        n/c         GND         Mono monitor with no support for 1024x768
 n/c        GND         n/c         Color monitor with no support for 1024x768
 GND        GND         n/c         Color monitor with support for 1024x768
Maybe your projector is not providing the code to tell the VGA that it is there. If so, you can try modifying the plug.

DISCLAIMER: I know this works for some Sony monitors, which support 1024x768 but don't provide the proper code to the PS/2, so they come up in 640x480. By changing the plug, the system sees the monitor as high-res-capable, and configures itself for 1024x768. Whether grounding pins in your plug will your projector, however, I can't say (although I doubt it).

Good luck.

Jay Keller

VGA feature connector

From: [email protected] (Dominic H Goode)
Subject: VGA Feature Connector
Date: 12 Apr 93 22:59:42 GMT
Organization: Brunel University, Uxbridge, UK
X-Newsreader: TIN [version 1.1 PL8]
Does anyone know how the VGA video feature connector operates? I would like to know which of the pins are inputs, which are outputs, and which are bidirectional (if any - and how the direction is selected).

I have found a pinout for the connector:

Video Feature Connector Pinouts.

Pin     Name   Function
1       PD0    Dac Pixel data bit 0
2       PD1                   bit 1
3       PD2                   bit 2
4       PD3                       3
5       PD4                       4
6       PD5                       5
7       PD6                       6
8       PD7                       7
9       -      Dac Clock
10      -      Dac Blanking
11      -      Horizontal Sync
12      -      Vertical Sync
13      -      Ground

14      -      Ground
15      -      Ground
16      -      Ground
17      -      Select Internal Video
18      -      Select Internal Sync
19      -      Select Internal Dot Clock
20      -      Not Used
21      -      Ground
22      -      Ground
23      -      Ground
24      -      Ground
25      -      Not Used
26      -      Not Used
And I assume that pins 1 - 12 are outputs, and 17 - 19 are inputs. Is this correct?

The reason is this - I have a Rombo Media Pro+ video digitising card. It chroma keys its output into the vga monitor signal. However, although it is supposed to work with an ET-4000 with Hi-colour RAMDAC, the colours on screen behave as if the top 2 bits of colour information are missing, and red, green, blue signals are swapped around. Rombo has suggested that this may be due to insufficient buffering on the feature connector outputs, and is happy to sell me a buffer device for 50 pounds. I would rather save about 45 pounds, and build my own. I assume it would require (for example) a 74F244 buffer IC (or two).

Can anyone help? Any information on the feature connector would be highly appreciated!

Please could you reply by email :
[email protected]

VGA feature connector

component side

pin     function
1       PD0 (DAC pixel data bit 0)
2       PD1 (DAC pixel data bit 1)
3       PD2 (DAC pixel data bit 2)
4       PD3 (DAC pixel data bit 3)
5       PD4 (DAC pixel data bit 4)
6       PD5 (DAC pixel data bit 5)
7       PD6 (DAC pixel data bit 6)
8       PD7 (DAC pixel data bit 7)
9       DAC clock
10      DAC blanking
11      Ext. horizontal sync
12      Ext. vertical sync
13      Ground

back side

pin     function
1       Ground
2       Ground
3       Ground
4       Select Internal Video
5       Select Internal Syncs
6       Select Internal DAC
8..11   Ground

VESA DPMS monitor power management

VESA DPMS is a monitor power managament standard designed for green PC concept. VESA DPMS defines method how a screen saver program can put monitor to power save state when it blanks the screen. The signalling to monitor is handled using normal monitor sync signals: screen saver can turn one of sync signals (or both) off and the monitor knows from this that it must turn to power save mode.

VESA DPMS power states:

                NORMAL          STANDBY         SUSPENDED       OFF
H-sync          On              Off             On              Off
V-sync          On              On              Off             Off
Power level     100%            80%             <30W            <8W
Recovery time   N/A             ~1 sec          ~4 sec          ~8-20 sec

NUTEK monitor power management

NUTEK is a Swedish standard for monitor power management so that screen saver program can turn monitor to power save mode when computer is not used for a while. NUTEK works using the following pronciple: when the picture signa coming to the monitor has been totally black for lomg enough, the monitor turns to power save mode. When there is other than just black coming to monitor, then the monitor turns back to normal operation.

VESA modes

This list is not complete list of SuperVGA modes standardized by VESA. For complete documentation check VESA VBE standard.

        AX = 4F02h
        BX = mode
                bit 15 set means don't clear video memory
  Return: AL = 4Fh function supported
        AH = status
            00h successful
            01h failed
  SeeAlso: AX=4F01h,AX=4F03h

  Values for VESA video mode:
   00h-FFh OEM video modes (see AH=00h)
   100h 640x400x256
   101h 640x480x256
   102h 800x600x16
   103h 800x600x256
   104h 1024x768x16
   105h 1024x768x256
   106h 1280x1024x16
   107h 1280x1024x256
   108h 80x60 text
   109h 132x25 text
   10Ah 132x43 text
   10Bh 132x50 text
   10Ch 132x60 text
  ---VBE v1.2---
   10Dh 320x200x32K
   10Eh 320x200x64K
   10Fh 320x200x16M
   110h 640x480x32K
   111h 640x480x64K
   112h 640x480x16M
   113h 800x600x32K
   114h 800x600x64K
   115h 800x600x16M
   116h 1024x768x32K
   117h 1024x768x64K
   118h 1024x768x16M
   119h 1280x1024x32K
   11Ah 1280x1024x64K
   11Bh 1280x1024x16M
  Index:        video modes

  Values for S3 OEM video mode:
   201h 640x480x256
   202h 800x600x16
   203h 800x600x256
   204h 1024x768x16
   205h 1024x768x256
   206h 1280x960x16
   208h 1280x1024x16
   211h 640x480x64K (Diamond Stealth 24X)
   212h 640x480x16M (Diamond Stealth 24X)
   301h 640x480x32K