VGA to SCART adapter boards

[mkl]

Self made Vga to Scart RGB adapters for TV-frequency VGA-signal (vga card needs to ouput 15625Hz/50(25i)Hz.
At least 4 pcs of version "008", first in this series. (slightly different "009" pcb ordered)
20€ /pce
optional 24c02 or 24c01 eeprom 1€
optional 3.5mm stereo plug cable for sound 1€
shipping 3€ untracked

Male hd-15 vga (can use female-male cable to video output if +5v connected)
Can be connected directly to vga output, but it puts heavy weight on the connector on mainboard or video card.
Scart socket (v008 cuts them a little to fit on pcb). 3.5mm stereo phono jack for connecting cable to sound card/mainboard phono jack.
Linux can take advantage of EDID eeprom for 15kHz television signal while booting, except grub/boot loader screen (Windows probably doesn't understand television modes directly.)
Has voltage doubler to select 4:3, and the other signal is driven to select the scart rgb input on television.
Doesn't have protection to shutdown bad frequencies to television.
74HCT86D circuit makes scart synch pulses regardless of vga sync polarities, as Tomi Engdahl circuit on ePanorama.net

 

[Archimedes]

Interested but I'd like to know more about it ?
Link ? Doc ? Thanks.
Sorry me if I've missed sthing somewhere.

 

[mkl]

There is no information page on www for this board, at least not yet.
This adapter follows many other vga to scart adapter circuits found on the web, but adds an EDID eeprom socket and voltage doubler in order to make one of the input selection signals on scart interface.
Schematic should show many details.

- - - Updated - - -

I have used and modified some code from Linux source to make edid-files.
I will post the codes sometime
Notes;
-Intel integrated graphics didn't support pixel clock under 25MHz, so 1440x resolution on edid was used (one other manufacturer support 720x pixel clocks)
-Intel xrandr can be used to show 720x (or 704x, or..) on >25MHz clocks by somekind of compression on chip.

 

[Echolalia]

Could i use this to connect rgb consoles to a vga monitor?

 

[Archimedes]

Technical informations about video signals is great.
Now I'd prefer to read : this machine will work perfectly with my adaptor in screen modes a b c and not d ; this console will perfectly work, that one not etc ...
unless you want to sell only to techie guys of course ;-)

 

[mkl]

Could i use this to connect rgb consoles to a vga monitor?

No, because sync signal direction is from VGA to SCART. Also, a VGA monitor needs higher frequencies.
Many VGA outputs can output television frequencies, 50 Hz 15625Hz , "625-line / 50 field (25 frame) per second (576i)"

- - - Updated - - -

Technical informations about video signals is great.
Now I'd prefer to read : this machine will work perfectly with my adaptor in screen modes a b c and not d ; this console will perfectly work, that one not etc ...
unless you want to sell only to techie guys of course ;-)

I have mainly experimented on laptop and desktop PC:s with integrated graphics, using mostly Linux.
Intel D945GCLF2 mini itx board, AMD (radeon) laptop,

 

[Archimedes]

Interest withdrawn.

 

[mkl]

It may be difficult and frustrating to get television frequencies set-ups running. Windows and/or graphics card drivers for Windows may sabotage attempts to drive displays at 15kHZ/50Hz.
PowerStrip software is for creating custom resolutions. But it might not work on your display card, such as a chipset integrated display controller.
Found this thread related to WinUAE: http://eab.abime.net/showthread.php?t=69278 which mentions soft15khz, but the site which was linked was down,
searching Soft15khz.exe found http://forum.arcadecontrols.com/index.php?topic=66402.2280
On a few years back 64-bit Debian installation, it was needed to disable the automatic scanning of connected monitors with TV-frequency edid on the adapter board, because it made the system freeze periodically for a moment, unlike with vga monitors. The "modelines" for TV were then set up by command line tools and init scripts.