EGA-VGA adapter

From: Chuck McManis <cmcmanis_at_mcmanis.com>
Date: Sun Feb 11 12:07:05 2001

At 12:33 AM 2/11/01 -0800, Mike Ford wrote:
>A friend of mine sent me this message, but I really don't have a clue about
>EGA "intensity" or how to wire the adapter. Suggestions?
>
>I believe I'm making an EGA-VGA adapter.
>
>I found the pinouts on http://www.monitorworld.com/faq_pages/q17_page.html
>The problem I find is that VGA is analogue and EGA is/was TTL based (digital)

This is exactly right. TTL vs analog. Most multisyncs will do the EGA scan
frequencies. You should be able to create a circuit that looks something like:
            |\
     R -----+ >-------\/\/\--+----- Red out
          | |/ R1 |
          | |
          | +-----+ |
          +-+ | |
            | AND +---\/\/\--+
Intensity -+ | R2
            +-----+

And repeat it for each color. (intensity is common to all of them) This way
you get three colors from each 'gun' with The following truth table:

Red Int Output
  0 0 off
  0 1 off
  1 0 1/2 output
  1 1 1 full output

Note you will need to power this circuit.
--Chuck
Received on Sun Feb 11 2001 - 12:07:05 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:33:44 BST