Information for VGA to TV driver version 0.6
Written by Tomi Engdahl 27 October 1996

This program is a driver for VGA to TV circuit designed by Tomi 
Engdahl. You are allowed to use this program freely for your
own noncommercial applications. You can also freely copy
this driver packet to you friends, but you are not allowed
to ask any money for that. For commercial applications
ask more detaild from the author Tomi Engdahl (tomi.engdahl@iki.fi).

There is no guarantee that this program works anyway as desired.
I take no responsibility of the problems this program might cause.

Instructions for use

VGA to TV driver is a small (less than 2 kilobytes) DOS TSR program 
which enables VGA card to be connected to ordinary NTSC or PAL TV with 
VGA to TV converter designed by Tomi Engdahl. 

The driver program replaces some VGA BIOS routines with
it's own code to make VGA card to use frequencies suitable to PAL TV set.
The program is designed to be only used with my circuit which is
connected to TV. Do not keep your VGA monitor connected to VGA card
when the driver is loaded, because the frequencies the driver use
can damage some monitors !

The program is very easy to use. Just run the driver program 
(VGA2PAL.COM for PAL TVs or VGA2NTSC.COM for NTSC TVs) and your 
VGA card is in TV mode. 

When you have loaded the driver to memory the only way to get rid of 
the driver normally is to reboot the computer. The driver works also 
nicely in Windows 3.1 and Windows 95 full-screen dos sessions.
If you run this program under Windows, you can have the normal
Windows in VGA frequencies and the full screen DOS session
in TV frequencies. 

The driver program supports following VGA modes:

Mode    Resolution                      Comments
-----------------------------------------------------------------
00H     40x25 text                      Uses half of screen width
01H     40x25 color text                Uses half of screen width
02H     80x25 text                      Uses 8x8 font
03H     80x25 color text                Uses 8x8 font
04H     320x200 graphics 4 color
05H     320x200 graphics 4
06H     640x200 graphics 2
0DH     320x200 graphics 16 color
0EH     640x200 graphics 16 color
0FH     640x350 graphics 2
10H     640x350 graphics 4 color
11H     640x350 graphics 16 color
12H     640x480 graphics 16 color
13H     320x200 graphics 256 color
95H     640x480 grpahics 2560 color     Cirrus specific mode

VGA2TV.COM is a small (less than 2 kbytes) TSR program which loads to
memory and stays there until you restart your computer.


Contacting the author of the program

I am interrested in hearing comment how well this program works
with different platforms. You can reach my at my e-mail address
at tomi.engdahl@iki.fi. When you report how well this driver works,
include the following information to the message (without full
information set the information is nearly useless).

- version number of the driver used
- brand and model of you VGA card
- computer type
- DOS version used
- what drivers are loaded in memory
- programs used with the driver and how well they worked

If there is something wrong in some modes, then tell also
following information:

- the screen mode where the problem is
- exact description (very technical preferred) what is wrong

Remember to post infomation about the newest drivers only.
If your driver is older than few months, then get a newest versio
from http://www.iki.fi/~then/circuits/vga2tv.html and test it
before reporting about problems.

History

Version 0.1
- only test version, did not do anything useful
Version 0.2  16 June 1996
- supports VGA mode 03h and 13h at PAL frequencies
Version 0.3
- added support for text modes 02h and 03h, but font looks agly
- added support for 640x480,256 graphics using Cirrus cards
- automatic switch to TV mode when driver is loaded
Version 0.4
- font problems in text mode solved
Version 0.5   3 October 1996
- Added support for all normal VGA modes (except B&W specific)
Version 0.6   27 October 1996
- interrupt calling routine rewritten for better compatibility
- added check if driver already installed
- driver supports now both PAL and NTSC

