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VMODE.DOC
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1991-04-26
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VMODE - USING THE EXTENDED-COLUMN MODES
The VGA/16 provides you with the capability to utilize extended column
modes with text applications. This means that your VGA/16 board, when
interfaced with appropriate color displays, can produce 132x44,
132x28, 132x25, 100x40, and 80x60 modes in addition to the standard
80x25 and 40x25 modes. With the appropriate software, the 132-column
display capability allows emulation of terminals that require 132
columns of text.
With the VGA/16 board, you can switch back and forth between the 80-
column display modes and the various extended-column display modes. To
use VMODE, follow these steps:
1. First, be sure that the VMODE.COM utility is present on the disk
you are using.
2. To switch to a different mode, type the mode you wish to use and
then press ENTER:
Type
VMODE 25 - to switch to 132x25 mode
VMODE 28 - to switch to 132x28 mode
VMODE 44 - to switch to 132x44 mode
VMODE 40 - to switch to 40x25 mode
VMODE 60 - to switch to 80x60 mode*
VMODE 80 - to switch to 80x25 mode
VMODE 100 - to switch to 100x40 mode*
* Note: Not all modes are supported by all monitors. Attempting to use
modes which your monitor does not support will produce unsatisfactory
results.
Three additional modes are provided to enable you to change the scan
line resolution. This is to accommodate some software that
specifically looks for a particular number of scan lines. The 400 scan
line mode provides the most pleasing text resolution.
VMODE 200 - to provide 200 scan lines in 40- or 80x25 text modes.
VMODE 350 - to provide 350 scan lines in 40- or 80x25 text modes.
VMODE 400 - to provide 400 scan lines in 40- or 80x25 text modes.
VMODE SCAN RATES
Additional modes are available to provide additional scan rates that
may improve synchronization with a variety of monitors. Normally, the
default scan rates are effective, but some monitors may require
different scan rates for the most satisfactory display results. By
setting these modes, frequencies are adjusted that affect displayed
graphic modes. The following modes are available via the VMODE
command.
example: VMODE x
VMODE Modes Vertical Horizontal
x Value affected Refresh Rate Frequency Resolution
35K 29,2A,30 56Hz 35KHz 800x600
38K 29,2A,30 60Hz 38KHz 800x600
45M 37i,38i 86.5Hz 35.5KHz 1024x768 interlaced
65M 37n,38n 60.5Hz 49KHz 1024x76 non-
interlaced
72HZ Modes
The following graphic (not text) modes can be displayed after setting
the display the vertical refresh rate to 72HZ. The 72HZ mode will
provide a clearer display with less flicker on some monitors. Set the
VMODE parameter to VMODE 72HZ. After this is done you can use VMODE to
set the display to any of the graphic modes listed below.
VMODE Vertical Horizontal
x Value Refresh Rate Frequency Resolution
11 [72HZ] 72.70Hz 38.70KHz 640x480*
12 [72HZ] 72.70Hz 38.70KHz 640x480*
25 [72HZ] 72.70Hz 38.70KHz 640x480*
**2E [72HZ] 72.70Hz 38.70KHz 640x480*
* monitor must be capable of 72.70Hz vertical and 38.70KHz horizontal
frequency.
72MHz Modes
The following graphic (not text) modes can be displayed after setting
the display the video clock speeds to 72MHz. The 72MHz mode will
provide a clearer display with less flicker on some monitors. Set the
VMODE parameter to VMODE 72m. After this is done you can use VMODE to
set the display to any of the graphic modes listed below.
VMODE Vertical Horizontal Video
x Value Refresh Rate Frequency Clock Resolution
**37 [72m] 69.80 56.30 72.000 1024x768
***38 [72m] 69.80 56.30 72.000 1024x768
* monitor must be capable of 70Hz vertical and 56.3KHz horizontal
frequency.
** requires minimum of 512kb display memory; *** requires minimum of
1MB display memory.
Typing VMODE ? will display the full array of mode possibilities.
Users that are familiar with the characteristics of their monitors
will find these modes more useful.
NOTE: Choose modes/resolutions that are compatible with your video
board configuration and monitor capabilities.
USING THE COMPATIBILITY MODES
Some programs are written to be run using specific modes or are
written according to particular video standards. For example, there
are programs that require a monochrome adapter or those that are
written exclusively for a Color Graphics Adapter. When these kinds of
programs are used, it becomes necessary to make your VGA/16 board
appear to be what the program requires. This is easily accomplished.
In order to select a mode that will change the "appearance" of the
video adapter to the software, you need only select the appropriate
VMODE parameter. When another mode is needed or desired, you can
simply select the mode using another VMODE parameter. In order to
return to the default mode (VGA), type VMODE VGA or power down (the
VGA mode will be in effect upon power-up). The following is a list of
modes and their uses. A complete listing of available modes can be
seen by typing VMODE ?.
VMODE CGA - To set the adapter for compatibility with the Color
Graphics Adapter.
VMODE MDA - To set the adapter for compatibility with the
Monochrome Display Adapter.
VMODE HERCULES -To set the adapter for compatibility with the Hercules
card.
VMODE EGA - To set the adapter for compatibility with the Enhanced
Graphics Adapter.
VMODE VGA - To set the adapter for compatibility with the Video
Graphics Array.
A typical use might be for using game software that requires CGA
resolution. Using VMODE CGA will put the VGA/16 board in CGA mode. If
the software needs to be booted in order to work, you simply place the
VGA in CGA-compatible mode with VMODE CGA, and warm-boot with your
game diskette in the A: drive.
You may switch modes in this manner as often as you wish. VMODE ? will
display a list of the available modes. Entering VMODE with no
parameter will display a menu screen from which to choose a text mode.