USING VMODE TO CHANGE DISPLAY MODES AND SCAN RATES The Tseng VGA provides you with the capability to utilize extended column modes with text applications. This means that your Tseng VGA 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 Tseng VGA 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 install VMODE.COM for the first time type VMODE INSTALL and then press ENTER. VMODE will display the following: Display Type: 1. VGA display 2. Variable-frequency display Which type of display are you using? Press F1 after you have made your selection, or press to quit. 3. 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. SELECTING DISPLAY SCAN RATES Vmode includes commands 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 modes. The following are available via the VMODE command. You may wish to add to your autoexec.bat file the Vmode command and parameter for the best display possible on your monitor. 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 * 48K 29,2A,30 72.7Hz 48KHz 800x600 * 45M 37,38 87Hz 35.5KHz 1024x768 interlaced * 65M 37,38 60.5Hz 49.0KHz 1024x768 non-interlaced * 72M 37,38 69.8Hz 56.3KHz 1024x768 non-interlaced * 72H 11,12,25,2E 72.7Hz 38.7KHz 640x480 * 1280-I 3F 87Hz 48.1KHz 1280x1024 interlaced * 1280-60 3F 60Hz 64.4KHz 1280x1024 * 1280-70 3F 70Hz 75KHz 1280x1024 * * Note: Not all modes are supported by all monitors. Attempting to use modes which your monitor does not support will produce unsatisfactory results. 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 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 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.