What Is a VGA Driver?

VGA (Video Graphics Array) is a video transmission standard introduced by IBM with the PS / 2 machine in 1987. It has the advantages of high resolution, fast display rate, and rich colors. It has been widely used in the field of color displays. At present, the application of VGA technology is mainly based on computers, notebooks and other devices with VGA display cards. However, on some devices that require displaying high-resolution color images without using a computer, the application of VGA technology is rarely seen. This paper researches the implementation method of embedded VGA display. The embedded VGA display system based on this design method realizes the display and control of VGA images. The system has the advantages of low cost, simple structure, and flexible application. It can be widely used in advertising and prompt information display in public places such as supermarkets, stations, and airfields. Application in multimedia form

VGA mode

VGA (Video Graphics Array) is a computer display standard proposed by IBM in 1987 that uses analog signals. This standard is very outdated for today's personal computer market. Even so, VGA is still a low standard supported by most manufacturers. PCs must support the VGA standard before loading their own unique drivers. For example, the Microsoft Windows family of products

The specifications of VGA are as follows:

* 256 KiB of Video RAM

* 16-color and 256-color modes

* A total of 262144 colors (6 bits for each of red, green, and blue, a total of (26) 3 types)

* Selective 25.2 MHz or 28.3 MHz processing frequency

* Up to 720 horizontal pixels

* Up to 480 lines

* Up to 70 Hz update frequency

* Vertical Blanking interrupt (not supported by all cards)

* Flat mode: up to 16 colors (4 bit panel)

* Packed-pixel mode: 256 colors (Mode 13h)

* Ability to smoothly scroll animation faces

* Some "Raster Ops" support

* Barrel shifter

* Support split screen

VGA supports APA (All Points Addressable) mode that can control pixels individually, and also supports letter and number text mode. The standard graphics mode is as follows:

* 640 × 480 × 16 colors

* 640 × 350 × 16 colors

* 320 × 200 × 16 colors

* 320 × 200 × 256 colors (Mode 13h)

It also supports drawing the resolutions of previous specifications in an analog way: EGA, CGA, and MDA.

The standard VGA text mode uses a plane composed of 80 × 25 or 40 × 25 letters or numbers. Each character's blocky area can choose 16 kinds of foreground colors and 8 kinds of background colors; 8 kinds of background colors come from the lower bit capacity set (in today's standards, such as ffffff or 000000). The character itself can also be set to blink or not, and the blinking action of the character is all at the same time. The flashing function of the screen and the function of selecting the background color are interchangeable. In other words, only one of them can be selected. These options are the same as CGA converters previously produced by IBM.

Although VGA supports black and white and color text modes, black and white mode is rarely used. Most VGAs use color mode when displaying black and white mode, that is, drawing gray characters on a black background. Monochrome displays using VGA can also support such color modes well. If the modern monitor and graphics card are improperly connected, it will occasionally cause the VGA part of the graphics card to detect that the monitor is monochrome, which will cause the BIOS to display in black and white mode. Usually after loading the operating system and appropriate drivers, the settings of the graphics card are overwritten and the display will change back to color.

In colored text mode, each character is actually represented by two bytes. The lower byte is used to display characters, while the higher byte is used to represent attributes such as color, flicker, and so on. This pairwise byte mode has been passed down from CGA. The English full name of VGA is Video Graphic Array, that is, display graphics array. VGA supports simultaneous display of 16 colors or 256 gray levels at a higher resolution of 640X480, and simultaneous display of 256 colors at a resolution of 320X240.

The human eye is much more sensitive to color than resolution, so even lower resolution images are still vivid. VGA quickly became popular due to good performance. Manufacturers have expanded on the basis of VGA. For example, if the video memory is increased to 1M and it supports higher resolutions such as 800X600 or 1024X768, these extended modes are called VESA (Video Electronics Standards Association,

At present, most computers and external display devices are connected through an analog VGA interface. The digitally generated display image information inside the computer is converted into R, G, and B primary color signals and line, Field sync signal, the signal is transmitted to the display device through the cable. For analog display devices, such as analog

The main application is that the display resolution is set too high, the display is blank, and it cannot be displayed normally. To fix this problem, you must enable VGA mode, so the resolution and refresh rate will be very low, which is convenient for users to change to the appropriate settings.

Is a way to diagnose Windows systems.