VGA: Video Graphics Array

Introduction

For the PS/2 range of PCs, IBM launched VGA in 1987. The first graphics card with the ability to display up to 16 colors at 640 x 480 screen resolution was the original VGA chipset. VGA could display up to 256 colors even at a reduced resolution of 320 x 200 pixels, which made it simpler to represent lowercase letters.

Other manufacturers quickly followed with graphics cards that could display thousands to millions of colors, but they were all supersets of VGA. Since VGA is supported by all PCs, all of these graphic cards had the same foundation.

• For example, the Windows operating system from Microsoft Corporation loaded its recognizable splash screen in VGA color.

What is VGA?

A Video Graphics Array is the full name for VGA. The VGA standard was initially created by IBM. With a 640 x 480 resolution display, 16 colours at once, and a 60 Hz refresh rate, it employs analogue signals. A maximum of 256 colours can be seen at once from the 262, 144 colour series. It has a 6-Bit Digital to Analog transformer that converts analogue RCB (red, green, and blue) signals.

Hardware Design

One chip (the RAMDAC) contained both a digital-to-analog converter (DAC) and the color palette random access memory (RAM), and VGA only needed extra video RAM and timing crystals since the cathode-ray tube controller (CRTC) was integrated into a primary VGA chip which eliminating numerous more chips from earlier graphics adapters.

In contrast to earlier IBM PC versions, PC/XT, PC, and PC AT, which needed a separate display adapter put in a slot to connect a monitor, this low part count allowed IBM to include VGA right on the PS/2 motherboard. The use of the word "array" rather than "adapter" in the name suggested that the expansion device was a single part that could be integrated into a system as opposed to being a completely independent device.

Capabilities

Standard graphics modes

• 16-color or monochrome at 640x480

• 256 colors and 320x200 (Mode 13h)

• With 4 or 16 colors, 320 x 200 (CGA compatibility)

• 16-color or monochrome resolutions of 640x350 or 640x200 (EGA compatibility)

Standard text modes

• 80 x 43 or 80 x 50, produced with an 8 x 8 pixel font grid, is 640 x 344 or 640 x 400 pixels, respectively.

• 40 x 25, rendered with a 9 x 16 pixel font, is 360 x 400.

• 720 x 400, the effective resolution of 80 x 25, rendered with a 9 x 16 pixel font.

Technical Details

Typical uses of selected modes

The need for such a low-quality, universally compatible fallback has diminished since the turn of the millennium as VGA-signalling-standard panels or adaptors incapable of showing anything beyond the original resolutions have become more scarce.

Signal timings

The original standard value for the horizontal frequency of the 640 x 480 mode of VGA is exactly double that of the NTSC-M video system since it was much simpler to offer optional TV-out options or external VGA-to-TV converter boxes at the time when VGA was developed. Additionally, compared to CGA, which also supports composite monitors, it is at least twice as expensive.

Connector

One kind of computer port is the VGA (Video Graphics Array/Video Graphics Adapter) connector, which is used to connect peripheral devices for sending video signals as an output. Color display panels with 640 x 480 resolution, 60 Hz refresh rate and 16 colors displayed at once are provided by a VGA connector.

Color Palette

Register-based palettes are used to translate the 18-bit output gamut of the VGA color system to colors with various bit levels. It is backward compatible with the EGA and CGA adapters despite enabling more bit depth for the palette in these modes.

The 36-bit RGB value stored in each palette register selects a color from the DAC's 18- bit color space.

Use

Many programmers used such a configuration, with the monochrome card displaying debugging data and the other card running a program in graphics mode and it was commonly used to concurrently display graphics from a Lotus 1-2-3 spreadsheet on a low-resolution CGA monitor and high-resolution text on a monochrome display.

Hardware Manufacturers

• SiS

• Matrox − MAGIC RGB

• Plantronics: Colorplus

• NEC

• IIT

• Tamarack

• Realtek

• Oak Technology

• LSI

• Chips and Technologies

Successors

Extended Graphics Array (XGA)

IBM introduced the XGA display standard in 1990. Later, it replaced 1024 x 768 as the most used moniker for the display resolution.

Super VGA (SVGA)

In 1988, the development of SVGA was spearheaded by NEC and other VESA members including ATI Technologies and Western Digital. SVGA graphics display resolutions up to 800 x 600 pixels, while VGA graphics have a maximum resolution of 640 x 480 pixels.

Conclusion

In this article, we discussed The first graphics card with the ability to display up to 16 colors at 640 x 480 screen resolution was the original VGA chipset. VGA could display up to 256 colors even at a reduced resolution of 320 x 200 pixels and as well as we learned about their uses and technical details.

FAQs

Q1. Can VGA support audio?

Ans: The incoming HDMI signal would be ignored because VGA does not carry an audio stream.

Q2. Are there different kinds of VGA cables?

Ans: The 14-pin and 15-pin VGA cables come in two different varieties. In the majority of applications, 14-pin cables will function, however, 15-pin cables could be necessary for wider display compatibility. Specifically, this is a 15-pin VGA cable.

Q3. Can you use a computer without a VGA cable?

Ans: You can, indeed. That is how my system is set up. The HDMI cable and power cord are included in the box. Not included is VGA.