VGA Introduction

VGA Introduction

What is VGA interface?

VGA full name is Video Graphics Array, is a video transmission standard introduced by IBM in 1987 along with the PS/2 machine, with the advantages of high resolution, fast display rate, rich colors, etc., and has been widely used in the field of color displays.

The VGA standard is very outdated for today's personal computer market. Even so, VGA is still a standard that is supported by the largest number of manufacturers, and PCs must support it before they can load their own unique drivers.

The VGA interface is a special interface for computers that use the VGA standard to output data. 15 pins in total, divided into 3 rows of 5 holes each, the VGA interface is the most widely used type of interface on graphics cards, and most graphics cards come with this interface. It transmits RGB analog signals as well as synchronization signals (horizontal and vertical signals).

VGA interface pin definition and the connection

The VGA interface has a total of 15 pins, and its corresponding pin interface is defined as below.

1. Red base color red (pink line)

2. green base color green (light green line)

3. blue base color blue (light blue line)

4. Address code ID Bit (also part of the RES, or for ID2 display labeled bit 2)

5. Self-test ( different definitions of each family ) ( generally GND ) ( black line )

6. Red GND ( 4, 6, 7, 8, 11 for the shield line, connected together )

7.Green GND

8.Blue GND

9.Reserved ( different definition for each) (yellow line)

10. Digital GND (red line)

11. Address code (ID0 display marked bit 0)

12. Address code (ID1 display mark bit 1) (green line)

13. Line synchronization (white line)

14. Field synchronization (brown line)

15. Address code ( ID3 or display mark bit 3 ) ( orange line )

The basic principle of VGA imaging

The chipset converts the image (detection) signals stored in digital format in the graphics memory into R, G, B analog signals, and line and field synchronization signals via DAC, and then outputs them to the display device for imaging.

The display is scanned by means of a raster. The electron beam on the display screen is scanned regularly from left to right and from top to bottom. In the scanning process, controlled by the line synchronization signal, sweeping to the right point by point, the inverse of the time to complete a line scan is called line frequency. At the same time will return to the left end of the screen within the pulse of the line synchronization cycle, controlled by the field synchronization signal, scanning from top to bottom to complete a detection signal, the reciprocal of the completion of this detection signal cycle is called the field frequency. Finally, through the combination of different pixels to form the display image.

Advantages of VGA

Although VGA was proposed in 1987 and has been developed for many years, it still plays a role in various industries and has many unique advantages of its own.

(1) VGA has the advantages of high resolution, fast display rate and rich color.

(2) VGA display system also has the advantages of low cost, simple structure and flexible application.

(3) VGA display outputs RGB three primary colors signal, RGB color mode is a color standard in the industry. It is through the red (R), green (G), blue (B) three color channel changes and their superposition to each other to get a variety of colors, is widely used.

VGA shortages

VGA is an analog signal and can only transmit video signals and does not support audio transmission.

VGA does not support hot-plugging.

In VGA specification, the maximum VGA signal cable is 15 meters. This is because VGA transmits analog video signal, which is easy to be interfered, when the signal transmission distance is more than 15 meters, the quality of VGA signal will be seriously degraded. the CRT monitor is working in analog signal state, which is very easy to be interfered, when the speaker and other magnetic things are placed next to the monitor, the monitor will appear ripple for this reason.

VGA applications

At present, VGA can be widely used in public places such as supermarkets, stations and airports for propaganda and prompt information display, as well as in factory workshops for operation information display in the production process.

HornmicLink also has the ability to provide you with high quality VGA cables and VGA converters.

By HornmicLink_Henry @230324 20:38