Shenzhen Brother Young Development Co., Ltd.

vga cable cables

vga cable cables
Product Detailed

VGA Cable
1.Male to male,15pins
2.Top quality goods & excellent service
3.ROHS compliant
4.price is favorable

 VGA Cable specifications

256 KB Video RAM (The very first cards could be ordered with 64KB or 128KB of RAM at the cost of losing some video modes). 16-color and 256-color modes 262,144-value color palette (six bits each for red, green, and blue) Selectable 25.175 MHz or 28.322 MHz master clock Maximum of 800 horizontal pixels Maximum of 600 lines Refresh rates at up to 70 Hz Vertical blank interrupt (Not all clone cards support this.) Planar mode: up to 16 colors (4 bit planes) Packed-pixel mode: 256 colors (Mode 13h) Hardware smooth scrolling support Some "Raster Ops" support Barrel shifter Split screen support 0.7 V peak-to-peak 75 ohm double-terminated impedance (18.7mA – 13 mW)

The VGA supports both All Points Addressable graphics modes, and alphanumeric text modes. Standard graphics modes are:

640×480 in 16 colors 640×350 in 16 colors 320×200 in 16 colors 320×200 in 256 colors (Mode 13h)

As well as the standard modes, VGA can be configured to emulate many of the modes of its predecessors (EGA, CGA, and MDA). Compatibility is almost full at BIOS level, but even at register level, a very high value of compatibility is reached. VGA is not compatible with the special IBM PCjr or HGC video modes.

 Signal

The intended value for the horizontal frequency of VGA is exactly double the value used in the NTSC-M video system. The formula for the VGA horizontal frequency is thus (60 ÷ 1001) × 525 kHz = 4500 ÷ 143 kHz ≈ 31.4686 kHz. All other frequencies used by the VGA card are derived from this value by integer multiplication or division. Since the exactness of quartz oscillators is limited, real cards will have slightly higher or lower frequency. For most common VGA mode 640×480 "60 Hz" non-interlaced the horizontal timings are:

Parameter

Value

Unit

Pixel clock frequency

25.175

MHz

Horizontal pixels

640

 

Horizontal sync polarity

Negative

 

Total time for each line

31.77

µs

Front porch (A)

0.94

µs

Sync pulse length (B)

3.77

µs

Back porch (C)

1.89

µs

Active video (D)

25.17

µs

(Total horizontal sync time 6.60 µs)

 

The vertical timings are:

Parameter

Value

Unit

Vertical lines

480

 

Vertical sync polarity

Negative

 

Vertical frequency

59.94

Hz

Front porch (E)

0.35

ms

Sync pulse length (F)

0.06

ms

Back porch (G)

1.02

ms

Active video (H)

15.25

ms

(Total vertical sync time 1.43 ms)

640 × 400 @ 70 Hz is video mode used for booting most x86 personal computers.[7]

640 × 480 @ 60 Hz is the default MS-Windows graphics mode with 16 colors.[7]

The actual timings vary slightly. For example for 640×480 @ 60fps a 25,17 µs active video time with a pixel frequency of 25,174 MHz gives 633 pixels rather than the expected 640 pixels.



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