Introduction to VGA Wei Miao Yuxuan Zhou 1

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VGA VGA = Video Graphics Array Introduced by IBM in 1987, still using today All points addressable Transmitting analog signal 3

XGA (Extended Graphics Array) UVGA(Ultra Video Graphics Array) HVGA(Half-size VGA) QVGA(Quarter VGA) SVGA(Super Video Graphics Array) SXGA(Super Extended Graphics Array) SXGA+(Super Extended Graphics Array) WVGA(Wide VGA) 4

VGA Specifications 256 kB Video RAM 16-color and 256-color paletted display modes. Selectable MHz or MHz master clock Maximum of 800 horizontal pixels Maximum of 600 lines Refresh rates at up to 70 Hz (Usually 60 Hz) Vertical blank interrupt Planar mode: up to 16 colors (4-bit planes) Packed-pixel mode: 256 colors (Mode 13h) 5

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Pin 1REDRed video Pin 2GREENGreen video Pin 3BLUEBlue video Pin 4ID2/RESformerly Monitor ID bit 2, reserved since E-DDC Pin 5GNDGround (HSync) Pin 6RED_RTNRed return Pin 7GREEN_RTNGreen return Pin 8BLUE_RTNBlue return Pin 9KEY/PWRformerly key, now +5V DC Pin 10GNDGround (VSync, DDC) Pin 11ID0/RESformerly Monitor ID bit 0, reserved since E-DDC Pin 12ID1/SDAformerly Monitor ID bit 1, I²C data since DDC2 Pin 13HSyncHorizontal sync Pin 14VSyncVertical sync Pin 15ID3/SCLformerly Monitor ID bit 3, I²C clock since DDC2 7

front porch : the delay between the end of the video data of a scan line and initial edge of the sync pulse. pulse width :the period of time that the sync signal is asserted back porch : the delay between when the final edge of the sync pulse and the first piece of data for the next scan line. 8

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VGA Basic Components 10

. 11 Sequencer Graphics Controller Attribute Controller DAC CRT Controller

VGA Memory Organization Use only 16-bit addresses, but 256K ram VGA uses planar instead of linear memory organization Chain-4 Memory Organization Planar Memory Organization Odd/Even Memory Organization 12

The VGA color palette Contain 256 colors, choose from 2 18 colors. can arbitrary change the palette input 13 (63,0,0) (0,0,63) (0,63,0)

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Question? 15