250 likes | 704 Views
Introduction to VGA. Wei Miao Yuxuan Zhou. VGA. VGA = Video Graphics Array Introduced by IBM in 1987, still using today All points addressable Transmitting analog signal. XGA (Extended Graphics Array) UVGA(Ultra Video Graphics Array) HVGA(Half-size VGA) QVGA(Quarter VGA )
E N D
Introduction to VGA Wei Miao Yuxuan Zhou
VGA • VGA = Video Graphics Array • Introduced by IBM in 1987, still using today • All points addressable • Transmitting analog signal
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)
VGA Specifications • 256 kB Video RAM • 16-color and 256-color paletted display modes. • 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 (Usually 60 Hz) • Vertical blank interrupt • Planar mode: up to 16 colors (4-bit planes) • Packed-pixel mode: 256 colors (Mode 13h)
Pin 1 RED Red video • Pin 2 GREEN Green video • Pin 3 BLUE Blue video • Pin 4 ID2/RES formerly Monitor ID bit 2, reserved since E-DDC • Pin 5 GND Ground (HSync) • Pin 6 RED_RTN Red return • Pin 7 GREEN_RTN Green return • Pin 8 BLUE_RTN Blue return • Pin 9 KEY/PWR formerly key, now +5V DC • Pin 10 GND Ground (VSync, DDC) • Pin 11 ID0/RES formerly Monitor ID bit 0, reserved since E-DDC • Pin 12 ID1/SDA formerly Monitor ID bit 1, I²C data since DDC2 • Pin 13 HSync Horizontal sync • Pin 14 VSync Vertical sync • Pin 15 ID3/SCL formerly Monitor ID bit 3, I²C clock since DDC2
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.
. • 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
The VGA color palette • Contain 256 colors, choose from 218 colors. can arbitrary change the palette input (0,63,0) (0,0,63) (63,0,0)