ADV476

a FEATURES Personal System/2* and VGA* Compatible Plug-in Replacement for INMOS 171/176 66 MHz Pipelined Operation Three 6-Bit D/A Converters 256؋18 Color Palette RAM RS-343A/RS-170 Compatible Outputs Blank on All Three Channels Standard MPU Interface Asynchronous Access to All Internal Registers ؉5 V CMOS Monolithic Construction Low Power Dissipation Standard 28-Pin, 0.6" DIP and 44-Pin PLCC APPLICATIONS High Resolution Color Graphics CAE/CAD/CAM Applications Image Processing Instrumentation Desktop Publishing AVAILABLE CLOCK RATES 66 MHz 50 MHz 35 MHz GENERAL DESCRIPTION CMOS Monolithic 256؋18 Color Palette RAM-DAC ADV476 FUNCTIONAL BLOCK DIAGRAM The ADV476 (ADV®) is a pin compatible and software compatible RAM-DAC designed specifically for VGA and Personal System/2 color graphics. The ADV476 is a complete analog output RAM-DAC on a single monolithic chip. The part contains a 256ϫ18 color lookup table, a pixel mask register as well as a triple 6-bit video D/A converter. The ADV476 is capable of simultaneously displaying up to 256 colors, from a total color palette of 262,144 addressable colors. The on-chip asynchronous MPU bus allows access to the color lookup table without affecting the input video data via the pixel port. The pixel read mask register provides a convenient way of altering the displayed colors without updating the color lookup table. The ADV476 is capable of generating RGB video output signals which are compatible with RS-343A and RS-170 video standards, ...