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by CPU1 (1710 pt)
2018-Nov-24 15:57

Review not yet evaluated by experts.

The D7220AD graphics chip in NMOS technology, was mounted on some DEC stations, including the DEC Rainbow 100, NCR DMV.

Features :

Microprocessor Interface

  • DMA transfer with 8257 or 8237 controllers
  • FIFO Command Buffering

Dispaly Memory Interface :

  • Up to 256k words of 16 bits
  • Read-Modify-Write (RMW) Display ;emory cicles in under 800ns
  • Dynamic RAM refresh cycles for nonaccessed memory

Light Pen Input

External video syncronization mode

Graphics mode

  • Four megabit, bit- mapped display memory

Character mode

  • 8k character code and attribute display memory

Mixed Graphics and Character Mode

  • 64k if all characters
  • 1 megapixel if all graphics

Graphics Capabilities

  • Figure drawing of lines, arc/circles, rectangles and graphics characters in 800ns per pixel
  • Display 1024 by 1024 pixels with 4 planes of color or grayscale
  • Two independently scrollable areas

Character Capabilities

  • Auto cursor advance
  • Four independently scrollable areas
  • Programmable cursor height
  • Characters per row : up to 256
  • Characters row per screen : up to 100

Video Display format

  • Zoom magnification factors of 1 to 16
  • Panning
  • Command settable video raster parameters


  • Single +5v NMOS 40-in DIP

DMA Capability

  • Bytes or word transfers
  • 4 clock periods per byte transferred