Display architecture having variable data width

Abstract

A display architecture is disclosed which supports a variable, selectable number of bits per chip and a variable, selectable segment width. The architecture comprises a plurality of dynamic memory chips and a function generator. Each of the memory chips includes at least two data islands wherein each data island has its own data in/out line, chip select and increment bit supplied by the function generator. The function generator receives a starting address X.sub.o, Y.sub.o, the data path width N.sub.D and an encoded segment width S. A bit incrementer in the function generator generates increment bits A.sub.I based on the externally supplied modulo N.sub.D. The function generator generates the physical word address w.sub.o and physical bit address b.sub.o based on the starting address X.sub.o, Y.sub.o, the data path width N.sub.D and the encoded segment width S. Logic circuitry is provided which is responsive to an overflow bit produced by the bit incrementer to control spill and wrap functions. Spill results from the usual bit address incrementing where the data spills from the highest order chip to the lowest. Wrap is a special case when spill occurs at the right hand edge of the screen and data wraps around on the same scan line to the left hand edge of the screen.