A MOS cursive-character generator

Abstract

Cursive characters can be made to be more readable, more attractive, and better suited to the operation of graphic CRT terminals than the usual dot-matrix type; a system using cursive-type characters achieves much higher writing rate while requiring much less bandwidth than that using dot-matrix-type characters. This paper presents an economical method of generating the x, y, and z analog signals for forming cursive characters with the deflection system of a CRT. A circuit design embodying a complete 48-stroke character generator on a single MOS integrated circuit is described. The IC accepts 7-bit ASCII code and outputs x, y, and z analog signals to generate any one of 32 standard ASCII characters in 5 μs. Additional groups of 32 characters can be added by merely paralleling additional chips. The entire 32 character digital and analog function has been implemented on a single self-contained 16-pin silicon-gate MOS chip 125 X 165 mil in size. Character encoding on the chip is accomplished in one mask at the diffusion step, and a straightforward mask-generation procedure has been developed.