Cathode ray tube controller

Abstract

A cathode-ray tube controller uses a content addressable associative storage array (10) to generate repetitively a sequence of video control signals for a CRT to which it is attached. A binary coded counter (4) incremented by the system clock (CL) of the CRT provides a sequence of binary count values representing the running count of the CRT clock. This running count is continuously available and applied as an input search argument to the associative array. A plurality of predetermined count values, derived with reference to the running count, are stored as binary coded words in selected rows of the associative array. The match signals generated on the sense lines of the array as the running count value becomes equal to the predetermined count values in the array provide the video control signals to control the various display functions of the CRT. One of the signals is used to re-set the running count value so that the sequence of signals is repeated at regular intervals. The timing of the video control signals is determined solely by the running count values entered into store. An input data register (15) is provided in order to load words into the array to define or to change the functions of display. A read register (17) is provided in which interrogated words are read for test and event timing purposes.