Patents Represented by Attorney Fancis I. Gray
  • Patent number: 4613856
    Abstract: An electrical circuit is described that requires a reduced number of data bits for character-address and video-mode information by using a predetermined bit combination of the video-mode information as part of the character-address information. Character-address and video-mode information is output from a random access memory (RAM) to a character read only memory (ROM) and a video-mode detection circuit that produces outputs to enable video-mode circuits in the video control circuitry. One output of the video-mode detection circuit is coupled to an address input of the character ROM that has characters divided into two character sets. A predetermined bit combination of the video-mode information produces an output from the video-mode detection circuit that selects one of the character sets while the other bit combinations produce an output from the detection circuit that selects the other character set.
    Type: Grant
    Filed: April 4, 1983
    Date of Patent: September 23, 1986
    Assignee: Tektronix, Inc.
    Inventors: Daniel C. Olin, Russell Y. Anderson, Steven C. DenBeste