Patents Examined by Eward P. Westin
  • Patent number: 5563528
    Abstract: A multiplexer for a programmable logic device (PLD) includes a control line decode circuit that substantially reduces the number of control lines necessary to program a multiplexer. Each multiplexer input line is programmably connected to at least three output lines to increase the number of routing options. A TTL buffer circuit located at the output of the multiplexer provides the user with various output signal options, whereas a word line driver coupled to the TTL buffer circuit increases signal drive. Local feedback signals are provided to the multiplexer to increase PLD functionality. Signals from the I/O pads are routed directly to the multiplexer rather than the UIM, thereby improving PLD speed. Moreover, using the multiplexer minimizes the number of input lines because the UIM is still available for routing connections. Therefore, the present invention provides both fast cycle time and fast multiple level logic.
    Type: Grant
    Filed: May 2, 1995
    Date of Patent: October 8, 1996
    Assignee: XILINX, Inc.
    Inventors: Sholeh Diba, Joshua M. Silver