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Keyboard and display interface adapter architecture

  • US 4,398,265 A
  • Filed: 09/15/1980
  • Issued: 08/09/1983
  • Est. Priority Date: 09/15/1980
  • Status: Expired due to Term
First Claim
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1. Interface adapter circuitry coupled to a plurality of input signals to a display having a plurality of display elements and further coupled to a self-clocking serial data bus having binary first and second forward data signal lines for receiving a binary data signal including data, address and control portions, transmitted from a signal source, the first and second forward data signals transmitted respectively on the first and second forward data signal lines having a first binary state before and after the data signal, the first forward data signal having a second binary state and the second forward data signal having the first binary state for data signal bits having a binary one state, the first forward data signal having the first binary state and the second forward data signal having the second binary state for data signal bits having a binary zero state, and the first and second forward data signals having the second binary state between successive data signal bits, said interface adapter circuitry comprising:

  • generating means coupled to the first and second forward data signal lines and being responsive to either the second binary state of the first forward data signal and first binary state of the second forward data signal, or responsive to the first binary state of the first forward data signal and the second binary state of the second forward data signal, for generating a clock signal;

    latch means for storing and providing an output signal and being coupled to the first and second forward data signal lines for storing and providing a binary one state of the output signal in response to the second binary state of the first forward data signal and the first binary state of the second forward data signal, and storing and providing a binary zero state of the output signal in response to the first binary state of the first forward data signal and the second binary state of the second forward data signal;

    receiving register means coupled to the latch means and the clock signal generating means and being responsive to the clock signal for serially receiving the latch means output signal, said received output signals being the binary data signal;

    decoding means coupled to the receiving register means for decoding a predetermined address signal in the address portion of the binary data signal in the receiving register means and generating a chip select signal when the predetermined address signal is decoded; and

    control means coupled to the decoding means and the receiving register means and being responsive to the chip select signal and the control signal portion of the binary data signal in the receiving register means for generating at least a first or a second control signal;

    control register means coupled to the receiving register means and control means and being responsive to the first control signal for receiving the data portion of the binary data signal in the receiving register means, said received data portion including output signals for selecting a predetermined sequence of display elements;

    display register means coupled to the receiving register means and control means and being responsive to the second control signal for receiving the data portion of the data signal in the receiving register means, said received data portion including output signals for the display; and

    means coupled to the control register means and display register means for applying the display register output signals to the display elements in response to a predetermined one of the control register output signals.

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