摘要 |
A register using a single pin to provide two or more control signals (e.g., clock and data signals). The present invention decodes a three state input waveform to generate a clock/write signal and uses a three state clock waveform to generate a clock/read data signal. The present invention generally comprises a three-level receiver, a latch and an output driver to form a one-pin bidirectional interface used with a shift register. To write, the interface converts a three-level input signal into separate clock and data signals which drive the shift register. To read, the interface converts a bi-level input signal into a three-level output signal representing the output of the shift register. As a result, the present invention allows the programming of a device such as an erasable programmable read only memory (EPROM) in a clock chip while utilizing the fewest number of pins.
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