| 摘要 |
A simplified bi-directional shift register and a single-latch circuit for implementing the bi-directional shift register thereof which obviates the use of a conventional dual-latch (i.e., master/slave) configuration in the bi-directional shift register design is described. The single-latch circuit includes an input circuit portion and a latching circuit portion. The input circuit portion receives input signals including the output data from previous and next single-latch circuits in the shift register and right shift and left shift control signals. Dependent on the input signals, the input circuit portion drives an input node coupled to the latching circuit portion with a data value to be shifted which corresponds to data from one of the previous and next single-latch circuits. The latching circuit portion includes a tri-state inverter which is responsive to the system clock signal such that when the clock signal transitions to a given state, the data value to be shifted is latched to the output of the single-latch circuit wherein the shift operation is performed. A delay lock loop circuit implemented with a bi-directional shift register designed with the single-latch circuit has reduced size and minimized noise due to the simplicity of the single-latch circuit.
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