17-04-2014, 04:23 PM
4 bit SHIFT REGISTER
SHIFT REGISTER.doc (Size: 75.5 KB / Downloads: 9)
DESCRIPATION:-
A shift register is an n-bit register with provision for shifting its stored data by one position at each clock pulse. The logical configuration of a shift register consists of a chain of flip-flops connected in cascade, with the output of one flip-flop connected to the input of the next flip-flop. All flip-flops receive a common clock pulse which causes the shift from one stage to the next. Fig. 1 shows a simple shift register configuration. The new bit to be shifted into one end must be specified, and the bit shifted off the other end is lost unless it is saved externally. Although Fig. 1 shows a right-shift register, the same register can obviously be used for left shifts simply by reversing the sense of the bits. Most shift registers have provision for shifting only in one direction, but some have a control input that allows either left or right shifting to be specified at each clock.