包旅上思 Parallel outputs A3 Ax Clear D D CLK S1 4×1 4×1 4×1 4×1 So MUX MUX MUX MUX 3210 3210 3210 3210 Serial Serial input for input for shift-right shift-left 2 Parallel inputs Fig.6-7 4-Bit Universal Shift Register 2002 Prentice Hall,Inc. M.Morris Mano DIGITAL DESIGN,3e