View tc74hc165p datasheet:

TC74HC165P IL00 C-MOS SERIAL-OR PARALLEL-INPUT SHIFT REGISTER —TOP VIEW— 10 SI S/ IN 1 VDD 16 L 11 A CK1 IN 2 15 CK2 IN 12 B 13 C E IN 3 14 D IN 14 D 3 E F IN 4 13 C IN 4 F 5 G G IN 5 12 B IN 6 9 SI : SERIAL DATA IN H QH 7 A-H : PARALLEL DATA IN 2 QH CK1 H IN 6 11 A IN CK1, CK2 : CLOCK IN ( ) 15 CK2 S/ : SHIFT/LOAD IN L OUT 7 10 SI IN QH 1 QH : 8th BIT OUT QH S/ L (COMPLEMENTALY) 8 GND 9 QH OUT INPUTS CONTENTS OUTPUT OPERATION S/L CK1+CK2 SI A----------H QA QB----- QH 0 x x a----------h a b----- h PARALLEL LOAD 1 0 x 0 QAo--- QGo RIGHT SHIFT 1 1 x 1 QAo--- QGo 1 x x QAo QBo--- QHo 1 0 x x QAo QBo--- QHo NO COUNT 1 1 x x QAo QBo--- QHo 0 : LOW LEVEL 1 : HIGH LEVEL x : DON’T CARE a-h : L