Today in this tutorial i'll explain you how to control 74HC165 parallel in serial out(PISO) shift register using your ARDUINO board.Here we used 74HC165 for increasing numbers of inputs of your ARDUINO board.Shift registers are often used for the purpose of saving pins on a microcontroller. Every microcontroller has a limited number of pins for general inputs and outputs (GPIO).Some time we have required more inputs and our controller does not provide such a inputs at that time parallel in serial out(PISO) shift register is used to increase inputs.
An 8 bit shift register needs 4 lines of a microcontroller. One pin to clock for data transfer,one for clock enable,one for shifting/loading/latching the bits,and one for serial data transfer.Here we used only 3 pins of microcontroller. One pin for loading the bits,one pin to clock for data transfer,one pin to serial data transfer.In 74HC165 Clock enable pin is active low so we connect it to ground.Two 74HC165 can be cascaded to increase lots of inputs.
