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Hello friends, I hope you all are doing great and having fun with your lives. In today's tutorial, I am going to elaborate the shift register, 74HC165. It's an amazing Parallel In Serial Out Shift register, which is capable of increasing the input pins of your microcontroller. It can be interfaced with almost all kinds of microcontrollers like Arduino, PIC Microcontroller, Atmel Microcontroller etc.

You should also have a look at Arduino 74HC165 Interfacing: Increase Input Pins and should also download its Proteus Simulation. It will help you to better understand this shift register. Now let's have a look at its pinout:


Basics of 74HC165

  • 74HC595 is a shift register which works on PArallel In and Serial OUT Protocol.
  • It has 8 input pins where you can connect different sensors etc. and then it has 1 Serial Output Pin, which should be connected to the Microcontroller.
  • With the help of Clock Pin, we can receive all these parallel 8 inputs serially from a single output into the microcontroller.
  • We can also connect multiple 74HC165 in parallel to increase the input pins.
  • Let's say if I have connected 3 shift registers in parallel then the input pins will increase by 8 x 3 = 24.
  • So, we can control 24 digital sensors by a single Arduino Pin.
  • Let's have a look at  the 74HC595 Pinout:

74HC165 Pinout

I have explained the 74HC165 Pinout in detail below:

  • Pin A, B, C, D, E, F, G and H are input pins for sensors. These are all digital Pins.
  • Pin CLK INH is the clock enable.
  • Pin CLK is the clock.
  • Pin SER is the serial Pin from where we will connect our Microcontroller.
  • Pin # 8 should be connected to ground.
  • Pin # 16 is Vcc which should be +5V.

74HC165 Applications

It has a lot of applications in daily life. We have a lot of applications where we have to connect multiple sensors such as hotel management systems, home automation systems, bank security systems etc. In such applications, we can easily use the 74HC165 shift register to acquire data from all these sensors through a single Pin.


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