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8051 Pin Configuration

8051 Pin Configuration

Let’s get started. I assume you are already familiar with the concept of micro-controllers (specially the 8051) and have some rough idea about the internal architecture because I will avoid going into it. I will just stick to how-to-use tricks for the 8051. However, for the sake of brief introduction, let me highlight the important aspects of the 8051 microcontroller.

8051 Pin Configuratoin

Meet the original 8051. It has a total of 40 pins, including

  • 4 input/output ports ( each 8 bits or 1 byte )
  • Except PORT1, each port has some dual nature or functionality
  • RXD/TXD for serial transmission
  • Interrupts and Timers

The remaining PINS are for powering up the device. From now on, I will refer to the ports as P0, P1, P2 and P3. They all have 8 pins for data transfer so the individual pins are named as

  • P0.0 – P0.7
  • P1.0 – P1.7
  • P2.0 – P2.7
  • P3.0 – P3.7

You are supposed to get familiar with the PIN out diagram because you will need it every now and then. The more you practice, the better you will remember each PIN without even checking out the data sheet. And talking of its data sheet, here you go

PDF : AT89C51 Datasheet


Muhammad Faizan Khan is an Electrical Engineer and a Computer Geek. He is a technical guy and has more than 3 years of experience in Embedded Systems, Digital Logic Design, Computer Programming and everything else that’s logical. He mostly writes tutorials related to microcontrollers for beginners in his blog, PhaseWire.

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