Basic 8051 Microcontroller Circuit

February 1, 2011 — 2 Comments

To use microcontroller in your project you need basic circuit to make use of all functions of 8051 microcontroller.

Below diagarm shows the basic circuit of 8051 microntroller:

Parts needed for basic circuit 8051 microcontroller:

  • 8051 Microcontroller (AT89c51 / AT89c52 / AT89s51 / AT9s52) – 1
  • IC7805 – +5 V (IC 7805 – voltage regulator) – 1
  • 12MHz Oscillator – 1
  • 30pF capacitor – 2
  • 10uF capacitor -1
  • 8.2k resistor -1
  • 0-12V Transformer with bridge circuit to convert 12V AC to DC. (input to IC7805)

Make bridge circuit (using 4 diodes) – full wave rectifier circuit to convert AC to DC . Give DC input to IC7805 circuit(Refer powersupply circuit). Give 5V to Pin 40(VCC), Pin 30(EA), Pin 9(reset) of microcontroller. Connect oscillator between pin 18 and 19. Make pin 20 as ground.

To test your basic circuit, write small LED blink program using Port 1 KEIL software . Simulate program and compile it get the HEX code and burn into controller.

Don’t worry guys there will be separate posts for burning and writing codes for your chip.  So don worry about last two lines of  this post 🙂



2 responses to Basic 8051 Microcontroller Circuit

  1. how capacitor works in dc current n what is the role of resistor at pin 9 of microcontroller…

    • When the circuit is power up, the capacitor will start to charge at a rate determined by the R*C constant. This will provide a voltage at the reset pin that will exponentially decay from 5 to 0 V, causing the reset (high-to-low transition) happen some time after the power up of the 8051, ensuring a realible start up.

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