The circuit can be divided into two units: the controller unit and the display unit. The controller unit consists of a microcontroller circuit. The microcontroller used here is AT89C51 . The display unit consists of a seven segment circuit which is interfaced to the microcontroller. The circuit is similar to the seven segment circuit
with the only difference that here we have ten input pins. Each input pin corresponds to one of the digits to be displayed on the seven segment. Here the pin 0 to pin 7 of port P3, pin 6 and pin 7 of port P 1 are made the input pins. The output is sent to the seven segment through Port 2 of the microcontroller.