Write some Software

SELECTION OF MICROCONTROLLER: As we know that there so many types of micro controller families that are available in the market. Those are 1) 8051 Family 2) AVR microcontroller Family 3) PIC microcontroller Family 4) ARM Family Basic 8051 family is enough for our application; hence we are not concentrating on higher end controller families. In order to fulfill our application basic that is AT89C51 controller is enough. But still we selected AT89S52 controller because of inbuilt ISP (in system programmer) option. There are minimum six requirements for proper operation of microcontroller. Those are: 1) power supply section 2) pull-ups for ports (it is must for PORT0) 3) Reset circuit 4) Crystal circuit 5) ISP circuit (for program dumping) 6) EA/VPP pin is connected to Vcc. PORT0 is open collector that’s why we are using pull-up resistor which makes PORT0 as an I/O port. Reset circuit is used to reset the microcontroller. Crystal circuit is used for the microcontroller for timing pluses. In this project we are not using external memory that’s why EA/VPP pin in the microcontroller is connected to Vcc that indicates internal memory is used for this application.