Blinking LEDs in Sequence:
This is another basic introductory circuit of micrcontroller. In this circuit we turn on and off the leds in sequence bu using microcontroller AT89C2051, one LED is on at one time then after some delay it becomes off and another LED turns on and so on. There are two ways to do this sequence in assembly language. First way is to turn on one port and keep other ports off at one time then turn on second port and keep other ports off and so on. Second way to do it is by load the value 01111111(07FH in hexadecimal) to the register and then rotating the value in the register, every time after one rotation the rotated value is moved to the port 1.