Here is a simple circuitry which will help you to understand how will you interface and LED with a micro-controller. The code is written to turn on and off the LED after some short delay, this is one of the beginning circuit when one tries to gain some hands on the micro-controller interfacing. This circuit help beginners to learn through the micro-controller course which we will provide you by exploring you some of the introductory circuit with the micro-controller. It is the best approach to get started with the Atmel family of Micro-controllers, because they are easy to understand and does not contain too much complexities.
in this circuit we are using AT89C2051 micro-controller and just an LED. The other components like resistor,capacitors and crystal are the prototype configuration with the micro-controller and used in almost every configuration of the Micro-controller.

For circuit diagram and the coding click the link given below:

Download attachment