The purpose of this article is to explain how to interface a PIC microcontroller to a PC via the USB port.Although the concepts are universal, the examples are specifically for use with MikroElektronika’s ‘MikroC Pro for PIC’. PIC18F2550 and PIC18f4550 are famous for their USB Module. To stay ahead you can start with their datasheets.The most difficult part of this project is exactly what is required to get the PIC microcontroller to communicate with the USB port. The two most important things that absolutely have to be correct are the microcontroller configuration, and the USB device descriptor. If even the smallest thing is incorrect about either of these, communication will not occur.