PIC18F4550 is an 8-bit microcontroller manufactured by Microchip with nano-Watt technology with enhanced flash, USB, and high-performance. It is a 40-pin microcontroller that comes with several features such as memory endurance, self-programmability, extended instruction set, enhanced CCP module, and addressable USART and 10-bit ADC (Analog to digital converter).

The 18F4550 has 32K of flash, 12 MIPs from a 48MHz external crystal (internal PLL up to 48MHz), and a hardware Full Speed USB 2.0 peripheral. That's right, this little guy can communicate directly with USB. Package can be programmed in circuit and even has a dedicated ICD port on the TQFP versions.

It consists of 4 timers or an external oscillator is interfaced for clocking purposes, 13 channels for ADC, ADC comparators, and other peripherals. It is an 8-bit popular microcontroller available in various packages like QPF, QPN, and DIP. It is selected based on the type of project and requirement.

It is very simple to program the PIC18F4550 controller and easy to interface with many peripheral devices using 35 programmable I/O pins. With the feature of the USB interface, it provides hassle-free communication between the controller and the PC. The watchdog timer can be reset to use the systems without any human interface.