Chapter 2 - PIC18F Microcontroller Series

Abstract

Microchip Inc. has developed the PIC18 series of microcontrollers for use in high-pin-count, high-density, and complex applications. The PIC18F microcontrollers offer cost-efficient solutions for general-purpose applications written in C that use a real-time operating system and require a complex communication protocol stack such as TCP/IP, CAN, USB, or ZigBee. PIC18F devices provide flash program memory in sizes from 8 to 128Kbytes and data memory from 256 to 4Kbytes, operating in a range of 2.0 to 5.0 volts, at speeds from DC to 40 MHz. The phase-locked loop circuit is new to the PIC18F series and provides the option of multiplying up the oscillator frequency to speed up the overall operation. The watchdog timer can be used to force a restart of the microcontroller in the event of a program crash. The in-circuit debugger is useful during program development and can be used to return diagnostic data, including the register values, as the microcontroller is executing a program. The input–output ports are located at the right side of the diagram. The PIC18F452 has five parallel ports named PORTA, PORTB, PORTC, PORTD, and PORTE. Most port pins have multiple functions such as PORTA pins can be used as parallel inputs-outputs, or analog inputs, and PORTB pins can be used as parallel inputs-outputs, or as interrupt inputs.