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Many serial-port communications are between embedded systems or between

embedded systems and PCs. This chapter shows how to program serial commu-

nications for an embedded system’s microcontroller. The code examples are for

Microchip Technology’s PIC18F4520, with each example provided for both

microEngineering Labs, Inc.’s PICBASIC PRO compiler and Microchip’s

MPLAB C18 C compiler. The concepts and much of the code are portable to

other chip architectures and compilers.

 


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Microchip’s PIC microcontrollers are inexpensive, widely available, and include

variants to suit a range of applications. Many of the chips have hardware sup-

port for asynchronous serial communications.

Other microcontrollers support serial ports as well. The details vary, but sup-

port typically consists of a hardware UART or USART with a series of registers

to configure the port, monitor events, and store received data and data to send.