Interfacing PIC Microcontrollers

9

Serial Communication

Serial communication only requires one signal connection, so the total number

of hardware connections in a data link can be reduced to two or three, includ-

ing ground. A synchronous link may have a clock signal alongside the data, for

timing the transfer; an asynchronous one does not. This simplifies the wiring

where there are numerous peripheral devices for the MCU to communicate

with, or the connection is long distance. Within the microcontroller domain,

we tend to use the simpler forms of serial communications; the three PIC

16F877 serial interfaces described here are the USART, SPI (Serial Peripheral

Interface) and I

2

C (Inter-Inte ...