RS-232 has no dependency on any higher level protocol, however it does have a simple layer 1 (physical layer) set of standards which must be followed. The UART is the peripheral on the microcontroller which can send and receive serial data asynchronously, while RS-232 is a signalling standard. It is important to distinguish the difference between the terms UART and RS-232. In this lesson, we will learn a bit about the theory behind UART and RS-232, learn how to write a simple UART driver for the MSP430, and create a menu which gives the user the ability to change the frequency of the blinking LED during runtime. These days most PCs not longer have a serial port, so it is more commonly seen implemented using USB, however the concept is the same. The debug console is a serial interface which historically is implemented as RS-232 to connect with a PC serial port. When a board arrives in the hands of the software/firmware team, the first step is typically to get the debug console functional. One of the most common interfaces used in embedded systems is the universal asynchronous receiver/transmitter (UART).
It could be to transferring data to another device, sending and receiving commands, or simply for debugging purposes. An embedded system often requires a means for communicating with the external world for a number of possible reasons.
