Asynchronous serial communication can be added to an MSP430x11x（1） application by using
hardware features of the integrated timer_A3 module. This report provides several UART
function examples demonstrated with an RS232 interface between an MSP430F1121 Flash
MCU and a PC serial port （see Figure 1）。 A description of how to use timer_A3 hardware that
provides automatic start-bit detection， baud-rate generation， and data-bit latching is detailed.
Hardware features of timer_A3 greatly reduce software and CPU overhead typically associated
with microcontroller software UART implementations. Hardware features of timer_A3 also allow
the UART to operate as a background function simultaneously with other real-time system tasks.