msp430F149,说明：回声一个接收到的字符，RX ISR使用。在主循环UART0准备接收一个字符中断活跃。主循环等待LPM3。UART0的ISR部队主循环后退出LPM3接收回波接收到的字符一个字符。-Descr iption: Echo a received character, RX ISR used. In the Mainloop UART0 is made ready to receive one character with interrupt active. The Mainloop waits in LPM3. The UART0 ISR forces the Mainloop to exit LPM3 after receiving one character which echo s back the received character.