Description: This program demonstrates a half-duplex 9600-baud UART using
// Timer_A3 using no XTAL and an external resistor for DCO ROSC. DCO used for
// TACLK UART baud generation. The program will wait in LPM4, echoing back
// a received character using 8N1 protocol. On valid RX character, the
// character is echoed back.
// Using a 100k resistor on ROSC, with default DCO setting, set DCOCLK ~ 2MHz.
// ACLK = n/a, MCLK = SMCLK ~2MHz DCOCLK
