MSP430 USART setup

In the 23x0 family, anytime an rx break is detected, the UART stops receiving bytes until it's reset/unreset. This is described in errata USCI16. Code to reset the UART anytime a break has been detected:

lastStatus = UCA0STAT;
b = UCA0RXBUF;
if (lastStatus & UCBRK) {
// bug in TI hardware: break shuts down UART, so restart it
	UCA0CTL1 |= UCSWRST;
	UCA0CTL1 &= ~UCSWRST;
	}
handleRxByte(b);

See also:

• http://mspgcc.sourceforge.net/baudrate.html Baudrate Calculator+
• http://www.msp430.info/modules.php?name=Sections&op=viewarticle&artid=2 "Using and setting up the UART modulation register" In low power / low clock frequency applications, the TX and RX modulation values might be different.++
• http://www.elo.utfsm.cl/~lsb/elo311/labs/msp/MSP430_Praktikum/Assembler/projects/Project_7_(UART_RS232)/uart02_19200.s43 Assembly code that cal's RC based DCO via 32K xtal to get 19.2k baud RX w TX echo.++

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