The MSP430 hardware USART does not operate as expected 
as per the settings of the USART control registers.

The hardware USART module in the MSP430 is a state machine whose 
state has to be RESET every time a new USART configuration is 
defined. This can be achieved by a set/reset sequence of the SWRST 
bit in the UCTL register by firmware.

The SWRST bit is set by default on power on reset(POR). If the USART 
module parameters are defined for the first time by configuring 
the control registers after POR, configuring the UCTL register should 
be the last in the sequence such that the SWRST is reset to start 
the state machine with the defined settings. This can be achieved 
with a MOV.B #000X XXX0B,&UCTL in assembly language and UCTL = 0b000X XXX0 
in C language. Please refer the device User`s guide and code examples 
for more details.

If the USART module is re-configured in firmware then a set/reset 
sequence of the SWRST bit must be done after re-configuration, to 
re-start the USART state machine with the new configuration.