Problems with UART on MSP430F6721

I am using a MSP430F6721 for the first time and having problems with the
UART (A0). I am using a 32KHz crystal on XT1. I look at the clock on PJ.3
and it is at 32KHz. I use ACLK for the baudrate clock and have a baudrate of
9600. I set UCA0BR0 to 0x3. I try and transmit a byte and find that the bit
width is 92uS rather than 104uS. I find I cannot write to the MCTL register.
It is always 0x0000. According to the user guide the UCBRF is all zeros and
UCBRSx is 0x3. I am using IAR assembler. In the user guide it says there are
3 bits for UCBRSx. In the Assembler it shows a register named UCA0MCTLW and
UCBRSx has 8 bits. (plus 4 for UCBRFx and UCOS16). I am modifying all
registers while UCWRST =1. It seems, to me, that the user guide does not
match the IAR program. I have not had problems with other MCUs I have used
which are similar.

 

Any thoughts as to what I am doing wrong?

 

Thanks

 

Peter