Hi,
I am working with the MSP430F6438 and I am developing a UART which uses an external clock at 32kHz. I need my UART to be configured as follows:
1200 baud rate, 1 start bit, 8 data bits, 1 odd parity bit, 1 stop bit. The UART seems to communicate just fine if I am using an internal clock (UCA1CTL1 |= UCSSEL_2), however, when switching to UCSSEL_0 I am unable to transmit/receive anything. My code is posted below.
Any help is much appreciated,
Thanks,
Rafael
void UART_setup(void)
{
/* set XT1 oscillator XCAP to 6pF */
while(BAKCTL & LOCKIO) /* Unlock XT1 pins for operation */
BAKCTL &= ~(LOCKIO);
UCSCTL6 &= ~(XT1OFF); /* XT1 On */
UCSCTL6 |= XCAP_1; /* XCAP = 6pF */
do
{
UCSCTL7 &= ~(XT1LFOFFG + DCOFFG); /* Unlock XT1 pins for operation */
SFRIFG1 &= ~OFIFG; /* Clear fault flags */
}while (SFRIFG1&OFIFG); /* Test oscillator fault flag */
UCSCTL6 &= ~(XT1DRIVE_1); /* Enable XT1 */
P8SEL |= BIT2 + BIT3; /* P8 TX/RX select */
P8DIR |= BIT2 + BIT3; /* P8 TX/RX direction */
UCA1CTL1 = UCSWRST; /* **Put state machine in reset** */
UCA1CTL1 |= UCSSEL_0; /* External Clock */
UCA1CTL0 |= UCPEN; /* Parity enabled (odd) */
UCA1BR0 = 27; /* 32kHz 1200 (see User's Guide) */
UCA1BR1 = 0; /* 32kHz 1200 */
UCA1MCTL = UCBRS_2 + UCBRF_0 + UCBRF0; /* Modulating */
UCA1CTL1 &= ~UCSWRST; /* **Initialize USCI state machine** */
UCA1IE = UCRXIE|UCTXIE; /* Enable USCI_A1 TX/RX interrupt */
}
