uart test code

uart-pi.c

#include <msp430.h>
#include <legacymsp430.h>

// https://github.com/wendlers/msp430-harduart/blob/master/src/uart.c
// https://github.com/ideasium/msp430-uart/blob/master/msp430-uart/uart.c
// http://www.geom.uiuc.edu/~huberty/math5337/groupe/digits.html

char *pi = "3.141592653589793238462643383279502884197169399375105820974944592307816406286";
int   pos = 0;

void transmit_char() {
	UCA0TXBUF = pi[pos];
	pos++;
	if (pi[pos] == '\0') pos = 0;
}

interrupt(USCIAB0TX_VECTOR) uart_transmit_isr() {
	P1OUT ^= BIT6 | BIT0;
	transmit_char();
}

int main() {
	WDTCTL = WDTPW + WDTHOLD;

	// configure clocks
	DCOCTL  =  CALDCO_16MHZ;
	BCSCTL1 =  CALBC1_16MHZ;

	// i/o
	P1DIR = BIT6 | BIT0;
	P1OUT =  0x00;

	P1SEL |= BIT1 | BIT2;
	P1SEL2 |= BIT1 | BIT2;

	// initialise usci
	UCA0CTL1 |= UCSSEL_2;   // hold reset, set smclk
	UCA0BR0  =  0x82;
	UCA0BR1  =  0x06;
	UCA0MCTL =  UCBRS2 | UCBRS1;

	UCA0CTL1 &= ~(UCSWRST);

	IE2      |= UCA0TXIE;

	__enable_interrupt();

	transmit_char();


	for (;;) {}
	return 0;
}