#include <msp430.h>
#include <signal.h>

static volatile long count =0;

static inline void init_timer_A() {

    TACCR0 = 25000; // since clk = 1MHhz => 25us count
    TACTL = TASSEL1 | MC0;
    //TACCTL0 |= OUTMOD2; / Toggle mode - OUTMODx = 100
    TACCTL0 |= CCIE; //enable interrupt for capture/compatre;
}


static inline void uart_init() {
//config uart for 9600 bps
    P1SEL = BIT1 + BIT2;
    P1SEL2 = BIT1 + BIT2;

    UCA0CTL1 |= UCSSEL_2; //select UCSSELx = 10 - SMCLK
    UCA0BR0 = 104;
    UCA0BR1 = 0;
    UCA0MCTL = UCBRS0; //modulation control.
    UCA0CTL1 &= ~UCSWRST; //this enables Rx and Txhardware

    IE2 |= UCA0RXIE;
}



interrupt(TIMER0_A0_VECTOR) timer_blink(void) {
    //generate delay for 500ms
    count++;
    if(count >= 20)  {
        P1OUT ^= (BIT0 + BIT6);
        count = 0;
    }
}

interrupt(USCIAB0RX_VECTOR) echo(void) {
    while(!(IFG2 & UCA0TXIFG));
    UCA0TXBUF = UCA0RXBUF; //echo
}

int main(int argc, const char *argv[])
{
    WDTCTL = WDTPW + WDTHOLD;

    P1DIR = BIT0 + BIT6;
    P1OUT = BIT0;

    if(CALBC1_1MHZ != 0xff) { //set up for 1Mhz operting freq.
        DCOCTL=0;
        BCSCTL1 = CALBC1_1MHZ;
        DCOCTL = CALDCO_1MHZ;
    }
    uart_init();
    init_timer_A();
    eint();
    LPM0;
    while(1) {
    }
    return 0;
}