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#include <msp430.h> 
#include "defines.h"
#include "spi.h"

int main(void) {
    WDTCTL = WDTPW | WDTHOLD;   // Stop watchdog timer

    /* --- Set Oscillator Settings (8Mhz) --------------- */
    // Set DCO to 5, MOD to 0
    DCOCTL = DCO2 | DCO0;
    // Set RSEL to 13
        BCSCTL1 = RSEL3 | RSEL2 | RSEL0;
        // MCLK = DCO/1, SMCLK = MCLK/8
        BCSCTL2 = SELM_0 | DIVM_0 | DIVS_3;
        // LFXT1 = VLOCLK, 1pF termination
        BCSCTL3 = LFXT1S_2 | XCAP_0;
        // Disable oscillator fault interrupt
        IE1 &= ~OFIE;
        /* -------------------------------------------------- */

        /* --- Set Port Settings ---------------------------- */
        // Set ports 1.5/1.6 as outputs
        // Set remaining ports as inputs
        P1DIR = BIT5 | BIT6;
        P2DIR = 0x00;
        // Enable pull-down resistors
        P1REN = ~(BIT5 | BIT6);
        P2REN = 0xFF;
        // Set initial port values
        P1OUT = 0x00;
        P2OUT = 0x00;
        /* -------------------------------------------------- */

        /* --- Set USI Settings (SPI) ----------------------- */
        // Enable SDA/SCL/SCLK ports, MSB->LSB, master mode, output enabled
        USICTL0 = USIPE7 | USIPE6 | USIPE5 | USIMST | USIOE;
        // I2C disabled, counter interrupt enabled
        USICTL1 = USIIE;
        // SMCLK/1, SMCLK source, idle low
        USICKCTL = USIDIV_0 | USISSEL_2;
        // Enable USI module (clear reset bit)
        USICTL0 &= ~USISWRST;
        /* -------------------------------------------------- */

        // Write 0 to the counter to trigger the USI interrupt
//      USICNT = 0;

        // Go into low power mode with interrupts enabled
        _BIS_SR(LPM0_bits + GIE);
}

#pragma vector=USI_VECTOR
__interrupt void USI_SPI_Vector(void) {
        char value = USISR;
        USISR = 0xAB;
        USICNT = 8;
}