#include "msp.h"
void ClockSetup(void);
void BT_UART_PIN_SETUP(void);
char testing = 'a';
char testing123[11] = {'H', 'E', 'L', 'L', 'O', ' ', 'W', 'O', 'R', 'L', 'D'};
int enumerator = 0;

int main(void)
{
    WDT_A->CTL = WDT_A_CTL_PW | // Stop watchdog timer
            WDT_A_CTL_HOLD;
    ClockSetup();
    BT_UART_PIN_SETUP();
    ClockSetup();
    // Enable global interrupt
    __enable_irq();
    //while (1){
        //EUSCI_A0->TXBUF = '0';
        //EUSCI_A1->TXBUF = '0';
        //EUSCI_A2->TXBUF = '0';
    //}
}

void BT_UART_PIN_SETUP(){ //enable pins for UART comm
    // Baud Rate calculation
    // 12000000/(16*9600) = 78.125
    // Fractional portion = 0.125
    // User's Guide Table 21-4: UCBRSx = 0x10
    // UCBRFx = int ( (78.125-78)*16) = 2

    P3->SEL0 |= (BIT3 + BIT2); // P3.2 RX
    P3->SEL1 &= ~(BIT3 + BIT3); // P3.3 TX
    // Configure UART
    EUSCI_A2->CTLW0 |= EUSCI_A_CTLW0_SWRST; // Put eUSCI in reset
    EUSCI_A2->CTLW0 = EUSCI_A_CTLW0_SWRST | // Remain eUSCI in reset
    EUSCI_B_CTLW0_SSEL__SMCLK; // Configure eUSCI clock source for SMCLK
    EUSCI_A2->BRW = 78; // 12000000/16/9600
    EUSCI_A2->MCTLW = (2 << EUSCI_A_MCTLW_BRF_OFS) |
    EUSCI_A_MCTLW_OS16;
    EUSCI_A2->CTLW0 &= ~EUSCI_A_CTLW0_SWRST; // Initialize eUSCI
    EUSCI_A2->IFG &= ~EUSCI_A_IFG_RXIFG; // Clear eUSCI RX interrupt flag
    EUSCI_A2->IE |= EUSCI_A_IE_RXIE; // Enable USCI_A1 RX interrupt
// Enable eUSCIA1 interrupt in NVIC module
    NVIC->ISER[0] = 1 << ((EUSCIA2_IRQn) & 31);
}

// UART interrupt service routine
void EUSCIA2_IRQHandler(){
    //EUSCI_A2->TXBUF = 'A';
    EUSCI_A2->TXBUF = testing123[enumerator % 11];

    enumerator = enumerator + 1;

    EUSCI_A2->IFG &= ~EUSCI_A_IFG_RXIFG;
}

void ClockSetup(void){
    CS->KEY = CS_KEY_VAL; // Unlock CS module for register access
    CS->CTL0 = 0; // Reset tuning parameters
    CS->CTL0 = CS_CTL0_DCORSEL_3; // Set DCO to 12MHz (nominal, center of 8-16MHz range)
    CS->CTL1 = CS_CTL1_SELA_2 | // Select ACLK = REFO
            CS_CTL1_SELS_3 | // SMCLK = DCO
            CS_CTL1_SELM_3; // MCLK = DCO
    CS->KEY = 0; // Lock CS module from unintended accesses
}