#include <msp430.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>

//Variables

volatile unsigned int ADC_value = 0;

void UART_init(void)
{

/* Configure UART pins (P4.2 = RXD, P4.3 = TXD) */
	
	P4SEL0 |= BIT2 | BIT3;                    			// Set P4.2 and P4.3 to UART mode
	P4SEL1 &= ~(BIT2 | BIT3);

	UCA1CTLW0	|= UCSWRST;					// Put eUSCI_A1 in reset
	UCA1CTLW0	|= UCSSEL__SMCLK;				// Choose SMCLK clock source

/*	Baud Rate Calculation for 9600 baud with 1,000,000 Hz SMCLK:
  	1000000 / 9600 = 104.166 -> UCBRx = 104, fractional portion = 0.166
  	Using Table 22-4 from User's Guide: UCBRSx = 0x11*/ 

	UCA1BR0		= 0x68;						// 1MHz 9600 baud
	UCA1BR1		= 0;
	UCA0MCTLW	= 0x1100;
	
	UCA1CTLW0	&= ~UCSWRST;					// Initialize eUSCI state machine
	UCA1IE		|= UCTXIE;				 	// Enable USCI_A1 TX interrupt
	
	__bis_SR_register(GIE);
	__no_operation();
}

int main(void)
{
	WDTCTL = WDTPW | WDTHOLD;	            			// stop watchdog timer
	
/* Disable the GPIO power-on default high-impedance mode to activate
 * previously configured port settings*/

	PM5CTL0 &= ~LOCKLPM5;

	UART_init();

/* Configure ADC Channel Pins*/

	P1SEL1 |= BIT4;                         			// Configure P1.4 for ADC
	P1SEL0 |= BIT4;

/* Configure ADC12 */

	ADCCTL0     =   ADCSHT_2 | ADCON;       			// ADCON, S&H=16 ADC clks
	ADCCTL1     =   ADCSHP;                 			// ADCCLK = MODOSC; sampling timer; ADC conversion start source is ADCSC bit
	ADCCTL2     =   ADCRES_2;               			// Set ADCRES_2 to binary 10 for 12 bit resolution
	ADCIE       |=  ADCIE0;                 			// Enable ADC conv complete interrupt
	ADCMCTL0    |=  ADCINCH_4 | ADCSREF_0;  			// ADC channel A4 selected as input and internal reference selected 000b = {VR+ = AVCC and VR- = AVSS}

/* Configure voltage reference for ADC conversion */
	PMMCTL0_H = PMMPW_H;                                      	// Unlock the PMM registers
	PMMCTL2 |= INTREFEN;                                      	// Enable internal reference 1.5V
	__delay_cycles(400);                                     	 // Delay for reference settling

	while(1)
	     {
	        ADCCTL0 |= ADCENC | ADCSC;                            	// Sampling and conversion start
	        __bis_SR_register(LPM0_bits | GIE);                  	// LPM0, ADC_ISR will force exit
	        __no_operation();
	     }
}

#pragma vector = ADC_VECTOR
__interrupt void ADC_ISR(void)

{
    switch (__even_in_range(ADCIV, ADCIV_ADCIFG))
    {
        case    ADCIV_ADCIFG: 						// ADC12MEM1 Interrupt
                ADC_value = ADCMEM0; 					// Save MEM0
                __bic_SR_register_on_exit(LPM0_bits | GIE);		// Exit CPU, clear interrupts
                break;
               default:
                break;
    }
}

#pragma vector = USCI_A1_VECTOR 					// Vector depends on specific MSP430 family variant
__interrupt void USCI_A1_ISR(void)
{
    switch(__even_in_range(UCA1IV, USCI_UART_UCTXCPTIFG))
    {
        case USCI_NONE: 
            break;
            
        case USCI_UART_UCRXIFG:
            break;
            
        case USCI_UART_UCTXIFG:
        	
            UCA1TXBUF = (ADC_value);
            break;
            
        case USCI_UART_UCSTTIFG:
            break;
            
        case USCI_UART_UCTXCPTIFG:
            break;
        default:
        	break;
    }
}