Photoresistor Code

#include "msp.h"
#include "math.h"

#define DELAY 1200000
#define ADC P5
#define PHOTO_ADC BIT5
#define PHOTO P2
#define PHOTO_LED BIT7

void delaysetup (void);
void delayms (uint16_t delay);
void ADC14_init (void);
void TA_init (void);
void level_assign(void);

float ref_voltage = 3.5;
float NADC, brightness;
float max = 2.5, min = 1.5; //max and min voltages from ambient conditions
float pwm_LED = 0;

void main(void){

    WDT_A->CTL = WDT_A_CTL_PW | WDT_A_CTL_HOLD;     // stop watchdog timer

    ADC14_init(); //for A0
    TA_init();

    while(1){

        level_assign();

        ADC14 -> CTL0 |= ADC14_CTL0_SC; //starts conversion
        NADC = ADC14->MEM[0];
        brightness = ref_voltage * (NADC / pow(2, 14)); //reference pin voltage 3.3V mult by ADC resolution (adc/2^14)

        if(brightness > max) //max brightness error check
            max = brightness;

        if(brightness < min) //min brightness error check
            min = brightness;

        TIMER_A0->CCR[4] = (pwm_LED); //period mult by LED brightness val for brightness
    }
}

void ADC14_init (void) {

    ADC->SEL0 |= PHOTO_ADC;                   // configure pin 5.5 for A0 input
    ADC->SEL1 |= PHOTO_ADC;

    ADC14->CTL0 &=~ 0x00000002;         // disable ADC14ENC during configuration
    ADC14->CTL0 |= 0x44200210;          // S/H pulse mode, SMCLK, 16 sample clocks
    ADC14->CTL1 = 0x00000030;           // 14 bit resolution
    ADC14->CTL1 |= 0x00000000;          // Selecting ADC14CSTARTADDx mem0 REGISTER
    ADC14->MCTL[0] = 0;                 // ADC14INCHx = 0 for mem[0]
    ADC14->CTL0 |= 0x00000002;          // enable ADC14ENC, starts the ADC after configuration
}
void TA_init (void) {
    //TA0.4 connected to led on pin PHOTO.7
    PHOTO->SEL0 |= PHOTO_LED;
    PHOTO->SEL1 &= ~PHOTO_LED;
    PHOTO->DIR |= PHOTO_LED;

    TIMER_A0->CCR[0]= 12000-1;                      // CCR0 PWM period for LED
    TIMER_A0->CCTL[4] = TIMER_A_CCTLN_OUTMOD_7;     // CCTL reset/set
    TIMER_A0->CCR[4] = pwm_LED;                     // CCR4 PWM duty cycle
    TIMER_A0->CTL = 0x0290;                     //SMCLK, /4, up mode, no interrupts
}

void level_assign(){ //check brightness and assign to a level to print

    //math: 14460 min to 14670 max:
    if(NADC < 14560)
        pwm_LED = 0;
    else if ((14560 <= NADC) && (NADC <= 14584))
        pwm_LED = 1450;
    else if ((14585 <= NADC) && (NADC <= 14608))
        pwm_LED = 2900;
    else if ((14609 <= NADC) && (NADC <= 14632))
        pwm_LED = 4340;
    else if ((14633 <= NADC) && (NADC <= 14656))
        pwm_LED = 5800;
    else if ((14657 <= NADC) && (NADC <= 14680))
        pwm_LED = 7250;
    else if ((14681 <= NADC) && (NADC <= 14704))
        pwm_LED = 8700;
    else if ((14705 <= NADC) && (NADC <= 14728))
        pwm_LED = 10150;
    else if ((14729 <= NADC) && (NADC <= 14752))
        pwm_LED = 11600;
    else if ((14753 <= NADC) && (NADC <= 14776))
        pwm_LED = 13050;
    else if (14777 < NADC)
        pwm_LED = 14500;

}