adc.c

/*
 * adc.c
 *
 *  Created on: Mar 28, 2023
 *      Author: jtyost
 */
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <inc/tm4c123gh6pm.h>
#include "lcd.h"
#include "Timer.h"
#include "math.h"
#include "adc.h"

void adc_init(void) {
      SYSCTL_RCGCADC_R |= 0x1;   // 1) activate ADC0
      SYSCTL_RCGCGPIO_R |= 0x2;    // 2) activate clock for Port B
      while((SYSCTL_PRGPIO_R & 0x2) != 0x2){};  // 3 for stabilization
      GPIO_PORTB_DIR_R &= ~0x10;    // 4) make PB4 input
      GPIO_PORTB_AFSEL_R |= 0x10;   // 5) enable alternate function on PB4
      GPIO_PORTB_DEN_R &= ~0x10;    // 6) disable digital I/O on PB4
      GPIO_PORTB_AMSEL_R |= 0x10;   // 7) enable analog functionality on PB4
      while((SYSCTL_PRADC_R & 0x0001) != 0x0001){};
      ADC0_ACTSS_R &= ~0x0008;      // 10) disable sample sequencer 3
      ADC0_EMUX_R &= ~0xF000;       // 11) seq3 is software trigger
      ADC0_SSMUX3_R &= ~0x000F;
      ADC0_SSMUX3_R += 10;           // 12) set channel
      ADC0_SSCTL3_R = 0x0006;       // 13) no TS0 D0, yes IE0 END0
      ADC0_IM_R &= ~0x0008;         // 14) disable SS3 interrupts
      ADC0_ACTSS_R |= 0x0008;       // 15) enable sample sequencer 3
}


uint16_t adc_read(void) {
      uint32_t result;
      ADC0_PSSI_R = 0x0008;
      while((ADC0_RIS_R & 0x08) == 0) {};
      result = ADC0_SSFIFO3_R & 0xFFF;
      ADC0_ISC_R = 0x0008;
      return result;
}
double adc_distance(void){
    double scan;
    double result;

    scan = adc_read();
    scan = (1/scan);
    result = (10.07143 * scan);

    return result;
}