Group21_Project/main.c

#include <stdint.h>
#include <stdbool.h>
#include "tm4c123gh6pm.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>


#define MAX_FIELD_SIZE 100
volatile char nmea_sentence[MAX_FIELD_SIZE];
volatile uint8_t nmea_index = 0;
volatile bool nmea_ready = false;


void GPIO_PORT_F_init(void)
{
    SYSCTL_RCGC2_R |= 0x00000020;             // ENABLE CLOCK TO GPIOF
    GPIO_PORTF_LOCK_R = 0x4C4F434B;           // UNLOCK COMMIT REGISTER
    GPIO_PORTF_CR_R   = 0x1F;                 // MAKE PORTF0 CONFIGURABLE
    GPIO_PORTF_DEN_R  = 0x1F;                 // SET PORTF DIGITAL ENABLE
    GPIO_PORTF_DIR_R  = 0x0E;                 // SET PF0, PF4 as input and PF1, PF2 and PF3 as output
    GPIO_PORTF_PUR_R  = 0x11;                 // PORTF PF0 and PF4 IS PULLED UP
}


void GPIO_PORT_B_init(void)
{
    SYSCTL_RCGCGPIO_R |= 0x02;                // ENABLE CLOCK FOR GPIOB
    SYSCTL_RCGCUART_R |= 0x02;                // ENABLE CLOCK FOR UART1

    GPIO_PORTB_DEN_R |= 0x03;                 // DIGITAL ENABLE FOR PB0 AND PB1
    GPIO_PORTB_AFSEL_R |= 0x03;               // ENABLE ALTERNATE FUNCTION ON PB0,PB1

    GPIO_PORTB_PCTL_R = (GPIO_PORTB_PCTL_R & 0xFFFFFF00) | 0x00000011; // Set PB0, PB1 for UART

    UART1_CTL_R &= ~0x01;                     // DISABLE UART1 DURING SETUP
    UART1_IBRD_R = 104;                       // Set integer part of baud rate (for 9600 baud at 16 MHz clock)
    UART1_FBRD_R = 11;                        // Set fractional part of baud rate
    UART1_LCRH_R = 0x60;                      // 8-bit, No parity, 1 stop bit
    UART1_CC_R = 0x00;                        // Use system clock

    UART1_CTL_R |= 0x301;                     // Enable UART1, RX, and TX0
    UART1_IM_R |= 0x10;
    NVIC_EN0_R |= (1 << 6);
}
// Control LEDs based on speed
void control_leds_based_on_speed(float speed_kmh) {
    // Clear all LED bits (assuming LEDs are connected to bits 1, 2, and 3)
    GPIO_PORTF_DATA_R &= 0x00;

    // Determine which 5 km/h range the speed falls into
    if (speed_kmh >= 0.0 && speed_kmh < 10.0) {
        // Range 0-10 km/h
        GPIO_PORTF_DATA_R |= 0x08;  // Red LED
    } else if (speed_kmh >= 10.0 && speed_kmh < 20.0) {
        // Range 10-20 km/h
        GPIO_PORTF_DATA_R |= 0x0C;  // Blue LED
    } else if (speed_kmh >= 20.0 && speed_kmh < 30.0) {
        // Range 20-30 km/h
        GPIO_PORTF_DATA_R |= 0x04;  // Green LED
    } else if (speed_kmh >= 30.0 && speed_kmh < 40.0) {
        // Range 30-40 km/h
        GPIO_PORTF_DATA_R |= 0x06;  // Yellow LED (Red + Green)
    } else if (speed_kmh >= 40.0 && speed_kmh < 50.0) {
        // Range 40-50 km/h
        GPIO_PORTF_DATA_R |= 0x02;  // Blue LED
    } else {
        // Above 50 km/h
        GPIO_PORTF_DATA_R |= 0x0E;  // Maximum LED (Red + Blue + Green)
    }
}



void nmea_sentence_process(const char *nmea_sentence)
{
    uint8_t i = 0;
    uint8_t field_number = 0;
    float speed_kmh = 0.0;
    uint8_t field_index = 0;

    if (nmea_sentence[0] != '$') return;  // Invalid sentence, exit

    if (strncmp(nmea_sentence + 1, "GPRMC", 5) == 0)
    {
     for (i = 6; nmea_sentence[i] != '\0'; i++)
     {
       if (nmea_sentence[i] == ',')
       {
          if (field_number == 7) // Speed in knots (field 7)
          {  speed_kmh = atof(nmea_sentence + i - field_index);
             control_leds_based_on_speed(speed_kmh);
          }
             field_number++;
             field_index = 0;
        }
       else if (nmea_sentence[i] == '*')
        {
           break;
        }
       else
        {
          field_index++;
        }
      }
     }
    else if (strncmp(nmea_sentence + 1, "GPVTG", 5) == 0)  // Process GPVTG sentence
    {
     for (i = 7; nmea_sentence[i] != '\0'; i++)
     {
     if (nmea_sentence[i] == ',')
       {
       if (field_number == 6)
           {
              speed_kmh = atof(nmea_sentence + i - field_index);
              control_leds_based_on_speed(speed_kmh);
           }
              field_number++;
              field_index = 0;
                }
     else if (nmea_sentence[i] == '*')
          {
           break;
          }
     else {
           field_index++;
          }
         }
}


void UART1_Handler(void)
{
    char data = UART1_DR_R & 0xFF;
    if (data == '\n' || data == '\r')
    {
        nmea_sentence[nmea_index] = '\0';
        if (strncmp((const char *)nmea_sentence, "$GPRMC", 6) == 0)
        {
        nmea_ready = true;
        }
        nmea_index = 0;
    }
    else if (nmea_index < MAX_FIELD_SIZE - 1)
    {
        nmea_sentence[nmea_index++] = data;
    }
}

int main(void)
{
    GPIO_PORT_F_init();
    GPIO_PORT_B_init();
    while (1)
    {
     if (nmea_ready)
     {
      nmea_ready = false;
      process_nmea_sentence((const char *)nmea_sentence);
     }
    }
}