File content as of revision 52:99915f5240b2:

#include "SD_CARD.hpp"

FILE* fp;                           //Declaration of FILE pointer named fp
InterruptIn SD_CARD_DETECT(D0);     //Declaration of Interrupt to detect if the SD Card is present

bool SD_Write = 1;                  //Declare global variable SD_Write and initialise it to 0
bool SD_CARD_PRESENT = 1;           //Sets SD Card Present by default

//Mutex Lock
Mutex SD_CARD_Lock;

void SD_Init()                      //Function to initialise the SD Card
{
    if(SD_CARD_DETECT.read() == 0)  //Check to see when the SD card is re-inserted
    {
        if ( sd.init() != 0)        //Checks if the SD card is initialised
        {
            printf("SD Init failed \n");
            LCD.Display_Clear();
            LCD.Write_String("CANNOT INIT SD");
            errorCode(SD_FATAL);    //Throws SD_FATAL code
        }
        //Create a filing system for SD Card
        FATFileSystem fs("sd", &sd);     
                
        //Open to WRITE
                    
        FILE* fp = fopen("/sd/test.csv","w");
        if (fp == NULL) 
        {
            error("Could not open file for write\n");
            LCD.Display_Clear();
            LCD.Write_String("CANNOT OPEN FILE");
            errorCode(SD_FATAL);    //Throws SD_FATAL code
        }
        //Close File
        fclose(fp);
        LCD.Display_Clear();
        LCD.DDRAM_Address(0x00);
        LCD.Write_String("SD CARD");
        LCD.DDRAM_Address(0x40);
        LCD.Write_String("Inserted");
        pc.printf("SD CARD INSERTED\n");
        SD_Write = 1;
        return;                     //Exits Initialisation routine
    }   
}           

void SD_Card_Eject()                                                        //Function to eject the SD Card
{
    SD_Write = 0;                                                           //Set global variable SD_Write to 0
    if(Log_Value==5){pc.printf("Closing File Ejecting SD Card\n");}         //If logging is enabled, print debugging statement
    fclose(fp);                                                             //Close the opened file
    sd.deinit();                                                            //Deinitialise the SD card
    LCD.Display_Clear();                                                    //Clear the LCD Display
    LCD.DDRAM_Address(0x00);                                                //Set the LCD Write Address to 0x00
    LCD.Write_String("SD Card");                                            //Write "SD Card" to the first line of the LCD
    LCD.DDRAM_Address(0x40);                                                //Set the LCD Write Address to 0x40
    LCD.Write_String("Unmounted");                                          //Write "Unmounted" to the second line of the LCD
    LCD.DDRAM_Address(0x00);                                                //Set the LCD Write Address to 0x00
    pc.printf("SD Card Unmounted\n");                                       //Write "SD Card Unmounted" to the terminal
    
}
void SD_Write_Control(const char* SD_Write_FileToOpen, string Write_Append_Select)                  //Function to write data to a file
{
    if      (Write_Append_Select == "Append"){fp = fopen(SD_Write_FileToOpen,"a");}                 //If "Append" is selected, continue writing to existing file
    else if (Write_Append_Select == "Write" ){fp = fopen(SD_Write_FileToOpen, "w");}                //If "Write" is selected, create and write to new file
    
    if(fp == NULL)                                                                                  //If file cannot be opened
    {
        error("Could not open file for write in SD_Card\n");                                        //Print error message to terminal
        LCD.Display_Clear();                                                                        //Clear the LCD display
        LCD.Write_String("CANNOT OPEN FILE");                                                       //Write error message to LCD
        errorCode(SD_FATAL);                                                                           //Run error function - toggles red LED
    }                             
                
    if(Log_Value==5){pc.printf("File Opened\n");}                                                   //If logging is enabled, print debug statement  
                       
    for(int SD_Card_Data_Pointer = 0; SD_Card_Data_Pointer != mailsize; SD_Card_Data_Pointer++)     //For all addresses in the DATA buffer
    {
        if(Log_Value==5){pc.printf("Copying from address: %d\n", SD_Card_Data_Pointer);}            //If logging is enabled, print debug statement
        
        SD_CARD_Lock.lock();                                                                        //Apply MUTEX lock                
        time_t Time = Data_Buffer[SD_Card_Data_Pointer].get_time();                                 //Store the time from the DATA buffer
        float temp_temperature = Data_Buffer[SD_Card_Data_Pointer].get_temperature();               //Assign the temperature to a temporary value            
        float temp_pressure = Data_Buffer[SD_Card_Data_Pointer].get_pressure();                     //Assign the pressure to a temporary value
        float temp_light = Data_Buffer[SD_Card_Data_Pointer].get_light();                           //Assign the light to a temporary value
        SD_CARD_Lock.unlock();                                                                      //Release MUTEX lock
        
        tm* Time_Pointer = localtime(&Time);                                                        //Create pointer to stored time
        int temp_day = Time_Pointer->tm_mday;                                                       //Assign the day to a temporary value
        int temp_month = (Time_Pointer->tm_mon+1);                                                  //Assign the month to a temporary value
        int temp_year = (Time_Pointer->tm_year+1900);                                               //Assign the year to a temporary value
        int temp_hours = Time_Pointer->tm_hour;                                                     //Assign the hour to a temporary value 
        int temp_minute = Time_Pointer->tm_min;                                                     //Assign the minute to a temporary value
        int temp_seconds = Time_Pointer->tm_sec;                                                    //Assign the second to a temporary value
                        
        fprintf(fp, "Date: %02d/%02d/%d,",temp_day,temp_month,temp_year);                           //Print the date into column 1
        fprintf(fp, "Time: %02d:%02d:%02d,",temp_hours,temp_minute, temp_seconds);                  //Print the time into column 2
        fprintf(fp, "Temperature: %1.1f,",temp_temperature);                                        //Print the temperature into column 3
        fprintf(fp, "Pressure: %1.1f,",temp_pressure);                                              //Print the pressure into column 4
        fprintf(fp, "Light: %5.3f,\n",temp_light);                                                  //Print the light into column 5
    }            
    fclose(fp);                                                                                     //Close the file
     
}
void SD_Card_Write()                                                                        //Function to write to the SD card
{
    if(SD_Write == 0)                                                                       //If the SD card is not present
    {
        if(Log_Value==5){pc.printf("SD Has Been Ejected\n");}  //If logging is enabled, print debug statement        
        return;                                                                             //Exit function
    }
    if(Write_Pointer == mailsize - 1)                                                       //If the end of the buffer is being written to
        {
            if(Log_Value==5){pc.printf("In SD_Card Thread\n");}                             //If logging is enabled, print debug statement
    
            FATFileSystem fs("sd", &sd);                                                    //Sets working directory as "sd"
            
            SD_CARD_Lock.lock();                                                            //Apply MUTEX lock    
            time_t File_Time = Data_Buffer[Write_Pointer - 1].get_time();                   //Store the time from the data buffer
            SD_CARD_Lock.unlock();                                                          //Release MUTEX lock 
            tm* File_Time_Pointer = localtime(&File_Time);                                  //Create pointer to stored time
            int File_temp_day = File_Time_Pointer->tm_mday;                                 //Assign the day to a temporary value
            int File_temp_month = (File_Time_Pointer->tm_mon+1);                            //Assign the month to a temporary value
            int File_temp_year = (File_Time_Pointer->tm_year+1900);                         //Assign the year to a temporary value
            
            //Create a const char* using year, month and day and create a file using that name
            char FileToOpen[50] = {};
            snprintf (FileToOpen, sizeof(char) * sizeof(FileToOpen), "/sd/%d_%02d_%02d.csv",File_temp_year,File_temp_month,File_temp_day);
            
            if(fp = fopen(FileToOpen,"r"))                                                  //If the file already exists
            {
                fclose(fp);                                                                 //Close the file
                SD_Write_Control(FileToOpen, "Append");                                     //Append the existing file
            }
            else                                                                            //If the file doesn't exist
            {
                SD_Write_Control(FileToOpen, "Write");                                      //Create a new file
            }
            if(Log_Value==5){pc.printf("Dumped data to SD Card\n");}                        //If logging is enabled, print debug statement

        }
}