/*#############################################################

Program Name    : ex3_F446RE_SDCardLoggerWrite
Author          : Grant Phillips
Date Modified   : 19/09/2016
Compiler        : ARMmbed
Tested On       : NUCLEO-F446RE

Description     : Example program that demonstrates the use of
                  a SDCard with the NUCLEO board.  Everytime the
                  button is pushed, the current time and analog
                  input value gets logged to a file.

Requirements    : * NUCLEO-F446RE Board
              
Circuit         : * a potentiometer (POT) connected to PC0
                  * the USER pushbutton connected to PC13
                  * The SDCard connected as:
                    
                    VCC         -       +3V or +5V (depending on module)
                    GND         -       GND
                    SS/CS       -       PB_6
                    MOSI        -       PB_5 (SPI3_MOSI)
                    MISO        -       PB_4 (SPI3_MISO)
                    SCK         -       PB_3 (SPI3_SCK)
                    
##############################################################*/

#include "mbed.h"
#include "SDFileSystem.h"           //Niel Thiessen's library

Serial pc(SERIAL_TX, SERIAL_RX);    //to use the PC as a console (display output)
 
DigitalOut myled(LED1);             //LED to indicate system operation
 
SDFileSystem sd(PB_5, PB_4, PB_3, PB_6, "sd"); //create a SDFileSystem object
//              mosi, miso, sck , cs  , name

AnalogIn ain(PC_0);     //analog input pin
DigitalIn pb(PC_13);    //USER pushbutton

int main()
{      
    char date[32];      //string for storing the current date
    char timeofday[32]; //string for storing the current time
    
    time_t seconds;     //time_t variable to read the number of seconds since January 1, 1970 for time calculations
    struct tm t;        //time structure for setting the time
    
    //set time structure to 20 Sep 2016 00:31:01
    t.tm_year = 2016 - 1900;
    t.tm_mon = 9 - 1;
    t.tm_mday = 20;
    t.tm_hour = 0;
    t.tm_min = 31;
    t.tm_sec = 1;
    
    //use the time structure and set the real-time clock (RTC) time
    set_time(mktime(&t));
    
    pc.printf("ex3_F446RE_SDCardLoggerWrite\n\n");
    
    pc.printf("Press button to log a analog input value...\n");

    while(1) {
        if(pb == 0) {                               //when the button is pressed...
            FILE *fp = fopen("/sd/log.txt", "a");   //open a file for appending/adding("a"); if the file doesn't exist
                                                    //it will be created; if it exists text will be added/appended to the
                                                    //end of the file
            
            if(fp == NULL) {                        //if error opening
                printf("Could not open file for write!\n");
            }
            else {
                seconds = time(NULL);                                           //read the new time value
                strftime(date, 32, "%d/%m/%y", localtime(&seconds));            //create a date string from the time value
                strftime(timeofday, 32, "%H:%M:%S", localtime(&seconds));       //create a time string from the time value
                
                fprintf(fp, "%s %s %d\r\n", date, timeofday, ain.read_u16());   //write the date string, time string, and analog integer value to the file
                                                                                //the /r/n combination puts the entries on different lines in the file
                fclose(fp);                                                     //close the file to prevent corrupt files
                pc.printf("Temperature recorded.\n");
                wait(0.5);                                                      //delay to debounce the pushbutton
            } 
        }      
        
        myled = !myled;                             //flash led
        wait(0.1);
    }
}