File content as of revision 7:024ace6d943c:

#include "mbed.h"
#define ONE_MILLION 1000000

static Ticker ticker;
static volatile uint64_t unixTime16ths;
static void tick(void)
{
    unixTime16ths++;
}
void TimeSet(uint32_t t)
{
    unixTime16ths = (uint64_t)t << 4;
}
uint32_t TimeGet()
{
    return unixTime16ths >> 4;
}
void TimeSet16ths(uint64_t t)
{
    unixTime16ths = t;
}
uint64_t TimeGet16ths()
{
    return unixTime16ths;
}
void TimeToTm(uint32_t time, struct tm* ptm)
{
    int seconds  = time % 60; time /= 60;
    int minutes  = time % 60; time /= 60;
    int hours    = time % 24; time /= 24;
    int daysLeft = time;
    
    //Add a year at a time while there is more than a year of days left
    int year      = 1970; //Unix epoch is 1970
    int dayOfWeek = 4;    //1 Jan 1970 is a Thursday
    int dayOfYear;
    int leapYear;
    while(1)
    {
        //See if it is a leap year
        int year4   = !(year %   4);
        int year100 = !(year % 100);
        int year400 = !(year % 400);
                     leapYear = false;
        if (year4)   leapYear =  true;
        if (year100) leapYear = false;
        if (year400) leapYear =  true;
        
        //Find the number of days in this year
        int daysInYear = leapYear ? 366 : 365;
        
        //Stop if this is the final year
        if (daysLeft < daysInYear) break;
        
        //Calculate the current day of the week at the start of the year
        dayOfWeek += leapYear ? 2 : 1;
        if (dayOfWeek >= 7) dayOfWeek -= 7;
        
        //Move on to the next year
        daysLeft -= daysInYear;
        year++;
    }
    
    dayOfYear = daysLeft;
    dayOfWeek += daysLeft;
    dayOfWeek %= 7;

    //Add a month at a time while there is more than a month of days left
    int month = 0;
    while(1)
    {
        int daysInMonth;
        switch (month + 1)
        {
            case  1: daysInMonth = 31; break;
            case  2: daysInMonth = leapYear ? 29 : 28; break;
            case  3: daysInMonth = 31; break;
            case  4: daysInMonth = 30; break;
            case  5: daysInMonth = 31; break;
            case  6: daysInMonth = 30; break;
            case  7: daysInMonth = 31; break;
            case  8: daysInMonth = 31; break;
            case  9: daysInMonth = 30; break;
            case 10: daysInMonth = 31; break;
            case 11: daysInMonth = 30; break;
            case 12: daysInMonth = 31; break;
        }
        
        //Stop if this is the last month
        if (daysLeft < daysInMonth) break;
        
        //Move onto next month
        daysLeft -= daysInMonth;
        month++;
    }

  ptm->tm_sec  = seconds;
  ptm->tm_min  = minutes;
  ptm->tm_hour = hours;
  ptm->tm_mday = daysLeft + 1;
  ptm->tm_mon  = month;
  ptm->tm_year = year - 1900;
  ptm->tm_wday = dayOfWeek;
  ptm->tm_yday = dayOfYear;
}
void TimeGetTm(struct tm* ptm)
{
    uint32_t time = TimeGet();    
    TimeToTm(time, ptm);
}
static Timer timer;
int TimeScanUs = 0;
int TimeMain()
{
    int scanUs = timer.read_us();
    timer.reset();
    timer.start();
    if (scanUs > TimeScanUs) TimeScanUs++;
    if (scanUs < TimeScanUs) TimeScanUs--;
    return 0;
}
int TimeInit()
{
    ticker.attach_us(&tick, ONE_MILLION >> 4);
    timer.stop();
    timer.reset();
    return 0;
}