main.cpp

00001 #include "mbed.h"
00002 
00003 Serial serial(USBTX,USBRX);
00004 
00005 void serialISR();  // ISR that is called when serial data is received
00006 void setTime();    // function to set the UNIX time
00007 int setTimeFlag = 0;  // flag for ISR
00008 
00009 char rxString[16];  // buffer to store received string
00010 
00011 int main()
00012 {
00013     serial.attach(&serialISR);  // attach serial ISR
00014     char buffer[30];  // buffer used to store time string
00015     
00016     set_time(0);  // initialise time to 1st January 1970
00017 
00018     while(1) {
00019 
00020         time_t seconds = time(NULL);  // get current time
00021         // format time into a string (time and date)
00022         strftime(buffer, 30 , "%X %D", localtime(&seconds));
00023         // print over serial
00024         serial.printf("Time = %s\n",buffer);
00025         wait(1.0);  // delay for a second
00026         
00027         if (setTimeFlag) {  // if updated time has been sent
00028             setTimeFlag = 0;  // clear flag
00029             setTime(); // update time
00030         }
00031     }
00032 
00033 }
00034 
00035 void setTime() {
00036     // print time for debugging
00037     serial.printf("set_time - %s",rxString);
00038     // atoi() converts a string to an integer
00039     int time = atoi(rxString);
00040     // update the time
00041     set_time(time);
00042 }
00043 
00044 void serialISR() {
00045     // when a serial interrupt occurs, read rx string into buffer
00046     serial.gets(rxString,16);
00047     // set flag
00048     setTimeFlag = 1;    
00049 }