main.cpp

00001 /*
00002 This example code shows one way of creating a real time clock for the nRF51 without interfering with the mbed library functions
00003 
00004 Two methods are created to replace the similarly named C routines:  rtc.time and rtc.set_time.
00005 If the rtc.time method isn't called frequently (< 512 seconds between calls), a ticker (from the mbed library) is required 
00006 to keep the time updated.
00007 
00008 In this example, LED2 toggles and the time is printed when button1 is pushed.  LED1 will toggle when the time is periodically updated.
00009 
00010 references:
00011   -- see NRF_RTC_Type in nrf51.h 
00012   (e.g.:  http://developer.mbed.org/users/mbed_official/code/mbed-src/file/12a9a5f8fea0/targets/cmsis/TARGET_NORDIC/TARGET_MCU_NRF51822/nrf51.h)
00013   -- see "nRF51 Series Reference Manual" chapter on Real Time Counter (chapter 19 in V3.0)
00014 Note:  RTC2 does not exist, despite what the nrf51 reference manual (V3.0) claims.  The other RTCs (0/1) are used by various other libraries,
00015 so you can read, but don't write! 
00016 
00017 */
00018 
00019 #include "mbed.h"
00020 #include "nrf51_rtc.h"
00021 
00022 // used for the example only, not required for rtc use
00023 DigitalOut rtc_update_led(LED1); // toggle when update_rtc is called
00024 DigitalOut button_push_led(LED2); // toggle when button1 is pushed
00025 DigitalIn  button1(BUTTON1);  // used to trigger the time report
00026 InterruptIn button1Press(BUTTON1);
00027 Serial pc(USBTX,USBRX);
00028 
00029 time_t example_time() {
00030     // set an intial time
00031     //  ...not really necessary for this example, but it beats setting it to 0 or some non-obvious large integer (# of seconds since 1/1/1970)
00032     time_t rawtime=0;
00033 
00034     struct tm * init_timeinfo;
00035 
00036     // initialize time
00037     init_timeinfo = localtime(&rawtime); // note:  must initialize the struct with this before trying to set components
00038                                          // ...else code goes into the weeds!!
00039     init_timeinfo->tm_sec = 0;
00040     init_timeinfo->tm_min = 10;
00041     init_timeinfo->tm_hour = 17;
00042     init_timeinfo->tm_mon = 1;
00043     init_timeinfo->tm_mday = 7;
00044     init_timeinfo->tm_year = 2015 - 1900;        
00045 
00046     char date[24];
00047     strftime(date,sizeof(date),"%H:%M:%S on %m/%d/%G",init_timeinfo);
00048     pc.printf("Initial time set is %s.\r\n",date);
00049     
00050     // compute the proper value for time in time_t type
00051     rawtime = mktime(init_timeinfo);
00052     return rawtime;
00053 }
00054 void print_time() {
00055     // called when a button is pushed, this prints the current time to the USB-connected console
00056     button_push_led = !button_push_led; 
00057     
00058     time_t rawtime=rtc.time();
00059     
00060     // massage the time into a human-friendly format for printing
00061     struct tm * timeinfo;
00062     timeinfo = localtime(&rawtime);
00063     char date[24];
00064     strftime(date,sizeof(date),"%H:%M:%S on %m/%d/%G",timeinfo);
00065     pc.printf("The current time is %s.\r\n",date);
00066 }
00067 
00068 // (probably) required for rtc use
00069 void update_rtc() {
00070     // for use as interrupt routine, to insure that RTC is updated periodically
00071     //  ...if rtc is not read before the underlying counter rolls over (typically 512 seconds), the RTC value will be wrong
00072     //  ...ideally this would be done as part of the nrf51_rtc method, but I couldn't get it to behave (see nrf51_rtc.cpp for details)
00073     rtc.time();
00074     rtc_update_led = !rtc_update_led;
00075 }
00076 
00077 
00078 int main(void)
00079 {
00080     rtc_update_led=0;
00081     button_push_led=0;
00082     
00083     // user selectable, any time < 512 seconds is OK
00084     #define PERIODIC_UPDATE 1
00085     Ticker rtc_ticker;
00086     rtc_ticker.attach(&update_rtc, PERIODIC_UPDATE); // update the time regularly
00087     
00088     time_t initial_time = example_time();
00089     rtc.set_time(initial_time);
00090     
00091     button1Press.fall(&print_time);  // when button1 is pressed, this calls rtc.time() and prints it
00092      
00093     while (true) {
00094         sleep();
00095     }
00096 }
00097