Francis Schumacher / Mbed 2 deprecated nRF51_rtc_example

This program is an example of an attempt at a Real Time Clock on the nRF51-DK.

Dependencies:   mbed nrf51_rtc

main.cpp@1:c1f06d0a5e11, 2015-02-08 (annotated)

Committer:
fxschumacher
Date:
Sun Feb 08 01:45:35 2015 +0000
Revision:
1:c1f06d0a5e11
Parent:
0:8a9f15c4effd 
Example program for using a Real Time Clock with the nRF51-DK.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
fxschumacher 0:8a9f15c4effd 1 /*
fxschumacher 0:8a9f15c4effd 2 This example code shows one way of creating a real time clock for the nRF51 without interfering with the mbed library functions
fxschumacher 0:8a9f15c4effd 3
fxschumacher 0:8a9f15c4effd 4 Two methods are created to replace the similarly named C routines: rtc.time and rtc.set_time.
fxschumacher 0:8a9f15c4effd 5 If the rtc.time method isn't called frequently (< 512 seconds between calls), a ticker (from the mbed library) is required
fxschumacher 0:8a9f15c4effd 6 to keep the time updated.
fxschumacher 0:8a9f15c4effd 7
fxschumacher 0:8a9f15c4effd 8 In this example, LED2 toggles and the time is printed when button1 is pushed. LED1 will toggle when the time is periodically updated.
fxschumacher 0:8a9f15c4effd 9
fxschumacher 0:8a9f15c4effd 10 references:
fxschumacher 0:8a9f15c4effd 11 -- see NRF_RTC_Type in nrf51.h
fxschumacher 0:8a9f15c4effd 12 (e.g.: http://developer.mbed.org/users/mbed_official/code/mbed-src/file/12a9a5f8fea0/targets/cmsis/TARGET_NORDIC/TARGET_MCU_NRF51822/nrf51.h)
fxschumacher 0:8a9f15c4effd 13 -- see "nRF51 Series Reference Manual" chapter on Real Time Counter (chapter 19 in V3.0)
fxschumacher 0:8a9f15c4effd 14 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,
fxschumacher 0:8a9f15c4effd 15 so you can read, but don't write!
fxschumacher 0:8a9f15c4effd 16
fxschumacher 0:8a9f15c4effd 17 */
fxschumacher 0:8a9f15c4effd 18
fxschumacher 0:8a9f15c4effd 19 #include "mbed.h"
fxschumacher 0:8a9f15c4effd 20 #include "nrf51_rtc.h"
fxschumacher 0:8a9f15c4effd 21
fxschumacher 0:8a9f15c4effd 22 // used for the example only, not required for rtc use
fxschumacher 0:8a9f15c4effd 23 DigitalOut rtc_update_led(LED1); // toggle when update_rtc is called
fxschumacher 0:8a9f15c4effd 24 DigitalOut button_push_led(LED2); // toggle when button1 is pushed
fxschumacher 0:8a9f15c4effd 25 DigitalIn button1(BUTTON1); // used to trigger the time report
fxschumacher 0:8a9f15c4effd 26 InterruptIn button1Press(BUTTON1);
fxschumacher 0:8a9f15c4effd 27 Serial pc(USBTX,USBRX);
fxschumacher 0:8a9f15c4effd 28
fxschumacher 0:8a9f15c4effd 29 time_t example_time() {
fxschumacher 0:8a9f15c4effd 30 // set an intial time
fxschumacher 0:8a9f15c4effd 31 // ...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)
fxschumacher 0:8a9f15c4effd 32 time_t rawtime=0;
fxschumacher 0:8a9f15c4effd 33
fxschumacher 0:8a9f15c4effd 34 struct tm * init_timeinfo;
fxschumacher 0:8a9f15c4effd 35
fxschumacher 0:8a9f15c4effd 36 // initialize time
fxschumacher 0:8a9f15c4effd 37 init_timeinfo = localtime(&rawtime); // note: must initialize the struct with this before trying to set components
fxschumacher 0:8a9f15c4effd 38 // ...else code goes into the weeds!!
fxschumacher 0:8a9f15c4effd 39 init_timeinfo->tm_sec = 0;
fxschumacher 0:8a9f15c4effd 40 init_timeinfo->tm_min = 10;
fxschumacher 0:8a9f15c4effd 41 init_timeinfo->tm_hour = 17;
fxschumacher 0:8a9f15c4effd 42 init_timeinfo->tm_mon = 1;
fxschumacher 0:8a9f15c4effd 43 init_timeinfo->tm_mday = 7;
fxschumacher 0:8a9f15c4effd 44 init_timeinfo->tm_year = 2015 - 1900;
fxschumacher 0:8a9f15c4effd 45
fxschumacher 0:8a9f15c4effd 46 char date[24];
fxschumacher 0:8a9f15c4effd 47 strftime(date,sizeof(date),"%H:%M:%S on %m/%d/%G",init_timeinfo);
fxschumacher 0:8a9f15c4effd 48 pc.printf("Initial time set is %s.\r\n",date);
fxschumacher 0:8a9f15c4effd 49
fxschumacher 0:8a9f15c4effd 50 // compute the proper value for time in time_t type
fxschumacher 0:8a9f15c4effd 51 rawtime = mktime(init_timeinfo);
fxschumacher 0:8a9f15c4effd 52 return rawtime;
fxschumacher 0:8a9f15c4effd 53 }
fxschumacher 0:8a9f15c4effd 54 void print_time() {
fxschumacher 0:8a9f15c4effd 55 // called when a button is pushed, this prints the current time to the USB-connected console
fxschumacher 0:8a9f15c4effd 56 button_push_led = !button_push_led;
fxschumacher 0:8a9f15c4effd 57
fxschumacher 0:8a9f15c4effd 58 time_t rawtime=rtc.time();
fxschumacher 0:8a9f15c4effd 59
fxschumacher 0:8a9f15c4effd 60 // massage the time into a human-friendly format for printing
fxschumacher 0:8a9f15c4effd 61 struct tm * timeinfo;
fxschumacher 0:8a9f15c4effd 62 timeinfo = localtime(&rawtime);
fxschumacher 0:8a9f15c4effd 63 char date[24];
fxschumacher 0:8a9f15c4effd 64 strftime(date,sizeof(date),"%H:%M:%S on %m/%d/%G",timeinfo);
fxschumacher 0:8a9f15c4effd 65 pc.printf("The current time is %s.\r\n",date);
fxschumacher 0:8a9f15c4effd 66 }
fxschumacher 0:8a9f15c4effd 67
fxschumacher 0:8a9f15c4effd 68 // (probably) required for rtc use
fxschumacher 0:8a9f15c4effd 69 void update_rtc() {
fxschumacher 0:8a9f15c4effd 70 // for use as interrupt routine, to insure that RTC is updated periodically
fxschumacher 0:8a9f15c4effd 71 // ...if rtc is not read before the underlying counter rolls over (typically 512 seconds), the RTC value will be wrong
fxschumacher 0:8a9f15c4effd 72 // ...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)
fxschumacher 0:8a9f15c4effd 73 rtc.time();
fxschumacher 0:8a9f15c4effd 74 rtc_update_led = !rtc_update_led;
fxschumacher 0:8a9f15c4effd 75 }
fxschumacher 0:8a9f15c4effd 76
fxschumacher 0:8a9f15c4effd 77
fxschumacher 0:8a9f15c4effd 78 int main(void)
fxschumacher 0:8a9f15c4effd 79 {
fxschumacher 0:8a9f15c4effd 80 rtc_update_led=0;
fxschumacher 0:8a9f15c4effd 81 button_push_led=0;
fxschumacher 0:8a9f15c4effd 82
fxschumacher 0:8a9f15c4effd 83 // user selectable, any time < 512 seconds is OK
fxschumacher 0:8a9f15c4effd 84 #define PERIODIC_UPDATE 1
fxschumacher 0:8a9f15c4effd 85 Ticker rtc_ticker;
fxschumacher 0:8a9f15c4effd 86 rtc_ticker.attach(&update_rtc, PERIODIC_UPDATE); // update the time regularly
fxschumacher 0:8a9f15c4effd 87
fxschumacher 0:8a9f15c4effd 88 time_t initial_time = example_time();
fxschumacher 0:8a9f15c4effd 89 rtc.set_time(initial_time);
fxschumacher 0:8a9f15c4effd 90
fxschumacher 0:8a9f15c4effd 91 button1Press.fall(&print_time); // when button1 is pressed, this calls rtc.time() and prints it
fxschumacher 0:8a9f15c4effd 92
fxschumacher 0:8a9f15c4effd 93 while (true) {
fxschumacher 0:8a9f15c4effd 94 sleep();
fxschumacher 0:8a9f15c4effd 95 }
fxschumacher 0:8a9f15c4effd 96 }
fxschumacher 0:8a9f15c4effd 97