In contiki programs, the usage of rtimer is important when we need a real-time functionality. While having different kinds of timers such as ctimer and etimer, the most accurate timing can be achieved by using rtimer. Recently had such a requirement where my program should have very accurate timing. So, I learned about rtimer and used it in my program. For the sake of remembering it, I'm writing down a simple program which use rtimer.
The program shown below is a modified version of the hellow-world program which is in /contiki-2.6/examples/hello-world directory. Therefore I can run it just by issuing the following command in terminal inside that directory.
make TARGET=cooja hello-world
Our program will keep printing Hello from rtimer!!! as the output.
The program shown below is a modified version of the hellow-world program which is in /contiki-2.6/examples/hello-world directory. Therefore I can run it just by issuing the following command in terminal inside that directory.
make TARGET=cooja hello-world
1: #include "contiki.h"
2: #include <stdio.h>
3: #include "sys/rtimer.h"
4: #define PERIOD_T 5*RTIMER_SECOND
5:
6: static struct rtimer my_timer;
7:
8: PROCESS(hello_world_process, "Hello world process");
9: AUTOSTART_PROCESSES(&hello_world_process);
10:
11: // the function which gets called each time the rtimer triggers
12: static char periodic_rtimer(struct rtimer *rt, void* ptr){
13: uint8_t ret;
14: rtimer_clock_t time_now = RTIMER_NOW();
15:
16: printf("Hello from rtimer!!!\n");
17:
18: ret = rtimer_set(&my_timer, time_now + PERIOD_T, 1,
19: (void (*)(struct rtimer *, void *))periodic_rtimer, NULL);
20: if(ret){
21: printf("Error Timer: %u\n", ret);
22: }
23: return 1;
24: }
25:
26: PROCESS_THREAD(hello_world_process, ev, data)
27: {
28: PROCESS_BEGIN();
29:
30: printf("Starting the application...\n");
31:
32: periodic_rtimer(&my_timer, NULL);
33:
34: while(1){
35: PROCESS_YIELD();
36: }
37: PROCESS_END();
38: }
Our program will keep printing Hello from rtimer!!! as the output.
