Unstable resume task

[Avicar]

Hello,
I need to delay a task for variable times between 1500 to 4500 microseconds. To do so I used the High Resolution Timer (ESP Timer).
To check that implementation I came up with the following piece of code:

Code: [Select all] [Expand/Collapse]

1. #include <stdio.h>
2. #include "freertos/FreeRTOS.h"
3. #include "freertos/task.h"
4. #include "esp_log.h"
5. #include <esp_err.h>
6. #include <sys/stat.h>
7. #include "freertos/timers.h"
8. #include "esp_timer.h"
9. #include "sdkconfig.h"
10.  
11. esp_timer_handle_t theTimer_handler;
12. TaskHandle_t task_handler = NULL;
13.  
14.  
15. static void timer_callback(void *param){
16.    
17.     vTaskResume(task_handler);
18.     printf("task state: %d\n",(int)eTaskGetState( task_handler ));
19.     printf("Timer: %lld μs\n",esp_timer_get_time());
20. }
21.  
22.  
23. void initTimer(){
24.     // define timmer
25.     const esp_timer_create_args_t timer_args = {
26.         .callback = &timer_callback,
27.         .name = "Timer"};
28.  
29.     // create timmer
30.     ESP_ERROR_CHECK(esp_timer_create(&timer_args, &theTimer_handler));
31. }
32.  
33.  
34. static void the_task(void *arg)
35. {
36.    
37.    ESP_ERROR_CHECK(esp_timer_start_once(theTimer_handler, 2800));
38.     vTaskSuspend(task_handler); // wait for next time
39.    
40.     while (1) {
41.         ESP_ERROR_CHECK(esp_timer_start_once(theTimer_handler, 2800));
42.         long long int Timer = esp_timer_get_time();
43.        
44.         printf("SYS Timer: %lld μs\n",esp_timer_get_time());
45.         vTaskSuspend(task_handler); // wait for next time
46.         printf("back\n");
47.     }
48. }
49.  
50. void app_main(void)
51. {
52.  
53.  
54.     initTimer();
55.    
56.     xTaskCreatePinnedToCore(the_task, "the_task",8196 , NULL, 5, &task_handler,1);
57.    
58.     while (1){
59.          vTaskDelay(1000 / portTICK_PERIOD_MS);
60.     }
61.    
62.  
63. }
64. [/code]

GeSHi © Codebox Plus Extension

The problem is whenever I decrease the timer to less than 3000 microseconds the program will hang after several iterations. I believe it hangs due to the fact that the task is not in suspend state when the timer is off. I can't understand why the task can't enter the suspend state as there is ample time to do that (in order of few milliseconds).
Here is a sample of the last part of the code output:

SYS Timer: 2465120 μs
task state: 1
Timer: 2468504 μs
back
SYS Timer: 2470762 μs
task state: 1
Timer: 2474146 μs
back
SYS Timer: 2476404 μs
task state: 1
Timer: 2479789 μs
back
SYS Timer: 2482047 μs
task state: 1
Timer: 2485431 μs
back
SYS Timer: 2487689 μs
task state: 1
Timer: 2491073 μs
back
SYS Timer: 2493331 μs
task state: 1
back
Timer: 2496727 μs
SYS Timer: 2497243 μs
task state: 0
Timer: 2502354 μs

Any idea about what am I doing wrong?

[MicroController]

Don't use vTaskSuspend/vTaskResume - like, ever.
In your case, the "direct-to-task notification" mechanism is exactly what you want. A more general solution is using semaphores.

[Avicar]

Just for whomever interested, I followed @microcontroller great advice and came up with that code:

Code: [Select all] [Expand/Collapse]

1. #include <stdio.h>
2. #include "freertos/FreeRTOS.h"
3. #include "freertos/task.h"
4. #include "esp_log.h"
5. #include <esp_err.h>
6. #include <sys/stat.h>
7. #include "freertos/timers.h"
8. #include "esp_timer.h"
9. #include "sdkconfig.h"
10.  
11. esp_timer_handle_t theTimer_handler;
12. TaskHandle_t task_handler = NULL;
13.  
14.  
15. static void timer_callback(void *param){
16.    
17.     //vTaskResume(task_handler);
18.     xTaskNotifyGive(task_handler);
19.     printf("task state: %d\n",(int)eTaskGetState( task_handler ));
20.     printf("Timer: %lld μs\n",esp_timer_get_time());
21. }
22.  
23.  
24. void initTimer(){
25.     // define timmer
26.     const esp_timer_create_args_t timer_args = {
27.         .callback = &timer_callback,
28.         .name = "Timer"};
29.  
30.     // create timmer
31.     ESP_ERROR_CHECK(esp_timer_create(&timer_args, &theTimer_handler));
32. }
33.  
34.  
35. static void the_task(void *arg)
36. {
37.     while (1) {
38.         ESP_ERROR_CHECK(esp_timer_start_once(theTimer_handler, 2800));
39.         long long int Timer = esp_timer_get_time();
40.  
41.         ulTaskNotifyTake(pdTRUE,portMAX_DELAY);
42.         printf("End Timer: %lld μs\n",esp_timer_get_time()-Timer);
43.         }
44. }
45.  
46. void app_main(void)
47. {
48.  
49.  
50.     initTimer();
51.    
52.     xTaskCreatePinnedToCore(the_task, "the_task",8196 , NULL, 5, &task_handler,1);
53.    
54.     while (1){
55.          vTaskDelay(1000 / portTICK_PERIOD_MS);
56.     }
57.    
58.  
59. }

GeSHi © Codebox Plus Extension

Which works great.