Disable Timer within Timer ISR

[blengerich]

Is it possible to disable a timer within the timer ISR itself? The example code below works for Arduino Uno and Mega, but not for ESP32. The timer interrupt continues to occur, even after disabling it. The disable command doesn't seem to register within the ISR. To get this to work for ESP32, I set a flag in the ISR, and then check that flag in the main code, and disable the timer when I see that the flag is set. I would like to disable the timer, without having to continuously checking the status of a flag.

Code: [Select all] [Expand/Collapse]

1. hw_timer_t * timer = NULL;
2. int counter = 10;
3.  
4. void setup() {
5.   Serial.begin(115200);
6.    
7.   timer = timerBegin(2, 80, true);
8.   timerAttachInterrupt(timer, &onTimer, true);
9.   timerAlarmWrite(timer, 500000, true);  // Interrupt occurs every 500ms
10.   timerAlarmEnable(timer);
11. }
12.  
13. void loop() {
14.   Serial.println(counter);
15.   delay(100);
16. }
17.  
18. void onTimer() {
19.   if (counter == 0) {
20.     timerAlarmDisable(timer);
21.   } else {
22.     counter = counter - 1;
23.   }
24. }

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This code works...

Code: [Select all] [Expand/Collapse]

1. hw_timer_t * timer = NULL;
2. int counter = 10;
3. boolean timer_off_flag = false;
4.  
5. void setup() {
6.   Serial.begin(115200);
7.    
8.   timer = timerBegin(2, 80, true);
9.   timerAttachInterrupt(timer, &onTimer, true);
10.   timerAlarmWrite(timer, 500000, true);  // Interrupt occurs every 500ms
11.   timerAlarmEnable(timer);
12. }
13.  
14. void loop() {
15.   Serial.println(counter);
16.  
17.   if (timer_off_flag == true) {
18.     timerAlarmDisable(timer);
19.     timer_off_flag = false;
20.   }
21.   delay(100);
22. }
23.  
24. void onTimer() {
25.   if (counter == 0) {
26.     timer_off_flag = true;
27.   } else {
28.     counter = counter - 1;
29.   }
30. }

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