Arduino-esp32: Hardware Timers

[williamhemmingsen]

Are there any examples of hardware timers for Arduino IDE? I have used ESP32 hw timers a lot, but can't make since of them in the ESP32.

I need to sample the adc a a specified rate. I would like to attachinterrupt to and ISR. Here is what I'm doing in the ESP8266. How do I do this in the ESP32?

void timer_init(void) {
timer1_isr_init();
timer1_attachInterrupt(sample_isr);
timer1_enable(TIM_DIV1, TIM_EDGE, TIM_LOOP);
timer1_write(8333); //9600 samples/s
}

void ICACHE_RAM_ATTR sample_isr() {
...do some stuff
}

Thanks!

[me-no-dev]

hw_timer_t * timer = NULL;

void onTimer(){
    Serial.print("timer ");
    Serial.println(millis());
}

// start/stop the timer
void toggleTimer(){
    if(timer){
        timerEnd(timer);
        timer = NULL;
    } else {
        timer = timerBegin(3, 80, 1);//div 80
        timerAttachInterrupt(timer, &onTimer, 1);
        timerAlarmWrite(timer, 1000000, true);//1000ms
        timerAlarmEnable(timer);
    }
}

[arcao]

Edit: @me-no-dev was faster :)

---

There is example which call onTimer every second:

hw_timer_t * timer = NULL;

void onTimer(){
  static unsigned int counter = 1;

  Serial.print("onTimer ");
  Serial.print(counter);
  Serial.print(" at ");
  Serial.print(millis());
  Serial.println(" ms");

  if (counter == 10)
    endTimer();

  counter++;
}

void startTimer() {
  timer = timerBegin(0, 80, true); // timer_id = 0; divider=80; countUp = true;
  timerAttachInterrupt(timer, &onTimer, true); // edge = true
  timerAlarmWrite(timer, 1000000, true);  //1000 ms
  timerAlarmEnable(timer);
}

void endTimer() {
  timerEnd(timer);
  timer = NULL; 
}

void setup() {
  Serial.begin(115200);
  startTimer();
}

void loop() {}

[me-no-dev]

@arcao you asked me as I was looking at the issue :D

[williamhemmingsen]

Thanks Guys, That was perfect. Thanks again for the quick response

[me-no-dev]

:)

[arcao]

BTW I added example: https://github.com/espressif/arduino-esp32/blob/master/libraries/ESP32/examples/Timer/RepeatTimer/RepeatTimer.ino

[williamhemmingsen]

Thanks!  I used your timer example successfully to implement my project.
Thanks again

GitHub - williamhemmingsen/WSPR-ESP32: WSPR implementation using the ESP32 and Si5351

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GitHub - williamhemmingsen/WSPR-ESP32: WSPR implementation using the ESP32 ...
WSPR-ESP32 - WSPR implementation using the ESP32 and Si5351 | |

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  From: Martin Sloup <[email protected]>

To: espressif/arduino-esp32 [e-mail]
Cc: William Hemmingsen ; Author [e-mail]
Sent: Friday, February 17, 2017 7:23 AM
Subject: Re: [espressif/arduino-esp32] Hardware Timers (#214)

There is example which call onTimer every second:hw_timer_t * timer = NULL;

void onTimer(){
static unsigned int counter = 1;

Serial.print("onTimer ");
Serial.print(counter);
Serial.print(" at ");
Serial.print(millis());
Serial.println(" ms");

if (counter == 10)
endTimer();

counter++;
}

void startTimer() {
timer = timerBegin(0, 80, true); // timer_id = 0; divider=80; countUp = true;
timerAttachInterrupt(timer, &onTimer, true); // edge = true
timerAlarmWrite(timer, 1000000, true); //1000 ms
timerAlarmEnable(timer);
}

void endTimer() {
timerEnd(timer);
timer = NULL;
}

void setup() {
Serial.begin(115200);
startTimer();
}

void loop() {}—
You are receiving this because you authored the thread.
Reply to this email directly, view it on GitHub, or mute the thread.

[tobozo]

Your comment is exposing your email address

[me-no-dev]

not anymore :)

[maxpromer]

How to restart timer ? I test by

hw_timer_t * timer = NULL;

void onTimer(){
    Serial.print("timer ");
    Serial.println(millis());
}

// start/stop the timer
void toggleTimer(){
    if(timer){
        timerEnd(timer);
        timer = NULL;
    } else {
        timer = timerBegin(3, 80, 1);//div 80
        timerAttachInterrupt(timer, &onTimer, 1);
        timerAlarmWrite(timer, 100000, true);//1000ms
        timerAlarmEnable(timer);
    }
}

void setup() {
  Serial.begin(115200);
}

void loop() {
  toggleTimer();
  delay(1000);
}

timer not new start.

[XingyumLee]

hw_timer_t * timer = NULL;

void onTimer(){
    Serial.print("timer ");
    Serial.println(millis());
}

// start/stop the timer
void toggleTimer(){
    if(timer){
        timerEnd(timer);
        timer = NULL;
    } else {
        timer = timerBegin(3, 80, 1);//div 80
        timerAttachInterrupt(timer, &onTimer, 1);
        timerAlarmWrite(timer, 1000000, true);//1000ms
        timerAlarmEnable(timer);
    }
}

where to download the lib

[XingyumLee]

Edit: @me-no-dev was faster :)

There is example which call onTimer every second:

hw_timer_t * timer = NULL;

void onTimer(){
  static unsigned int counter = 1;

  Serial.print("onTimer ");
  Serial.print(counter);
  Serial.print(" at ");
  Serial.print(millis());
  Serial.println(" ms");

  if (counter == 10)
    endTimer();

  counter++;
}

void startTimer() {
  timer = timerBegin(0, 80, true); // timer_id = 0; divider=80; countUp = true;
  timerAttachInterrupt(timer, &onTimer, true); // edge = true
  timerAlarmWrite(timer, 1000000, true);  //1000 ms
  timerAlarmEnable(timer);
}

void endTimer() {
  timerEnd(timer);
  timer = NULL; 
}

void setup() {
  Serial.begin(115200);
  startTimer();
}

void loop() {}

so if i end the timer,how can i restart it?

[XingyumLee]

How to restart timer ? I test by

hw_timer_t * timer = NULL;

void onTimer(){
    Serial.print("timer ");
    Serial.println(millis());
}

// start/stop the timer
void toggleTimer(){
    if(timer){
        timerEnd(timer);
        timer = NULL;
    } else {
        timer = timerBegin(3, 80, 1);//div 80
        timerAttachInterrupt(timer, &onTimer, 1);
        timerAlarmWrite(timer, 100000, true);//1000ms
        timerAlarmEnable(timer);
    }
}

void setup() {
  Serial.begin(115200);
}

void loop() {
  toggleTimer();
  delay(1000);
}

timer not new start.

is seems that it just relay for 1 seconds but dont know whether the timer is stopped or not