Hi,
I have a problem understanding the timer example found in the ESP32 arduino core 2.0.14.
The code doesn't say which timer is being used as far as I can see. Here's the code:
/*
Repeat timer example
This example shows how to use hardware timer in ESP32. The timer calls onTimer
function every second. The timer can be stopped with button attached to PIN 0
(IO0).
This example code is in the public domain.
*/
// Stop button is attached to PIN 0 (IO0)
#define BTN_STOP_ALARM 0
hw_timer_t * timer = NULL;
volatile SemaphoreHandle_t timerSemaphore;
portMUX_TYPE timerMux = portMUX_INITIALIZER_UNLOCKED;
volatile uint32_t isrCounter = 0;
volatile uint32_t lastIsrAt = 0;
void ARDUINO_ISR_ATTR onTimer(){
// Increment the counter and set the time of ISR
portENTER_CRITICAL_ISR(&timerMux);
isrCounter = isrCounter + 1;
lastIsrAt = millis();
portEXIT_CRITICAL_ISR(&timerMux);
// Give a semaphore that we can check in the loop
xSemaphoreGiveFromISR(timerSemaphore, NULL);
// It is safe to use digitalRead/Write here if you want to toggle an output
}
void setup() {
Serial.begin(115200);
// Set BTN_STOP_ALARM to input mode
pinMode(BTN_STOP_ALARM, INPUT);
// Create semaphore to inform us when the timer has fired
timerSemaphore = xSemaphoreCreateBinary();
// Set timer frequency to 1Mhz
timer = timerBegin(1000000);
// Attach onTimer function to our timer.
timerAttachInterrupt(timer, &onTimer);
// Set alarm to call onTimer function every second (value in microseconds).
// Repeat the alarm (third parameter) with unlimited count = 0 (fourth parameter).
timerAlarm(timer, 1000000, true, 0);
}
void loop() {
// If Timer has fired
if (xSemaphoreTake(timerSemaphore, 0) == pdTRUE){
uint32_t isrCount = 0, isrTime = 0;
// Read the interrupt count and time
portENTER_CRITICAL(&timerMux);
isrCount = isrCounter;
isrTime = lastIsrAt;
portEXIT_CRITICAL(&timerMux);
// Print it
Serial.print("onTimer no. ");
Serial.print(isrCount);
Serial.print(" at ");
Serial.print(isrTime);
Serial.println(" ms");
}
// If button is pressed
if (digitalRead(BTN_STOP_ALARM) == LOW) {
// If timer is still running
if (timer) {
// Stop and free timer
timerEnd(timer);
timer = NULL;
}
}
}
Am I missing something?
Also. Seems that the timer = timerBegin(1000000); is using frequency, whereas in my code for the older v1.0.8 core I have which timer is being used, the divider, and finally count up or down.
I've looked through the core. Mostly it's above my knowledge level, but can someone please explain.
Main reason for asking is that I have code that compiles and runs on the 1.0.8 core but just keeps resetting on the 2.0.14 core.
For the record I'm using 1.8.16 ide I think.
Any help appreciated
Cheers
Matt