[Docs] Timer API documentation

cores/esp32/esp32-hal-timer.h

@@ -58,7 +58,7 @@ bool timerGetAutoReload(hw_timer_t *timer);
 
 void timerAlarmEnable(hw_timer_t *timer);
 void timerAlarmDisable(hw_timer_t *timer);
-void timerAlarmWrite(hw_timer_t *timer, uint64_t interruptAt, bool autoreload);
+void timerAlarmWrite(hw_timer_t *timer, uint64_t alarm_value, bool autoreload);
 
 bool timerAlarmEnabled(hw_timer_t *timer);
 uint64_t timerAlarmRead(hw_timer_t *timer);

docs/source/api/timer.rst

@@ -0,0 +1,377 @@
+##########
+Timer
+##########
+
+About
+-----
+
+The ESP32 SoCs contains from 2 to 4 hardware timers. 
+They are all 64-bit (54-bit for ESP32-C3) generic timers based on 16-bit pre-scalers and 64-bit (54-bit for ESP32-C3) 
+up / down counters which are capable of being auto-reloaded.
+
+========= ================
+ESP32 SoC Number of timers
+========= ================
+ESP32     4
+ESP32-S2  4
+ESP32-C3  2
+ESP32-S3  4
+========= ================
+
+Arduino-ESP32 Timer API
+----------------------------
+
+timerBegin
+**********
+
+This function is used to configure the timer. After successful setup the timer will automatically start.
+
+.. code-block:: arduino
+
+    hw_timer_t * timerBegin(uint8_t num, uint16_t divider, bool countUp);
+
+* ``num`` select timer number.
+* ``divider`` select timer divider.
+* ``resolution`` select timer resolution.
+
+  * range is 1-14 bits (1-20 bits for ESP32).
+
+This function will return ``timer`` structure if configuration is successful.
+If ``NULL`` is returned, error occurs and the timer was not configured.
+
+timerEnd
+********
+
+This function is used to end timer.
+
+.. code-block:: arduino
+
+    void timerEnd(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+timerSetConfig
+**************
+
+This function is used to configure initialized timer (timerBegin() called).
+
+.. code-block:: arduino
+
+    uint32_t timerGetConfig(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``configuration`` as uint32_t number. 
+This can be translated by inserting it to struct ``timer_cfg_t.val``.
+
+timerAttachInterrupt
+********************
+
+This function is used to attach interrupt to timer.
+
+.. code-block:: arduino
+
+    void timerAttachInterrupt(hw_timer_t *timer, void (*fn)(void), bool edge);
+
+* ``timer`` timer struct.
+* ``fn`` funtion to be called when interrupt is triggered.
+* ``edge`` select edge to trigger interrupt (only LEVEL trigger is currently supported).
+
+timerDetachInterrupt
+********************
+
+This function is used to detach interrupt from timer.
+
+.. code-block:: arduino
+
+    void timerDetachInterrupt(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+timerStart
+**********
+
+This function is used to start counter of the timer.
+
+.. code-block:: arduino
+
+    void timerStart(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+timerStop
+*********
+
+This function is used to stop counter of the timer.
+
+.. code-block:: arduino
+
+    void timerStop(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+timerRestart
+************
+
+This function is used to restart counter of the timer.
+
+.. code-block:: arduino
+
+    void timerRestart(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+timerWrite
+**********
+
+This function is used to set counter value of the timer.
+
+.. code-block:: arduino
+
+    void timerWrite(hw_timer_t *timer, uint64_t val);
+
+* ``timer`` timer struct.
+* ``val`` counter value to be set.
+
+timerSetDivider
+***************
+
+This function is used to set the divider of the timer.
+
+.. code-block:: arduino
+
+    void timerSetDivider(hw_timer_t *timer, uint16_t divider);
+
+* ``timer`` timer struct.
+* ``divider`` divider to be set.
+
+timerSetCountUp
+***************
+
+This function is used to configure counting direction of the timer.
+
+.. code-block:: arduino
+
+    void timerSetCountUp(hw_timer_t *timer, bool countUp);
+
+* ``timer`` timer struct.
+* ``countUp`` select counting direction (``true`` = increment).
+
+timerSetAutoReload
+******************
+
+This function is used to set counter value of the timer.
+
+.. code-block:: arduino
+
+    void timerSetAutoReload(hw_timer_t *timer, bool autoreload);
+
+* ``timer`` timer struct.
+* ``autoreload`` select autoreload (``true`` = enabled).
+
+timerStarted
+************
+
+This function is used to get if the timer is running.
+
+.. code-block:: arduino
+
+    bool timerStarted(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``true`` if the timer is running. If ``false`` is returned, timer is stopped.
+
+timerRead
+*********
+
+This function is used to read counter value of the timer.
+
+.. code-block:: arduino
+
+    uint64_t timerRead(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``counter value`` of the timer.
+
+timerReadMicros
+***************
+
+This function is used to read counter value in microseconds of the timer.
+
+.. code-block:: arduino
+
+    uint64_t timerReadMicros(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``counter value`` of the timer in microseconds.
+
+timerReadMilis
+**************
+
+This function is used to read counter value in miliseconds of the timer.
+
+.. code-block:: arduino
+
+    uint64_t timerReadMilis(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``counter value`` of the timer in miliseconds.
+
+timerReadSeconds
+****************
+
+This function is used to read counter value in seconds of the timer.
+
+.. code-block:: arduino
+
+    double timerReadSeconds(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``counter value`` of the timer in seconds.
+
+timerGetDivider
+***************
+
+This function is used to get divider of the timer.
+
+.. code-block:: arduino
+
+    uint16_t timerGetDivider(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``divider`` of the timer.
+
+timerGetCountUp
+***************
+
+This function is used get counting direction of the timer.
+
+.. code-block:: arduino
+
+    bool timerGetCountUp(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``true`` if the timer counting direction is UP (incrementing).
+If ``false`` returned, the timer counting direction is DOWN (decrementing).
+
+timerGetAutoReload
+******************
+
+This function is used to get configuration of auto reload of the timer.
+
+.. code-block:: arduino
+
+    bool timerGetAutoReload(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``true`` if the timer auto reload is enabled.
+If ``false`` returned, the timer auto reload is disabled.
+
+timerAlarmEnable
+****************
+
+This function is used to enable generation of timer alarm events.
+
+.. code-block:: arduino
+
+    void timerAlarmEnable(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+timerAlarmDisable
+*****************
+
+This function is used to disable generation of timer alarm events.
+
+.. code-block:: arduino
+
+    void timerAlarmDisable(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+timerAlarmWrite
+***************
+
+This function is used to configure alarm value and autoreload of the timer.
+
+.. code-block:: arduino
+
+    void timerAlarmWrite(hw_timer_t *timer, uint64_t alarm_value, bool autoreload);
+
+* ``timer`` timer struct.
+* ``alarm_value`` alarm value to generate event.
+* ``autoreload`` enabled/disabled autorealod.
+
+timerAlarmEnabled
+*****************
+
+This function is used to get status of timer alarm.
+
+.. code-block:: arduino
+
+    bool timerAlarmEnabled(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``true`` if the timer alarm is enabled.
+If ``false`` returned, the timer alarm is disabled.
+
+timerAlarmRead
+**************
+
+This function is used to read alarm value of the timer.
+
+.. code-block:: arduino
+
+    uint64_t timerAlarmRead(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+timerAlarmReadMicros
+********************
+
+This function is used to read alarm value of the timer in microseconds.
+
+.. code-block:: arduino
+
+    uint64_t timerAlarmReadMicros(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``alarm value`` of the timer in microseconds.
+
+timerAlarmReadSeconds
+*********************
+
+This function is used to read alarm value of the timer in seconds.
+
+.. code-block:: arduino
+
+    double timerAlarmReadSeconds(hw_timer_t *timer);
+
+* ``timer`` timer struct.
+
+This function will return ``alarm value`` of the timer in seconds.
+
+Example Applications
+********************
+
+There are 2 examples uses of Timer:
+
+Repeat timer example:
+
+.. literalinclude:: ../../../libraries/ESP32/examples/Timer/RepeatTimer/RepeatTimer.ino
+    :language: arduino
+
+Watchdog timer example:
+
+.. literalinclude:: ../../../libraries/ESP32/examples/Timer/WatchdogTimer/WatchdogTimer.ino
+    :language: arduino