Wait for idle

include/TheThingsNetwork.h

@@ -615,6 +615,17 @@ class TheThingsNetwork
         ttn_prepare_for_deep_sleep();
     }
 
+    /**
+     * @brief Waits until the TTN device is idle.
+     * 
+     * If the TTN device is idle, the ESP32 can go into deep sleep mode
+     * or be powered off without disrupting an on-going communication.
+     */
+    void waitForIdle()
+    {
+        ttn_wait_for_idle();
+    }
+
     /**
      * @brief Returns the minimum duration the TTN device is busy.
      * 

include/ttn.h

@@ -583,6 +583,14 @@ extern "C"
      */
     void ttn_prepare_for_deep_sleep(void);
 
+    /**
+     * @brief Waits until the TTN device is idle.
+     * 
+     * If the TTN device is idle, the ESP32 can go into deep sleep mode
+     * or be powered off without disrupting an on-going communication.
+     */
+    void ttn_wait_for_idle(void);
+
     /**
      * @brief Returns the minimum duration the TTN device will be busy.
      * 
@@ -599,7 +607,7 @@ extern "C"
      * 
      * @return busy duration (in FreeRTOS ticks)
      */
-    TickType_t ttn_busy_duration();
+    TickType_t ttn_busy_duration(void);
 
     /**
      * @brief Stops all activies.

src/hal/hal_esp32.c

@@ -35,6 +35,7 @@
 
 
 typedef enum {
+    WAIT_KIND_NONE = 0,
     WAIT_KIND_CHECK_IO,
     WAIT_KIND_WAIT_FOR_ANY_EVENT,
     WAIT_KIND_WAIT_FOR_TIMER
@@ -74,6 +75,7 @@ static SemaphoreHandle_t mutex;
 static esp_timer_handle_t timer;
 static int64_t next_alarm;
 static volatile bool run_background_task;
+static volatile wait_kind_e current_wait_kind;
 
 
 // -----------------------------------------------------------------------------
@@ -331,7 +333,9 @@ bool wait(wait_kind_e wait_kind)
     TickType_t ticks_to_wait = wait_kind == WAIT_KIND_CHECK_IO ? 0 : portMAX_DELAY;
     while (true)
     {
+        current_wait_kind = wait_kind;
         uint32_t bits = ulTaskNotifyTake(pdTRUE, ticks_to_wait);
+        current_wait_kind = WAIT_KIND_NONE;
         if (bits == 0)
             return false;
 
@@ -366,6 +370,22 @@ bool wait(wait_kind_e wait_kind)
     }
 }
 
+TickType_t hal_esp32_get_timer_duration(void)
+{
+    wait_kind_e wait_kind = current_wait_kind;
+    int64_t alarm_time = next_alarm;
+
+    if (wait_kind == WAIT_KIND_NONE || wait_kind == WAIT_KIND_CHECK_IO)
+        return 1; // busy, not waiting
+
+    if (alarm_time != 0)
+        return pdMS_TO_TICKS((alarm_time - esp_timer_get_time() + 999) / 1000);
+
+
+    return 0; // waiting indefinitely
+}
+
+
 // Gets current time in LMIC ticks
 u4_t IRAM_ATTR hal_ticks(void)
 {

src/hal/hal_esp32.h

@@ -33,6 +33,8 @@ void hal_esp32_leave_critical_section(void);
 
 void hal_esp32_set_rssi_cal(int8_t rssi_cal);
 
+TickType_t hal_esp32_get_timer_duration(void);
+
 
 #ifdef __cplusplus
 }

src/ttn.c

@@ -305,6 +305,30 @@ bool ttn_is_provisioned(void)
     return ttn_provisioning_have_keys();
 }
 
+void ttn_wait_for_idle(void)
+{
+    while (true)
+    {
+        TickType_t ticks_to_wait = ttn_busy_duration();
+        if (ticks_to_wait == 0)
+            return;
+        vTaskDelay(ticks_to_wait);
+    }
+}
+
+TickType_t ttn_busy_duration(void)
+{
+    TickType_t duration = hal_esp32_get_timer_duration();
+    if (duration != 0)
+        return duration; // busy or timer scheduled
+
+    if (current_rx_tx_window != TTN_WINDOW_IDLE)
+        return pdMS_TO_TICKS(100); // within TX/RX window
+
+    return 0; // idle
+}
+
+
 void ttn_set_rssi_cal(int8_t rssi_cal)
 {
     hal_esp32_set_rssi_cal(rssi_cal);