ESP32 - BLE does not connect/restart after light sleep

Question

noob in arduino here.

I'm trying to connect via BLE after the ESP32 wakeups from light sleep. I have tried many different things, but none of them work. Everything works fine before the device sleeps the first time. Could you guys please give some ideas of what is wrong? the official docs are terrible.

 btStop();
 delay(1000);
 esp_sleep_enable_timer_wakeup(TIME_TO_SLEEP * uS_TO_S_FACTOR);
 Serial.println("Going to light sleep now");
 esp_light_sleep_start();
 btStart();

Answer 1

I finally found the answer, you just need to advertise again the service after it sleeps. First you need to define this:

#if CONFIG_PM_ENABLE
// Configure dynamic frequency scaling:
// maximum and minimum frequencies are set in sdkconfig,
// automatic light sleep is enabled if tickless idle support is enabled.
// esp_pm_config_esp32c3_t pm_config = { // old version
esp_pm_config_t pm_config = {
 .max_freq_mhz = 160, // e.g. 80, 160,
 .min_freq_mhz = 80, // 40
#if CONFIG_FREERTOS_USE_TICKLESS_IDLE
 .light_sleep_enable = true
#endif
 };
ESP_ERROR_CHECK( esp_pm_configure(&pm_config) );
#endif // CONFIG_PM_ENABLE

Then in your loop you could do something like:

esp_sleep_enable_timer_wakeup(TIME_TO_SLEEP * uS_TO_S_FACTOR);
Serial.println("Going to light sleep now");
esp_light_sleep_start();
Serial.println("depois do sleep start");
BLEDevice::startAdvertising();