Advertising and sleep

[dmleone]

I tried searching for this response but cant find exact answer

SDK15.2 and API6.1

I am trying to have an advertiser but would like to put it in some sleep mode and advertise. if i do sd_power_system_off() it turns off until i hit the wake GPIO. I tried using sd_app_evt_wait(), however that too doe snot seem to allow me to advertise and sleep at the same time.

What is recommended call to put the thing to sleep but be able to wake on ble event when the scanner tries to connect.

[Jørgen Holmefjord]

Hi,

It is not possible to advertise when you are in deep sleep. In system off mode, all clock sources will be turned off, and you will only be able to wake on certain peripherals (reset, GPIO, NFCT, LPCOMP).

It is also not possible to "advertise and sleep at the same time". You can enter system on idle mode between advertising events, but the chip will wake up to process and prepare advertising, as the CPU is required to start the advertising and setup buffers, etc.

Running sd_app_evt_wait() in the main-loop is the correct way to enter lowest possible sleep mode while doing advertising and receive connection events.

Best regards,
Jørgen

[dmleone]

Do i have to call sd_app_evt_wait() after each time i send advertising? or if during the BLE_GAP_EVT_DISCONNECTED call i do the following, would it go into semi sleep advertising cycles? or do i need to put it in the idle_state_handle()?

case BLE_GAP_EVT_DISCONNECTED:
            m_conn_handle = BLE_CONN_HANDLE_INVALID;
            
            err_code = sd_app_evt_wait();
            APP_ERROR_CHECK(err_code);

            advertising_start(false);
            break;