When I use sd_ble_gap_adv_start( ), sometimes get return value NRF_ERROR_BUSY . What's the meaning of this error No. ?
Maybe you trying to call sd_ble_gap_adv_start() when you already advertising and get this error?
If I don't call sd_ble_gap_adv_stop() before sd_ble_gap_adv_start(), the error_code become NRF_ERROR_INVALID_STATE