Hello everyone,
I’m currently developing firmware on our custom board based on the nRF52840, using nRF Connect SDK v3.0.0 and Visual Studio Code.
The board is designed to communicate over BLE/GATT with our proprietary Android app (tested on Android 13 and 14).
The problem I’m facing is the following:
The first time I try to connect from our Android app — typically right after a phone reboot or after toggling Bluetooth off and on — the connection does not succeed (the app just stays in a waiting state).
However, if I then launch another app that scans for BLE devices (without even connecting), such as the nRF Connect app, and then close it, from that moment on our app can connect and reconnect without issues.
This issue does not happen when I flash our "old" firmware, which was developed in the Arduino environment using ArduinoBLE and mbed.
In that case, the app is able to connect immediately, under all conditions.
We are currently porting our firmware from Arduino to nRF Connect, so understanding this difference is critical.
I’ve tried multiple approaches but haven’t been able to resolve the issue.
Some observations:
-
The firmware using nRF Connect advertises a MAC address:
EA:5A:98:E2:7A:32(random static) -
The firmware using ArduinoBLE advertises a MAC address:
6A:5A:98:E2:7A:32(public) -
Using Wireshark, the ADV_IND packets differ mainly because of this
I’m attaching the prj.conf file.
# Abilita il logging di Zephyr CONFIG_LOG=n # Imposta il livello di log di default (3 per DBG, 2 for INF, 1 for WRN, 0 for ERR) CONFIG_LOG_DEFAULT_LEVEL=3 # Usa il backend UART per i log (se vuoi visualizzarli su console seriale) CONFIG_LOG_BACKEND_UART=n # Se preferisci usare il console standard, puoi anche abilitare: CONFIG_STDOUT_CONSOLE=n CONFIG_GPIO=y # Abilita printk CONFIG_PRINTK=y # abilita console CONFIG_CONSOLE=y # Abilita la console UART CONFIG_UART_CONSOLE=y CONFIG_STDOUT_CONSOLE=n # Abilita console RTT CONFIG_USE_SEGGER_RTT=n CONFIG_LOG_BACKEND_RTT=n # Configura la seriale CONFIG_SERIAL=y # Abilita il logging per il sottosistema Bluetooth CONFIG_BT_LOG_LEVEL_WRN=n CONFIG_MAIN_STACK_SIZE=4096 # Floating Point Unit CONFIG_FPU=y ################################################################################ # Bluetooth LE ################################################################################ CONFIG_BT=y CONFIG_BT_SMP=y CONFIG_BT_BONDABLE=n CONFIG_BT_CENTRAL=n CONFIG_BT_PERIPHERAL=y CONFIG_BT_GATT_CLIENT=y CONFIG_BT_FIXED_PASSKEY=n CONFIG_BT_FILTER_ACCEPT_LIST=n CONFIG_SETTINGS=n CONFIG_BT_PRIVACY=n CONFIG_BT_ID_MAX=1 # Numero massimo di connessioni: per periferica, solitamente 1 CONFIG_BT_MAX_CONN=1 # Increase stack size for the main thread and System Workqueue CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048 CONFIG_MAIN_STACK_SIZE=2048 # Configure your preferred connection parameters CONFIG_BT_PERIPHERAL_PREF_MIN_INT=20 CONFIG_BT_PERIPHERAL_PREF_MAX_INT=35 CONFIG_BT_PERIPHERAL_PREF_LATENCY=0 # Timeout in milliseconds (un valore basso favorisce la rapidità di connessione ma potrebbe renderla instabile in ambienti rumorosi, # quindi tra 100 (rapida) e 500 (stabile) (il default sarebbe 42) (non deve essere inferiore a (1 + latency) * max_int * 2)) CONFIG_BT_PERIPHERAL_PREF_TIMEOUT=75 #CONFIG_BT_GAP_AUTO_UPDATE_CONN_PARAMS=y # Update Data Length and MTU CONFIG_BT_USER_DATA_LEN_UPDATE=y CONFIG_BT_CTLR_DATA_LENGTH_MAX=251 CONFIG_BT_BUF_ACL_RX_SIZE=251 CONFIG_BT_BUF_ACL_TX_SIZE=251 CONFIG_BT_L2CAP_TX_MTU=247 # BT nome dispositivo CONFIG_BT_DEVICE_NAME="LACS-DEVICE C.U." CONFIG_BT_DEVICE_NAME_DYNAMIC=y # Enable PHY updates. CONFIG_BT_USER_PHY_UPDATE=y # enable adv extended CONFIG_BT_EXT_ADV=n ################################################################################# # Use the c++ compiler CONFIG_CPP=y # Abilita il supporto per l'ADC CONFIG_ADC=y # Abilita il supporto per il driver ADC specifico della piattaforma (nRF SAADC per nRF52840) CONFIG_ADC_NRFX_SAADC=y CONFIG_NRFX_SAADC=y # gestione NFC CONFIG_NCS_SAMPLES_DEFAULTS=y CONFIG_REBOOT=y CONFIG_DK_LIBRARY=y CONFIG_NFC_T2T_NRFXLIB=y CONFIG_NFC_NDEF=y CONFIG_NFC_NDEF_MSG=y CONFIG_NFC_NDEF_RECORD=y CONFIG_NFC_NDEF_TEXT_RECORD=y # Abilitare ASSERT solo in modalità debug. Queste aumentano dimensioni e consumo di energia. in modalità release, non sono necessarie. CONFIG_ASSERT=n CONFIG_FLASH=y CONFIG_FLASH_PAGE_LAYOUT=y CONFIG_COUNTER=y # TIMER 1 per gestione timer di scansione pin sensori per ricezione IR (il timer 0 non funziona probabilmente già usato da altro) CONFIG_NRFX_TIMER3=y # --- build outputs --- CONFIG_BUILD_OUTPUT_BIN=y CONFIG_KERNEL_BIN_NAME="micro_nrfc_cu" # opzionale: cambia nome file finale ################################################################################# # Enable FOTA over Bluetooth LE CONFIG_NCS_SAMPLE_MCUMGR_BT_OTA_DFU=y
Feel free to ask for any additional details about the firmware, advertising structure, or Wireshark trace.
Thanks in advance!
Best regards,
Paolo
