nRF52840DK can not re-connect Windows OS bluetooh

[Eason Peng]

Hi,

I have a nRF52840DK for evaluating the connection between nRF52840 and Windows 11 tablet.

The situation is like this:

The DK acts as a peripheral device and always power on, waiting for the tablet connection request. When the tablet powers on, the Qt BLE software searches the bluetooth list and find the DK. The tablet connects and DK board correctly. 

However, when the tablet disconnects the BLE connection with DK board and tries to connect again, the Qt software can find the DK but not connect to it. 

After shutting down the tablet bluetooth by Windows OS functionality and trying again, it can connect again.

In addition, I used the Windows Laptop. The situation is the same.

By the way, when I use nRF Connect IOS App to connect the DK board, it works fine.

The environment setup:

DK:

  - SDK: ncs 2.4.0,

  - Config file:

# --------------------------------------------- #
#                Default Setting                #
#                                               #
#                                               #
# --------------------------------------------- #

# Enable the UART driver
CONFIG_UART_ASYNC_API=y
CONFIG_NRFX_UARTE0=y
CONFIG_SERIAL=y

CONFIG_GPIO=y

# Make sure printk is printing to the UART console
CONFIG_CONSOLE=y
CONFIG_UART_CONSOLE=y

CONFIG_HEAP_MEM_POOL_SIZE=2048

CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME="MY_CTR"
# CONFIG_BT_DEVICE_APPEARANCE=833
CONFIG_BT_MAX_CONN=1
CONFIG_BT_MAX_PAIRED=1
CONFIG_BT_GATT_CLIENT=y

# # Enable the NUS service
# CONFIG_BT_NUS=y
CONFIG_BT_NUS_UART_BUFFER_SIZE=100

# # Enable bonding
# CONFIG_BT_SETTINGS=y
# CONFIG_FLASH=y
# CONFIG_FLASH_PAGE_LAYOUT=y
# CONFIG_FLASH_MAP=y
# CONFIG_NVS=y
CONFIG_SETTINGS=y

# Enable DK LED and Buttons library
CONFIG_DK_LIBRARY=y

# # This example requires more workqueue stack
CONFIG_INIT_STACKS=y
CONFIG_THREAD_STACK_INFO=y
CONFIG_MAIN_STACK_SIZE=4096
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=4096
CONFIG_BT_RX_STACK_SIZE=4096

# Config logger
CONFIG_LOG=y
# CONFIG_USE_SEGGER_RTT=y
# CONFIG_LOG_BACKEND_RTT=y
# CONFIG_LOG_BACKEND_UART=n
# CONFIG_LOG_PRINTK=n

# CONFIG_ASSERT=y

# --------------------------------------------- #
#                Custom Setting                 #
#                                               #
#                                               #
# --------------------------------------------- #
# CJSON
CONFIG_CJSON_LIB=y
CONFIG_NEWLIB_LIBC=y
CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y

# Enable PWM
CONFIG_PWM=y
CONFIG_PWM_LOG_LEVEL_DBG=y
CONFIG_PWM_NRF5_SW=y
CONFIG_PWM_NRFX=y

# Enable Random Number
CONFIG_HARDWARE_DEVICE_CS_GENERATOR=y

Tablet:

 - Windows 11 Pro,

 - Software: Qt 5.15.2

 - LMP 10.19 ( BLE 5.1)

Laptop:

 - Windows 11 Pro,

 - Software: Qt 5.15.2

 - LMP 11.8 ( BLE 5.2)

I am trying to know why the behavior is so strange in this case. 

[Einar Thorsrud]

Hi,

Based on what you describe it helps rebooting the tablet, so the nRF itself is not the reason. I don't know what is happenign on the Windows side, but you could make a sniffer trace of the working and non-working case to see the difference. After that you would have to look into your Windows side Bluetooth application to understand what it behaves the way it does.

[Eason Peng]

Many thanks for your reply. I will use Nordic sniffer to trace the data packet and discuss with you later.

Here is another question cuz I am a beginner of nRF52. Does the Nordic sniffer detect all kinds of BLE packet for  windows tablets and other PC? If yes, is there any tutorial to filter the data packet?

One more thing, I used another PC with LMP 12.13820 (BLE 5.3). The DK works fine with PC.

[Einar Thorsrud]

Hi

The nRF Sniffer will either receive advertising packets, or follow a connection. To do the latter, you select that you want to follow an advertiser, and the sniffer will follow the connection if it sees a CONNECT_IND. It can only follow a single connection. See Common sniffing actions for more.