5240 SDK V14.2.0 Bluetooth reconnect failure

[davidb]

I have a BT app on an IPad. I can connect to the the 52840 dev board  fine. I tell the iPad app to disconnect and it does.

nRF52840 dev board disconnects. When I try to connect to the dev board from the iPad app again the connection fails to complete.

I don't see BLE_GAP_EVT_CONN_PARAM_UPDATE event message during the second connection attempt.

I also don't see AMT_EVT_NOTIF_ENABLED type of message.

I don't know BT so debugging this is a bit new to me.

Thanks.

[Sigurd]

Hi,

When I try to connect to the dev board from the iPad app again the connection fails to complete.

1) Does the nRF52840 advertise when you try to connect the second time?

2) Do you see the same issue with nRF Connect app? https://www.nordicsemi.com/Products/Development-tools/nrf-connect-for-mobile

Any errors code when you try to connect?

3) 

I don't see BLE_GAP_EVT_CONN_PARAM_UPDATE event message during the second connection attempt.

Do you get BLE_GAP_EVT_CONNECTED ?

[davidb]

Question 1:

After disconnect is received by nRF52840 we call gap_params_init(), gatt_init(), advertising_data_set(), sd_ble_gap_adv_start(),

bsp_indication_set(BSP_INDICATE_ADVERTISING);

I think this should be good.

Question 2:

Using nRF Connect app on Android I cannot connect a second time. When I try to connect Connect app displays

"Error 133 (0x85): GATT_ERROR"

There are no indications on the 52840 device for this connection attempt.

Question 3:

On 52840 device  BLE_GAP_EVT_CONNECTED event is received on first connection. When attempting a second connection using iPad app  BLE_GAP_EVT_CONNECTED is received but no other events.

Sample Log:

<debug> app: PHY update request.
<debug> nrf_ble_gatt: Data length updated to 251 on connection 0x1.
<debug> nrf_ble_gatt: max_rx_octets: 251
<debug> nrf_ble_gatt: max_tx_octets: 251
<debug> nrf_ble_gatt: max_rx_time: 2120
<debug> nrf_ble_gatt: max_tx_time: 2120
<info> app: Data length updated to 251 bytes.
<debug> nrf_ble_gatt: Data length updated to 251 on connection 0x1.
<debug> nrf_ble_gatt: max_rx_octets: 251
<debug> nrf_ble_gatt: max_tx_octets: 251
<debug> nrf_ble_gatt: max_rx_time: 2120
<info> app: ATT MTU exchange completed. MTU set to 247 bytes.
<debug> app: _evt_handler Event: (0x00)
<info> app: Notifications enabled. 0x00
<debug> app: CONNECTED
<info> app: Connection interval updated: 144, 144.
<debug> app: _evt_handler Event: (0x03)
<info> app: AMT_EVT_TRANSFER_FINISHED. 0x03
<debug> app: Disconnected: reason 0x13.  <<<<<< DISCONNECT at this point

Reconnect from iPad app:

<debug> nrf_ble_gatt: Requesting to update ATT MTU to 247 bytes on connection 0x1.
<debug> nrf_ble_gatt: Updating data length to 251 on connection 0x1.
<debug> app: ++++ Connected

<debug> app: PHY update request.
<debug> nrf_ble_gatt: Data length updated to 251 on connection 0x1.
<debug> nrf_ble_gatt: max_rx_octets: 251
<debug> nrf_ble_gatt: max_tx_octets: 251
<debug> nrf_ble_gatt: max_rx_time: 2120
<debug> nrf_ble_gatt: max_tx_time: 2120
<info> app: Data length updated to 251 bytes.
<debug> nrf_ble_gatt: Data length updated to 251 on connection 0x1.
<debug> nrf_ble_gatt: max_rx_octets: 251
<debug> nrf_ble_gatt: max_tx_octets: 251
<debug> nrf_ble_gatt: max_rx_time: 2120
<info> app: ATT MTU exchange completed. MTU set to 247 bytes.

No other log output

[davidb]

I found that the issue is with our application and not sdk code. We will resolve this internally.

Thanks.