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.

[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