I'm facing a rather strange problem with an nRF52832 board I'm developing for. I'm using SDK 15.2 and S132 v6.0.0.
Sometimes, during the connection/negotiation phase, my device seems to get stuck in a weird state and can't send notifications. I've examined my logs and found out that when it works, I receive BLE_GATTC_EVT_EXCHANGE_MTU_RSP, and when it gets stuck, there is no such event received.
This is an example of a failed connection attempt:
<info> app: BLE_GAP_EVT_CONNECTED, conn handle: 1, role: 1 <debug> app: max_conn_interval: 11 ms <debug> app: min_conn_interval: 11 ms <debug> app: slave_latency: 0 connection events <debug> app: conn_sup_timeout: 2000 ms <debug> nrf_ble_gatt: Data length updated to 64 on connection 0x1. <debug> nrf_ble_gatt: max_rx_octets: 64 <debug> nrf_ble_gatt: max_tx_octets: 64 <debug> nrf_ble_gatt: max_rx_time: 2120 <debug> nrf_ble_gatt: max_tx_time: 2120 <debug> app: BLE EVENT: 0x0024 <debug> nrf_ble_gatt: Peer on connection 0x1 requested an ATT MTU of 515 bytes. <debug> nrf_ble_gatt: Updating ATT MTU to 64 bytes (desired: 64) on connection 0x1. <debug> app: BLE EVENT: 0x0055 <debug> app: BLE EVENT: 0x0050 <debug> app: BLE_GATTS_EVT_WRITE, handle: 0x0017, len: 2 <error> app: Failed to notify, error: NRF_ERROR_INVALID_STATE (0x0008)
The central I'm connecting to is a Mac. This happens in the logs on the central:
default 12:11:12.512164+0000 bluetoothd Sending MTU Request - MTU:515 Transport:2 default 12:11:12.555573+0000 bluetoothd Received MTU Response - Response:64 Requested:515 Transport:2
This is an example of a successful attempt:
<info> app: BLE_GAP_EVT_CONNECTED, conn handle: 1, role: 1 <debug> app: max_conn_interval: 11 ms <debug> app: min_conn_interval: 11 ms <debug> app: slave_latency: 0 connection events <debug> app: conn_sup_timeout: 2000 ms <debug> nrf_ble_gatt: Data length updated to 64 on connection 0x1. <debug> nrf_ble_gatt: max_rx_octets: 64 <debug> nrf_ble_gatt: max_tx_octets: 64 <debug> nrf_ble_gatt: max_rx_time: 2120 <debug> nrf_ble_gatt: max_tx_time: 2120 <debug> app: BLE EVENT: 0x0024 <debug> nrf_ble_gatt: Peer on connection 0x1 requested an ATT MTU of 515 bytes. <debug> nrf_ble_gatt: Updating ATT MTU to 64 bytes (desired: 64) on connection 0x1. <debug> app: BLE EVENT: 0x0055 <debug> nrf_ble_gatt: ATT MTU updated to 64 bytes on connection 0x1 (response). <debug> app: BLE EVENT: 0x003A <debug> app: BLE EVENT: 0x0050
And the central:
default 12:14:35.229238+0000 bluetoothd Sending MTU Request - MTU:515 Transport:2 default 12:14:35.260755+0000 bluetoothd Received MTU Request - MTU:64 Transport:2 default 12:14:35.264938+0000 bluetoothd Received MTU Response - Response:64 Requested:515 Transport:2
Is there anything obvious that could be missing in some parameters/negotiation steps?
