Issue of disconnection within 1 minute with iPad Pro (A1673)

[saka4849]

Flash nRF5_SDK_15.2.0 ble_app_uart in PCA10056 without editing,
It occurs regardless of iOS Apps (nRF Connect / nRF Toolbox / LightBlue) when connected with iPad (A1673 iOS13.2).
It does not occur on iPad Air2 (A1566 iOS13.2) or iPad Pro3 (A1876).

It occurs even if sd_ble_gap_disconnect in project is commented out.
There is no error in Sniffer. (File reference)

Interval Max * (Slave Latency + 1) ≤ 2 seconds
Interval Min ≥ 20 ms
Interval Min + 20 ms ≤ Interval Max
Slave Latency ≤ 4
connSupervisionTimeout ≤ 6 seconds
Interval Max * (Slave Latency + 1) * 3 < connSupervisionTimeout

I follow these Apple guidelines.

• SLAVE_LATENCY：0
• connSupervisionTimeout：4s
• Interval Min：20ms
• Interval Max：75ms
• FIRST_CONN_PARAMS_UPDATE_DELAY：5000ms
• NEXT_CONN_PARAMS_UPDATE_DELAY：30000ms

Please help me with your advice...

SDK:nRF5_SDK_15.2.0
SD:s140_nrf52_6.1.0_softdevice.hex

cap.pcapng　

[Simon]

I am sorry for the delay, I am currently looking into your issue and will try to provide you with an answer as soon as possible.

Best regards,

Simon

[saka4849]

Thank You Simon!! I got it.
I'm looking forward to your reply.

Thanks and Best regards.

saka

[Simon]

Could you try to debug your nRF52840_PCA10056 and figure out what is failing? What function is failing and what error does it return?

Best regards,

Simon

[saka4849]

I did not get any error...

<info> app: Debug logging for UART over RTT started.
<info> app: Connected
<info> app: Data len is set to 0xB6(182)
<info> app: Disconnected

Thanks and Best regards.

saka

[Simon]

In the sniffer trace, it seems like the error happens on the peripheral/slave (ble_app_uart) side, since the SLAVE all the sudden stops sending messages. In the main.c file of ble_app_uart inside ble_evt_handler() in the case BLE_GAP_EVT_DISCONNECTED, try printing out:

p_ble_evt->evt.gap_evt.params.disconnected.reason

Then you can see the reason for the disconnect.

Best regards,

Simon

[saka4849]

I confirmed it was 0x22 (BLE_HCI_STATUS_CODE_LMP_RESPONSE_TIMEOUT?).
What does this mean?