nrf52840 , android disconnect after 28 seconds of connection

[Judge]

hi ,

I have a project with sdk14.2 nrf52832. It works well, it can broadcast, it can connect, everything is fine.

But I have a new project that requires nrf52840. My chip is 52840 QIAAC0. It only supports sdk15.0.

So I first tried to change the original project to NRF52840, which supports sdk15.0.

The transplant went well, broadcasting on 52840. But something strange happens when I connect to my phone.

It will disconnect after about 25 seconds. But it's the mobile phone that's actively disconnected. And 52840 re-enter broadcast mode.

I get the logger from sniffer.I found out that BLE's communication with mobile phones suddenly stopped. 

There was no communication for ten seconds, so the phone was disconnected.

I don't know why . Can you analyze the problem? how to solve problem?

sr3 lmp disconnet log01.pcapng

BR

Judge

[Martin Lesund]

Hi Judge,

With what exactly phone are you experiencing this with?

What Softdevice version are you running on your device?

Is this a custom firmware made from scratch or is it based on a particular example in the SDK?

Do you get any logging information out of the peripheral?

(Have you followed the Softdevice migration guide?)

[Judge]

hi 

My phone's android is 8.1.0, support bluetooth 5.

The SDK I'm using now is 15.0. Softdevice is s140_nrf52_6.0.0_softdevice.

I used the Smart Remote 3 program(SR3 version 1.2) to migrate to 52840.

Nothing logger.Maybe I didn't open more debug information.

I have followed the instructions in the migration manual.

I have solved the problem. Add the following code in the sofedevice BLE event:

        case BLE_GAP_EVT_PHY_UPDATE_REQUEST:

        {

            NRF_LOG_DEBUG("PHY update request.");

            ble_gap_phys_t const phys =

            {

                .rx_phys = BLE_GAP_PHY_AUTO,

                .tx_phys = BLE_GAP_PHY_AUTO,

            };

            err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);

            APP_ERROR_CHECK(err_code);

        } break;

I don't know why ?

[Martin Lesund]

Hi Judge,

So if I understand you correctly you have solved the issue?

but you are wondering why it now works?

 

I do not know what your code looked like before, but the way you are handling the BLE_GAP_EVT_PHY_UPDATE_REQUEST case is the same as it is done in "ble_app_uart" example. Which is to automatically choose the PHYs the peer prefers to use. 

 

 

[Judge]

hi Martin Lesund,

Yes, I did. The problem solved.

Thank you!