Connection to Android isn't stable

RE: Connection to Android isn't stable

Ole Morten — Mon, 31 Mar 2014 09:54:00 GMT

Take a look at this question: https://devzone.nordicsemi.com/index.php/what-is-connection-parameters

If the Central for some reason rejects the parameters you request, you will get this error back. To fix it, you must therefore try to request other parameters.

However, I think my first reply answered the original question, so to clear up this question, I'd be happy if you could click the "Accept as answer" button below it. If you have any further problems, I suggest you post them separately, to keep each question here as focused as possible.

RE: Connection to Android isn't stable

Jeremy Hubbard — Fri, 28 Mar 2014 16:48:02 GMT

It looks like the error thrown as seen using the sniffer is Error code: Unacceptable Connection Interval (0x3b). I am seeing that the error event BLE_CONN_PARAMS_EVT_FAILED being called in the debugger. I am using the Android Master Control Panel app when I see this error. I am only sending notifications in my program in the nRF51822, what could be causing that error?

Thanks, Jeremy

RE: Connection to Android isn't stable

Ole Morten — Fri, 28 Mar 2014 10:51:20 GMT

Have you tried using the sniffer to see what happens on-air? https://www.nordicsemi.com/eng/content/download/39099/660783/file/ble-sniffer_win_0.9.5.zip

Also, what is the reason when you get the DISCONNECTED event on the nRF51 side? You should also check that it isn't a connection parameter update that's failing, i.e. that you're asking for parameters that the Android device doesn't accept. If so, you'll see on_conn_params_evt() being called with evt_type BLE_CONN_PARAMS_EVT_FAILED. Do you see this when running with a debugger?

RE: Connection to Android isn't stable

Jeremy Hubbard — Tue, 25 Mar 2014 16:04:26 GMT

I have already updated the TWI driver to be softdevice compatible and I can transmit to a computer just fine. I'm not seeing hard faults.

Based on the 0x3401 error thread, I modified the error checking after the ble_lbs_data_send() command to:

err_code = ble_lbs_data_send(&m_lbs, data);
if (err_code != BLE_ERROR_GATTS_SYS_ATTR_MISSING 
        && err_code != NRF_SUCCESS 
        && err_code != BLE_ERROR_INVALID_CONN_HANDLE 
        && err_code != NRF_ERROR_INVALID_STATE 
        && err_code != BLE_ERROR_NO_TX_BUFFERS)
{
    APP_ERROR_CHECK(err_code);
}

and now I can transmit data, but after the connection is established with the Android device it disconnects every 16.5 seconds, like clockwork. Any ideas?

Thanks, Jeremy

RE: Connection to Android isn't stable

Ole Morten — Fri, 21 Mar 2014 16:45:35 GMT

You can read about the 0x3401 error in this question.

If you're working with TWI sensors, could it be that you have not fixed your TWI module to be softdevice compatible? If so, you'll see HardFaults when if the module tries to access the softdevice directly, but this should be fairly easy to see with a debugger, by letting the chip run freely and then halt when the connection is lost. You may have use in taking a look at this question, and this GitHub example, the latter if you're using a second revision chip (FA or later for QFN).