Disconnect after connect parameters update

[Gavin]

Hi, 

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Chip: nRF52832

SDK: nRF5_SDK_17.0.2_d674dde

Role: Central /Peripheral

Project: BLE gateway

===========================

We currently encouter a connect issue with our nrf52832 gateway device, we have no idea about it now...

The ble gateway want to connect the heart rate device, which running the ble_app_hrs example in SDK 17,  for test, but it is disconnected after conn parameters update, the reason is 0x8. From the wireshark, the master has send LL_CONNECTION_UPDATE_IND to slave, but the slave no response any more and enters to adv mode.

I require some support in this. I will appreciate the help given.

Thank you.

[Susheel Nuguru]

The ble gateway want to connect the heart rate device, which running the ble_app_hrs example in SDK 17,  for test, but it is disconnected after conn parameters update, the reason is 0x8. From the wireshark, the master has send LL_CONNECTION_UPDATE_IND to slave, but the slave no response any more and enters to adv mode.

 It is not clear what is happening on the peripheral side since the timestamps are visible in your snapshot. Could it that there is a restart on the peripheral side (mostly APP_ERROR_CHECK)? or could it be a super vision timeout? 

Could it be that your peripheral has some other logic in handling the BLE_GAP_EVT_CONN_PARAM_UPDATE: event and that logic asserted or caused your peripheral to restart?

[Gavin]

Hi Susheel,

It just received BLE_ADV_EVT_FAST...

But now it is stable after setting a smaller conn interval:

#define MIN_CONN_INTERVAL MSEC_TO_UNITS(7.5, UNIT_1_25_MS)
#define MAX_CONN_INTERVAL MSEC_TO_UNITS(30, UNIT_1_25_MS) 

I just confuse why this setting can not work:

#define MIN_CONN_INTERVAL MSEC_TO_UNITS(500, UNIT_1_25_MS)
#define MAX_CONN_INTERVAL MSEC_TO_UNITS(1000, UNIT_1_25_MS) 

Thanks.

[Susheel Nuguru]

With such slow connection interval, it is very easy to lose packets (corrupted) packets in a radio noisy environment. Setting the smaller connection interval with make the exchange of packets faster hence giving more time for retires of packets that are lost/corrupted before the supervision timeout expires.

[Gavin]

Hmm, i see, thanks Susheel..

[Susheel Nuguru]

Glad that I could help.