Issue with 2 centrals and single peripheral

RE: Issue with 2 centrals and single peripheral

Mttrinh — Tue, 09 Jul 2019 09:27:57 GMT

It is weird that it isn't timing out after some time. Which event do you get when you get a match? Is this event triggered NRF_BLE_SCAN_EVT_CONNECTED?

Could you try changing this value NRF_BLE_SCAN_SCAN_DURATION?

RE: Issue with 2 centrals and single peripheral

prodey — Tue, 02 Jul 2019 13:16:48 GMT

Just to clarify above reply : "In this condition, if I restart the peripheral, the central gets out of this condition and periodically starts getting the BLE_NUS_C_EVT_NUS_TX_EVT event". In this condition, the other central gets into a normal scanning mode.

RE: Issue with 2 centrals and single peripheral

prodey — Tue, 02 Jul 2019 13:13:44 GMT

I do not get any error codes on the central device. I tried to probe all the timeout events and BLE_GAP_EVT_DISCONNECTED event through LED indicators on our hardware, but none of these are hit once the device gets a match. In this condition, if I restart the peripheral, the central gets out of this condition and periodically starts getting the BLE_NUS_C_EVT_NUS_TX_EVT event. It seems, when there is a device name match, the central waits forever till it receives BLE packets from the exact same peripheral device that caused the match without ever getting into a timeout.

My constant NRF_BLE_SCAN_SUPERVISION_TIMEOUT is set to 1000 which I guess is 10 sec timeout. I tried to change this value but it does not affect this behavior. Our periodic messages from peripheral are being sent at 10 ms.

I can handle this on the application side. I start a timer set for 1 sec on device name match and check for a global variable that increments in ble_nus_c_evt_handler(). If it has not incremented for 1 sec, I reset the device trough sd_nvic_SystemReset(). With that, the central starts normal scan again and is ready to pair with any other peripheral.

However, I believe there is a better way to handle this than such frequent resets to the device.

Please suggest.

RE: Issue with 2 centrals and single peripheral

Mttrinh — Tue, 02 Jul 2019 08:13:45 GMT

Hi,

Sorry for the late response.

Do you get any error codes when the device is stuck?

If both get centrals are getting a match, the one central that doesn't establish a connection with the peripheral should get a timeout. After the supervision timeout has passed, you should get a BLE_GAP_EVT_DISCONNECTED event. What is your supervision timeout set to?