QUERY · ISSUE

Pyboard-D BLE unsolicited disconnects on handle 65535

openby diginfoopened 2019-11-08updated 2019-11-11

port-stm32

I have reported this on the forum, but think maybe it is a bug and so reporting it here.

I am getting 'unsolicited' disconnect interrupts with handle 65535, this will happen for sure if a device is connected and you do a soft reboot, it appears that during the restart the device is disconnected but as it does not have a valid handle for the new session, that it will trigger this event.

But I also get it intermittently without a restart, and immediately following this 65535 disconnect, the next connection will fail.

CANDIDATE · ISSUE

extmod/bluetooth: handling of disconnect in ble_simple_central.py example is misleading

openby tveopened 2021-01-25updated 2021-01-25

The handling of the disconnect event in ble_simple_central.py is misleading. The condition if conn_handle == self._conn_handle:
(line 108) makes it look as if a different value for conn_handle would mean that there's nothing to do, but this is not the case. In particular, a disconnect can happen during the connection process, at least with nimble on the esp32, in which case self._conn_handle is still None and conn_handle != self._conn_handle but calling self._reset() is necessary.

https://github.com/micropython/micropython/blob/203e1d2a65273db3f6ff063ba1124a89c3482c0f/examples/bluetooth/ble_simple_central.py#L108

Assessment

Q Qwen · medium

Both issues concern BLE disconnect event handling in MicroPython, but they address different specific problems. Issue #5307 reports a bug on the STM32 port where unsolicited disconnect events with invalid handle 65535 (0xFFFF) occur during soft reboot and intermittently, causing connection failures. Issue #6796 reports a logic flaw in the example code (ble_simple_central.py) where the disconnect handler condition is misleading - it suggests no action is needed when conn_handle differs from self._conn_handle, but cleanup is still required during connection attempts. While both involve BLE disconnect handling, #5307 is about a core port bug with invalid handle values, whereas #6796 is about example code logic and connection state management. They share the same component area but have different root causes and symptoms.

Suggested action

Keep both issues open as they address different problems. The maintainer may want to review if the core disconnect handling logic in #5307's root cause could inform improvements to the example code in #6796, but they are not duplicates.

Pyboard-D BLE unsolicited disconnects on handle 65535

extmod/bluetooth: handling of disconnect in ble_simple_central.py example is misleading

Keyboard