Handling different offset in BaseUUID and pc_ble_driver

RE: Handling different offset in BaseUUID and pc_ble_driver

gtorres — Tue, 17 Jul 2018 23:05:56 GMT

I am going to expose the attr_handle through the python interface. I think that's what is missing.

Thanks Terje.

RE: Handling different offset in BaseUUID and pc_ble_driver

gtorres — Tue, 17 Jul 2018 22:15:13 GMT

Terje,

That worked, but it does not allow me to tell which characteristic is actually triggering a notification. I can subscribe to two different base UUIDs with the same offset (because bytes 12 and 13 are constant). The "on_notification" function gets called with a uuid parameter that is the same for both characteristics, even though they have different bases. When inspecting the uuid object passed, it looks like the base uuid is not populated (set to None).

Without a meaningful way to tell which characteristic is triggering a notification, its nearly impossible to piece together a message. Do you know if there is a way to tell them apart?

In my example, the UUID field is simply set with `e4bc` for both characteristics.

Thanks,

Gabe

RE: Handling different offset in BaseUUID and pc_ble_driver

tesc — Tue, 17 Jul 2018 17:30:23 GMT

Hi,

Then I think there should be a call somewhere to BLEEnableParams() where you set vs_uuid_count. See for instance the pc-ble-driver-py heart rate collector example, heart_rate_collector.py, lines 69 to 73. That should be the way to configure the SoftDevice in pc-ble-driver-py.

Regards,
Terje

RE: Handling different offset in BaseUUID and pc_ble_driver

gtorres — Mon, 16 Jul 2018 22:20:31 GMT

Terje,

Yes, I'm using pc-ble-driver-py

RE: Handling different offset in BaseUUID and pc_ble_driver

tesc — Mon, 16 Jul 2018 19:59:07 GMT

Hi,

If you use the SoftDevice Handler from our SDK (which most SDK examples do) then it is NRF_SDH_BLE_VS_UUID_COUNT in sdk_config.h.

Edit: Whoops, sorry, didn't realize the python comment. Are you using pc-ble-driver-py?

Regards,
Terje

RE: Handling different offset in BaseUUID and pc_ble_driver

gtorres — Mon, 16 Jul 2018 17:46:52 GMT

Terje,

Thanks for the reply. Can you point me in the right direction as to where I can change the base uuid limit? I'm not sure if that is part of the softdevice that is flashed to the dongle or part of the shared library that the python bindings use.

-Gabe

RE: Handling different offset in BaseUUID and pc_ble_driver

tesc — Mon, 16 Jul 2018 12:54:36 GMT

Hi,

The system with base UUIDs that are combined with a 16 bit value to form a full 128 bit UUID are made specifically to use bytes 12 and 13 as the shorter 16 bit portion of the full 128 bit UUID. This is handled internally in the SoftDevice and cannot be changed.

That means you must do as you describe and manually create a set of base UUIDs and 16 bit UUIDs in order to compose the actual 128 bit UUIDs that you need. And, as you wrote, accept the memory usage resulting from such an approach.

Regards,
Terje