Session Run Time BLE CGMS characteristic

RE: Session Run Time BLE CGMS characteristic

Kenneth — Tue, 28 Sep 2021 13:40:27 GMT

[quote user="pedrovfr_LNNano"]Ok, what I am understanding is that the structure of this characteristic is implemented by the Softdevices (such as the "hours" text displayed in the peer) following the SIG's specification, and I can't actually change any of that and just pass the mandatory value through the 16bit field.[/quote]

That is not technically correct, the softdfevice doesn't care about the data written, the data is just passed to the peer if read. However the whole point with having a Bluetooth profile is interoperability, if you change the data then you are no longer complying to the Bluetooth specifications. So if you need to have data that does not comply to a specific profile, then you will need to add this as a custom profile.

Kenneth

RE: Session Run Time BLE CGMS characteristic

pedrovfr_LNNano — Tue, 28 Sep 2021 11:58:13 GMT

Ok, what I am understanding is that the structure of this characteristic is implemented by the Softdevices (such as the "hours" text displayed in the peer) following the SIG's specification, and I can't actually change any of that and just pass the mandatory value through the 16bit field.

Is that right?

To present the value in minutes should I implement a custom service or can I modify the present CGM SRT service somehow?

RE: Session Run Time BLE CGMS characteristic

Kenneth — Tue, 28 Sep 2021 09:10:08 GMT

In GSS (current version is v5, available here https://www.bluetooth.com/specifications/specs/gatt-specification-supplement-5/ ) you can find the description. In short, it has 1 16bit mandatory field for the session run time and one optional field for the CRC.

unit: org.bluetooth.unit.time.hour

RE: Session Run Time BLE CGMS characteristic

pedrovfr_LNNano — Mon, 27 Sep 2021 12:07:04 GMT

Ok, but how can I change this or even update the minutes on this characteristic?

Also the Figure 1 on the document refers to the Session Start Time, my issue is more related to the Session Run Time.

RE: Session Run Time BLE CGMS characteristic

Kenneth — Mon, 27 Sep 2021 11:23:16 GMT

The softdevice doesn't really care what data that is passed here, and the application will try to follow the BLE specification on the format of the data that should be passed. From Figure 1 in the BLE service specifications it seems this should be in hours:minutes:
https://www.bluetooth.com/specifications/specs/continuous-glucose-monitoring-service-1-0-1/

Kenneth