Adding Multiple Presentation Format Descriptors

RE: Adding Multiple Presentation Format Descriptors

eric-appion — Wed, 28 Nov 2018 19:12:55 GMT

I have the same issue, with multiple quantities in a single characteristic, which shouldn't be split up because they are closely related and normally need to be written together. In one case I have two float32 values followed by a uint8. I'd like to have the CPF descriptors and CAF descriptor so that peers that aren't hard-coded can parse it properly.

It would be especially nice if nRFConnect would recognize that and deal with it appropriately, but I'm not really expecting that.

RE: Adding Multiple Presentation Format Descriptors

Joshua — Fri, 31 Mar 2017 20:52:02 GMT

It can be hard-coded in the peer side, it is not really needed, I just figured it would be useful.

RE: Adding Multiple Presentation Format Descriptors

Hung Bui — Tue, 28 Mar 2017 09:57:13 GMT

Hi Joshua,

Unfortunately, the feature is not supported in our current softdevices. We allow adding Characteristic Aggregate Format but not multiple Characteristic Presentation Format.

Is it possible that you split your characteristic into 4 ?

Would the format really needed to be there in the GATT or it can be hard coded in the peer side ?

RE: Adding Multiple Presentation Format Descriptors

Joshua — Fri, 24 Mar 2017 22:45:48 GMT

Yes, it fails with the error code NRF_ERROR_FORBIDDEN for the UUID corresponding to a presentation format descriptor.

RE: Adding Multiple Presentation Format Descriptors

Petter Myhre — Fri, 24 Mar 2017 10:18:23 GMT

Have you tried to use sd_ble_gatts_descriptor_add()?

RE: Adding Multiple Presentation Format Descriptors

Petter Myhre — Thu, 23 Mar 2017 14:04:17 GMT

Could you explain a bit more? Why do you need multiple descriptors?