5 Replies Latest reply on Jun 21, 2014 7:30 PM by MichaelF_56

    Call event for Read characteristic value

      Hello Team

         

      As you can see the below picture which is scrapped from SIG 4.8.1, the Bluetooth side want to get the Read event call back feature, would you please help me on that how to receive the Read event?

       

      Thank you

      Daniel

        • 1. Re: Call event for Read characteristic value
          ArvindS_76

          The stack handles all characteristic reads and there is currently no callback into the app when processing a read request.

          • 2. Re: Call event for Read characteristic value
            MichaelF_56

            gattDB.png

            • The application writes characteristic values to GATT DB
            • The peer reads from the GATT DB, but the application does not need to know how and when read is performed
            • The peer writes to the GATT DB and an application callback is issued. 
              • The application can then read the data from the GATT DB
            • If a write requires an acknowledgement, it is provided by the stack without application involvement
            • 3. Re: Call event for Read characteristic value

              My consideration is that the Android app is only available up to write and read a characteristic value for 20 bytes, and therefore the client application require to write many times for a large BLOB characteristic value, and also the application should use the issued Write Callback in order to read a value from the GATT DB.

               

              But on the other hand, when the client application require to read a large BLOB value from the GATT DB, What is good to write the large BLOB value by the application side, and also what is good to read the large BLOB value by the client application side? Should we need to define a new Write characteristic value in order to handshake between them although there are many resource required?  Is there any good way to read the large BLOB value rapidly?

               

              • 4. Re: Call event for Read characteristic value
                MichaelF_56


                I've escalated this internally to the software team to see if they can provide guidance on the best method to read and write large BLOB values, or if this is even possible.

                • 5. Re: Call event for Read characteristic value
                  MichaelF_56

                  I checked with the software team and the method described does not exist yet, but we will try to patch it in within the next SDK release if the product team agrees it's a necessary feature.

                   

                  Note that large BLOB will be fragmented into 20 byte packets anyway, so there is no real benefit other than a slight application convenience. 

                   

                  The application can easily create 512 bytes buffer and then read/write data into the buffer.