Hello!
We are using an BLE NRF51822 chip as a GATT-Server, unfortunately without any possibility to modify its software at the moment. The BLE-setup should be very similar to this one [http://developer.nordicsemi.com/nRF51_SDK/nRF51_SDK_v7.x.x/doc/7.2.0/s110/html/a00061.html]. An Android application works as a client, allowing us to write GATT-characteristic values. During the reliable characteristic write process there are two responses from the GATT-server to the client: “Prepare Write Response” and “Execute Write Response” (Bluetooth
Core Specification 4.2) [https://www.bluetooth.org/en-us/specification/adopted-specifications]. We see, that the first one (“prepare write”) saying the server is ready to proceed and as per definition already has the new value to be written(!) takes only 2 ms in average. But the second one (“execute write”) takes about 90 ms to finish. And yes, of course only for writing that single value (8 byte) sent in step one. Any ideas on how such a delay could be explained?
As the reliable write is at the moment the only method to messure the transmission + characteristic write time, we would like to know, how long it would take in general to write an 8 byte characteristic value without any server confirmation. Any experiences concerning this matter so far? Any chances we could write those values faster, if server-software modifications could be done; if yes, which options should we consider?
Thank you very much!
Alex
