BLE Nano v2 nRF52832 notify issue

[fgaetani]

Hi guys, I’m doing several tests with my new RedBear BLE Nano v2 board based on nRF52832 using the RedBear library, but I found a problem with reading Notify Characteristics. In my case I have a streaming of values with 100Hz sample rate (every 10ms) from a BLE Device, in particular from Android Smartphone. But, using the BLE_CentralTest Example, I can not obtain the value with 100Hz frequency. I receive 3 values in 1.5ms (very fast) and the fourth value after 123ms (very very slow). In my opinion the problem is in a buffering technique, but i do not known how to solve it because I read the values every time the hvxCallBack function is recalled. I have already tried to read the values with another BLE device and the frequency is correct.

Have you had similar issue, do you know how to solve it?

Thank you very much guys!

[Turbo J]

But, using the BLE_CentralTest Example, I can not obtain the value with 100Hz frequency.

Hitting the 100 Hz exactly is impossible on Android, because the minimum interval it uses is 15ms.

You need to request this interval from code using:

bluetoothGatt.requestConnectionPriority(BluetoothGatt.CONNECTION_PRIORITY_HIGH);

Note that the NRF52 has buffers for notifications and other TX data, so you could send more than one data value during one connection interval time slice.

[fgaetani]

Ok, I understand that 100Hz is high for an Android device, but the hole of 123ms is very strange! What could be the cause?