Android: Sending data >20 bytes by BLE

RE: Android: Sending data >20 bytes by BLE

user67282 — Thu, 04 Jan 2018 07:12:02 GMT

Hey can I get this working for iOS..??, I'm able to send data to BLE but on Serial printer it shows the partial data only.

RE: Android: Sending data >20 bytes by BLE

user7418 — Tue, 17 May 2016 21:02:44 GMT

The requestMtu method has been added in the Android API 21. @hungbui could you please confirm if any SoftDevice support larger MTU (the ATT_OP_MTU_REQ opcode 0x02 according to the spec) ?

According to this commit of the Android-nRF-Toolbox project, long writes are supported by the Android BLE stack if the write type is set to WRITE_TYPE_DEFAULT (ATT write request).

RE: Android: Sending data >20 bytes by BLE

user4172 — Wed, 18 Jun 2014 10:15:39 GMT

I got this working finally. onCharacterisiticWrite() was important but if we only write and don't read from the firmware, then writing is a very fast process and after implementing this too I only get the last part. The trick for this is Thread.sleep(150). Delay the process by 150 milliseconds and it works! Thanks for the guidance.

RE: Android: Sending data >20 bytes by BLE

Hung Bui — Wed, 18 Jun 2014 09:11:03 GMT

Hi Ankit, Seems that on Android long write is not supported, you would need to split your large data in to chunks of 20 bytes packet.

You would need to make sure the packet is queued correctly before you send the next packet. First you have to check for the return code of BluetoothGatt.writeCharacteristic(). Second you would need to wait for the call back BluetoothGattCallback: onCharacteristicWrite() before you queue the next packet.