Hallo,
we are using an nrf5340 SOC together with the SDK v1.9.0.
When running the sample "ncs_ble_tutorial_part1" from here
we observed that maximum 20 bytes can be written to the "MY_SERVICE_RX" characteristic.
My Question:
Which modifications have to done to increase the number of byte to be transferred from 20 to e.g. 500 ?
Best regards
Georg
Best regards Georg
Hallo,
With the default kconfig settings the Bluetooth zephyr host and Softdevice controller will give you an ATT_MTU size of 23 bytes which limits your effective payload to 20 bytes after you account for the GATT header.
With the following configuration you should be able to write up to 244 byte of payload in one write command:
<project_dir>/child_image/hci_rpmsg.conf
<project_dir>/prj.conf
Project from tutorial with the updated configuration settings above:
Best regards,
Vidar
Edit: here's another thread with a similar question : https://devzone.nordicsemi.com/f/nordic-q-a/87829/updating-mtu-size-for-tx-and-rx-with-android-ble-client
Hallo,
With the default kconfig settings the Bluetooth zephyr host and Softdevice controller will give you an ATT_MTU size of 23 bytes which limits your effective payload to 20 bytes after you account for the GATT header.
With the following configuration you should be able to write up to 244 byte of payload in one write command:
<project_dir>/child_image/hci_rpmsg.conf
<project_dir>/prj.conf
Project from tutorial with the updated configuration settings above:
Best regards,
Vidar
Edit: here's another thread with a similar question : https://devzone.nordicsemi.com/f/nordic-q-a/87829/updating-mtu-size-for-tx-and-rx-with-android-ble-client
