Hello
NRF52840 with own hardware
nRF SDK V17.0.2_d674dde
nRF SDK for Mesh V5.0.0
IDE: SEGGER 5.60
I started with the "ble_peripheral/ble_app_template" example and added the mesh functionality.
I use the following setting:
NRF_SDH_BLE_GAP_DATA_LENGTH 27
NRF_SDH_BLE_GATT_MAX_MTU_SIZE (NRF_SDH_BLE_GAP_DATA_LENGTH - 4)
With this setting the provisioning with the nRF Mesh app works well.
During compiling i get the warning: " An MTU size of 69 octets is recommended."
When i set the NRF_SDH_BLE_GAP_DATA_LENGTH 73 and the NRF_SDH_BLE_GATT_MAX_MTU_SIZE 69 to fullfill the recommend advice
the provisioning failed
Error Message in APP is Provisioning failed - prohibited after "Provsioning public key received"
NRF_SDH_BLE_GAP_DATA_LENGTH 27
<info> app: Fast advertising.
<info> app: ble connected
<debug> nrf_ble_gatt: Peer on connection 0x0 requested an ATT MTU of 517 bytes.
<debug> nrf_ble_gatt: Updating ATT MTU to 23 bytes (desired: 23) on connection 0x0.
<info> app: device start identification
<info> app: device stop identification
<info> app: Fast advertising.
<info> app: ble disconnected
<info> app: successfully provisioned
<info> app: node address: 0x0132
<info> app: ble connected
<debug> nrf_ble_gatt: Peer on connection 0x0 requested an ATT MTU of 517 bytes.
<debug> nrf_ble_gatt: Updating ATT MTU to 23 bytes (desired: 23) on connection 0x0.
NRF_SDH_BLE_GAP_DATA_LENGTH 73
<info> app: Fast advertising.
<debug> nrf_ble_gatt: Requesting to update ATT MTU to 69 bytes on connection 0x0.
<debug> nrf_ble_gatt: Updating data length to 73 on connection 0x0.
<info> app: ble connected
<debug> nrf_ble_gatt: ATT MTU updated to 69 bytes on connection 0x0 (response).
<debug> nrf_ble_gatt: Data length updated to 73 on connection 0x0.
<debug> nrf_ble_gatt: max_rx_octets: 27
<debug> nrf_ble_gatt: max_tx_octets: 73
<debug> nrf_ble_gatt: max_rx_time: 328
<debug> nrf_ble_gatt: max_tx_time: 2120
<debug> nrf_ble_gatt: Peer on connection 0x0 requested an ATT MTU of 517 bytes.
<debug> nrf_ble_gatt: Updating ATT MTU to 69 bytes (desired: 69) on connection 0x0.
<debug> nrf_ble_gatt: Peer on connection 0x0 requested a data length of 73 bytes.
<debug> nrf_ble_gatt: Updating data length to 73 on connection 0x0.
<debug> nrf_ble_gatt: Data length updated to 73 on connection 0x0.
<debug> nrf_ble_gatt: max_rx_octets: 73
<debug> nrf_ble_gatt: max_tx_octets: 73
<debug> nrf_ble_gatt: max_rx_time: 2120
<debug> nrf_ble_gatt: max_tx_time: 2120
<info> app: device start identification
<info> app: device stop identification
<info> app: Fast advertising.
<info> app: abort provisioned
<info> app: ble disconnected
What do I have to adjust so that the provisioning with MTU Size 69 is working?
Why i should not use a higer MTU size. For example: 247
I found some topics in the DevZone but they didn't solve my problem.
regards
Michael