multiperipheral with 64byte MTU

[Dream Cob]

Hello

I am working to connect several centrals(MAX : 4) for one peripheral. I found nRF5_SDK_14.1.0_1dda907\examples\ble_peripheral\experimental\ble_app_multiperipheral example for me in SDK library.

Based on this example and nus_uart example, I am going to implement multiperipheral firmware with NUS service, but it doesn't work for 64bytes MTU size. It works well on default MTU size 23bytes.

I want to increase to 64 bytes for MTU size.

SDK is 14.1 and S132. Please help me.

Thank you.

[endnode]

You cannot just say "it doesn't work for 64 byte MTU size", you need to debug it and say what goes wrong according to UART or RTT debug print-outs.

[Dream Cob]

Thank you for your comment. Yes, I have tried debug on RTT debugger, but I can't find the solution. when I add following function in gatt_init() function, it doesn't work.

err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, BLE_PACKET_SIZE + OPCODE_LENGTH + HANDLE_LENGTH); APP_ERROR_CHECK(err_code);

BLE_PACKET_SIZE is 65.

[endnode]

Again you cannot say "it doesn't work". You need to say "I did this and this, I'm expecting this and this but I see this instead". No one can help you with "it doesn't work" cry.

[endnode]

Just based on this info it suggests that stack don't have enough RAM space to allocate all the resources needed to handle larger MTU sizes in (G)ATT layer. But that would be indicated by certain error codes returned to some SD calls. So if you run the project with proper level of debug print-outs in UART or RTT console you should see it easily. That's why I'm asking what does it mean for you "it doesn't work". If you don't know what is happening inside your system then we cannot help you...