Forced disconnections when i try to send 50 bytes per second on UART example

[sotillo2409]

Hi everyone,

Explaning my project: an external device transmit via UART to nordik nrf52840DK device with UART peripheal firmware, this is connected to another nrf52840DK via BLE with UART central firmware.

So the peripheal is only working as bridge.

It simply works when i send less than 10 bytes per second, but when I increase the amount of data to more than 30bytes per second i get disconnexions of my peripheal when passed 20-40 seconds. 

I tink that it could be an overload of the UART or an overload of BLE, here my conn_params:

Here the error of disconnection: Disconnected: <log_strdup alloc failed> (reason 8)

Really the objective of the project is send 50-100 bytes every 100msec.

What point i need to check or reconfigure to achieve it??

Thank you,

regards.

[Einar Thorsrud]

Hi,

Disconnect reason -8 is timeout, so it would be interesting to know what happened on the other device, as it seemingly stopped maintaining the connection. Can you try to debug on the nRF that did not get the -8 disconnect, and see what happened there? Perhaps you did not properly handle full buffers, and that lead to a APP_ERROR_CHECK being hit, or similar?

[sotillo2409]

Hi, looking it better the Disconnect reason -8 is coming of the central Device, so i will try to debug peripheal to see which is the reasson of it disconnection

[sotillo2409]

As u recommend:

And in line 676 of main.c

I increase the STACKSIZE=1024 to 20*1024 and the error keeps continuing

[Einar Thorsrud]

I see. Now we know that there exception happens in ble_write_thread, but not what causes it. Can you share the implementation of that function?

[sotillo2409]

Is the default function to do the bridge on UART example

[Einar Thorsrud]

I see. Can you upload the full project (Bluetooth peripheral_uart sample with some modifications I assume) so that I can test the exact same thing as you on my side?

[sotillo2409]

peripheral_uartF_ML1.zip

Thanks for the interest on debug my project, is so important to mi achieve this.

To reproduce my configuration you should compile that project with another board (I use a custom board named hello_board, the only difference with nrf52840 dk are the UART, buttons and Leds pins).

Firstly u should close a communication between 2 devices, my project use a filter by name, and only work on coded phy, so i will upload Central UART too to make you easier.

Later you should send packets of 50 bytes every second from another device to UART rx pin of peripheral.

If this happend while there are a communication the error must happen.

Thank you, regards.

central_uart_ML1.zip

[Einar Thorsrud]

Hi,

I am sorry for the delay. I have not been able to test this yet but will give it a shot soon, hopefully tomorrow. Have you made any progress since last week?

[sotillo2409]

Hi, 

don't worry about the delay, i have been testing the examples more, and improving my structure of manage connection/disconnection between devices.

What I was trying is send this time from the central to the peripheral. I get an error relationed with the buffers that i post on another thread. https://devzone.nordicsemi.com/f/nordic-q-a/79820/help-to-understanding-error-not-able-to-allocate-uart-receive-buffer

But the ble communication seems to work properly, so i guess that the issue of this thread is going to be something realtioned with buffers, configuration, k_free function on peripheral project,

I will update with news,

regards

[sotillo2409]

I think i am having troubbles with flow control of uart

[sotillo2409]

Hi another time,

If you didn't be able to debug my project until now, there aren't any problem, but i work a little more on the projects, and as i can see only is keeping the error of BUS Alert, but with some differences on directions, i will update all information:

For reproduce this error is necessary have a connection of 1 central and 1 peripheral. On one of any devices connect to a external UART(for example xctu) and send periodically a packet of 5 bytes + \r +\n every second.

The error happens on the device where the external UART is connected and sending data. Aparently the device reboots randomly. This is an example of the issue on Central:

Debuging on direction 0x0029e5c:

On thread.c line 828:

To see wich thread is causing this:

On hci_core on line 65:

This thread isn't the same of the last time, I CONFIG_BT_RX_STACK_SIZE=2200 and CONFIG_BT_HCI_TX_STACK_SIZE=2200

and the error continue...

I don't know what more try.

Thank you,

regards.

[Einar Thorsrud]

Hi,

I thought the fault happened on the peripheral device? Now I see you have a bus fault on the central device as well?

Can you try to make a minimal failing project that reproduce the issue using a single DK, and using any device (like nRF connect for Desktop BLE) as the peer? Also it should not rely on physical UART, but just send some dummy NSU data in firmware. That way it is easier to test and also fewer variables to look into. Also, if stripping away parts of your firmware changes the behavior that gives an indication on where to look.