Hardfault after BLE connection, in BLE with ADC app

[Alaa]

Hi,

I'm using SDK 14. I started from ble_uart application, and to use ADC as well I ported ble_app_uart__saadc_timer_driven__scan_mode (SDK 13) to SDK 14 (made changes in main.c, sdk_config.h, Makefile). It compiles and runs fine.

Here's an example from the run:

Now I search for the device by a smartphone through BLE and I find it and connect successfully.

The problem is that once I connect to it, the device falls into a hard fault:

Any help is appreciated...

Thank you!

[Turbo J]

Why dont't you just look at the call stack (gdb: "bt" command)?

[Alaa]

Good point!
It was coming from 

APP_ERROR_CHECK(err_code);

err_code was equal NRF_ERROR_INVALID_PARAM

I'm not sure how this is causing hard fault but disabling this error check solved the problem.

Thanks

[Turbo J]

You should rather fix the call that generated the error code...

[Alaa]

This was happening in the function saadc_callback() after executing the following:

err_code = ble_nus_string_send(&m_nus, value, bytes_to_send);

Which tries to send data via BLE. Currently I'm sending data in another function outside of saadc_callback() and it's working.

But you're right; the root cause of the problem should be fixed. I'm not sure where this is coming from though so I think I'll wait for responses...

[Turbo J]

The ble_nus_string_send() function can give you a "TX buffer full" return code for example, which you should handle somehow. Usually that means redesigning some stuff using FIFOs.

[Alaa]

As I said, it gave NRF_ERROR_INVALID_PARAM, and not TX buffer full