Device getting Hard Reset when it gets disconnected due to going out of range

[KrishNa]

Hello,

We are working on a product that contains nRF51822. The product sends continuous data (2 bytes) via NUS service to the mobile app at a frequency of 200ms.

When the device is in range, it works fine but when it goes out of range and gets disconnected because of it, then the device gets reset.

The device does not get reset when the disconnection happened because of turning off Bluetooth. it gets reset only when disconnection happens because of going out of range.

Can you please help me to fix this issue?

Thanks in advance.

Best,

Krish

[Vidar Berg]

Hello Krish,

My guess is that the send function is returning an error code which is then passed to the APP_ERROR_CHECK() macro and causing the error handler to reset the device (see Error module).  Are you able to find out what the error code is?

Best regards,

Vidar

[KrishNa]

Hi Vidar,

Thanks for the quick reply. unfortunately, i am not able to find the error code. I tried debugging by commenting the function, that send the data continuously and everything works fine. but when the function is enabled, it always resets on going out of range...

Any insights from this will be of great help.

Best,

Krish

[Vidar Berg]

Hi Krish,

Are you able to get UART/RTT logs from this device, or can you attach a debugger to read the error code? Note that you can read the error code that lead to the reset from the from the app fault handler if you add 'DEBUG' to your preprocesor list (see Error module).

Best regards,

Vidar

[KrishNa]

Hello Vidar,

Thanks for your reply. I tried debugging and found out that the reset was happening because of the following error NRF_ERROR_INVALID_STATE returned by the function ble_nus_string_send.

Do you have any idea why this issue is happening when going out of range?

Best Regards,

Krish

[Vidar Berg]

Hello Krish,

Yes, NRF_ERROR_INVALID_STATE indicates that ble_nus_string_send() was called after the connection was lost. 

You can either ignore the error like this:

err_code = ble_nus_string_send(..);
if (err_code != NRF_ERROR_INVALID_STATE)
{
        APP_ERROR_CHECK(err_code);
}

Or you can verify the connection state before sending the data.

Documentation for the various return codes for ble_nust_string_send()::sd_ble_gatts_hvx() can be found here: https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s130.api.v2.0.1/group___b_l_e___g_a_t_t_s___f_u_n_c_t_i_o_n_s.html#ga313fe43c2e93267da668572e885945db

Best regards,

Vidar