Communication between two nRF52840 boards through BLE

[BMG]

Hello,

I have 2 pieces of nRF52840 and I managed to connect each other. One is central, uploaded the code: 'nRF5_SDK_15.3.0_59ac345\examples\ble_central\ble_app_multilink_central' and the second is peripheral, with the code: 'nRF5_SDK_15.3.0_59ac345\examples\ble_peripheral\ble_app_blinky\'.

The problem is that I don't know how to communicate each other/ send a string from central to peripheral and when the peripheral receives that string, to do something.

Do you have an example code or how can I do this?

Thank you.

[Mttrinh]

Hi,

You should able to do this with the UART example from our SDK. Have look at these two examples: 

Nordic UART Service Client(Central), can be found in <InstallFolder>\examples\ble_central\ble_app_uart_c

UART/Serial Port Emulation over BLE(Peripheral), can be found in <InstallFolder>\examples\ble_peripheral\ble_app_uart

[BMG]

Are there functions to send a string from central to peripheral?

[Mttrinh]

You can use this function to send a string: ble_nus_c_string_send().

[BMG]

Thank you for the answer! But I have a problem with the  <InstallFolder>\examples\ble_central\ble_app_uart_c project, in function:

ret_code = sd_softdevice_enable(&clock_lf_cfg, app_error_fault_handler); 

called from  nrf_sdh_enable_request() in ble_stack_init() function:

I think it's a reset and I don't know how to solve it because the file containing the implementation of  sd_softdevice_enable() function is not compiled in the project. I think it's a separate library where its implementation can be found and I don't have access to this. That's why I can''t do debug.

How can I solve this?

[Mttrinh]

Hi,

That is a softdevice function which isn't open source, so like you said you won't have access to it.

Have you modified anything in the example? I suspect it might be just a problem with memory. Try setting the define "DEBUG" in your preprocessor and set a breakpoint at the function app_error_fault_handler(). Then try to debug the code, this will let you see which error code that is returned from the function.

[BMG]

Hi Mttrinh,

I checked the function app_error_fault_handler() and the program doesn't get there, so I am not able to see which error code returns the function.

I suppose that the problem is the softdevice and I have several questions:

1. How can I verify which version of softdevice it's on the board?

2. Do I have a softdevice on my board by default? I have sparkfun nrf52840 mini.

3. How to do an update to softdevice 7.0.1?

4. The examples from nRF5_SDK_15.3.0_59ac345 with which versions of softdevice are running? 

5. The example "nRF5_SDK_15.3.0_59ac345\examples\ble_peripheral\ble_app_blinky" doesn't have any problem with ble_stack_init() function and it works well. I don't know why only some examples work and others are stuck at ble_stack_init().

Thank you.