nrf5340 nus_cb does not work in peripheral_uart example

[Atilla Golan]

I have sdk 2.1.0 and nrf5340, trying to run peripheral_uart sample connecting nrf5340 to a module via uart. The program seems working when only works with nrf5340 based on the test instruction here https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/bluetooth/peripheral_uart/README.html but while is connected to the bluetooth module via uart, bt_receive_cb prints the buffer in RRT console but nuc_cb (ble_write_thread) does not print anything to RTT console. It does not work with nrf connect app on my mobile phone: sending from mobile is okay but cant receive anything from uart_cb. 

[Hung Bui]

Hi Atilla, 

Have you verified the UART communication between the nRF5340 and the module is working fine (both ways)?  
Do you have a nRF5340 DK to test ? 
If you do I would suggest to test on nRF5340 DK to communicate with PC first and after that test with the UART connection with the module. 

[Atilla Golan]

I have done this both ways work.

[Hung Bui]

Hi Atilla, 
From what you described I can only point to the issue in UART communication between your board and the module. 
In ble_write_thread() the thread would read from UART buffer and then send it over to BLE. You may want to debug there and see why there was no data in UART buffer. What data do you send from the module to the nRF5340 ? 
You may also want to put some log in uart_cb() and check if the function is called at all. You can start by try sending some dummy data on UART (directly to UART without BLE) to see if you receive UART_TX_DONE call back or not. 

[Atilla Golan]

Thanks

nus_cb does not called at all, I have doubt about uart_tx and if it should triggered by int_handler somewhere. I wonder if there is any nus sample for nrf5340. 

[Hung Bui]

Hi again, 

The peripheral_uart would work out of the box with nRF5340DK. 
I just did a test here and had no problem seeing the data from phone output to UART: 

I would suggest to get hold of a NRF5340DK to test with.