NRF52840-Dongle PCA10059, UART problem.

[cann0021]

Hello everybody.

I have been working on nRF52840 for a time. I am trying to flash the chip with ble_app_uart_c (SDK 15.3.0). I have applied everything essential, but my dongle restarts consecutively. I want to use 0.24 as TX pin. I have edited pca10059.h header file for this but, unfortunately I am having trouble with UART. I just want to send some data to another device(via GPIO) using UART. Please help me. Thank you very much. 

[Kenneth]

Hi, try to add a pull-up on the RX pin. That said, seems you have an assert, so check out these tutorial on how to add DEBUG to find the file name and line number for the assert:

https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/an-introduction-to-error-handling-in-nrf5-projects 

[cann0021]

Hi, thank you for the response. The error I am getting occurs in uart_event_handle() function and in APP_UART_COMMUNICATION_ERROR case. When I print the error code I observe 12(decimal). What does "12" mean ?

[Kenneth]

I assume it is combination of BREAK and FRAMING error:

https://infocenter.nordicsemi.com/topic/ps_nrf52833/uarte.html?cp=3_1_0_5_31_8_20#register.ERRORSRC 

This is common to get if RXD is floating (not connected logic high).

[cann0021]

I am using only TX. RX is defined as NULL in my board's header (.h) file. No need to use RX in my case. Will it still cause a problem ?

[Kenneth]

Can you read out the actual content of PSEL.RX register:
https://infocenter.nordicsemi.com/topic/ps_nrf52840/uarte.html?cp=3_0_0_5_33_8_25#register.PSEL.RXD 

I think you should use UART_PIN_DISCONNECTED instead of NULL.