examples\peripheral\uart - printf is not working

[Ron]

Hallo

Im using the example of nRF5_SDK_12.3.0_02\nRF5_SDK_12.3.0_d7731ad\examples\peripheral\uart

to setup a uart that includes rx as well as tx, 

I am running the example on the NRF51 DK 

My problem is as the title suggest is the TX, via the printf, I have also tried the  app_uart_put and to use the app_uart_flush();

up until now I have successfully used the LOG feature (initialization with NRF_LOG_INIT()) , and now I want to add rx

I have taken the uart example as it is ,(initialization based on APP_UART_FIFO_INIT()) aside for the following changes :

- changes to the pin num to match my desired rx and tx pins.

- changes to the RAM/ROM configurations which i will add here as a image, It worked with the same configuration when I used the log option

I know the rx pin is correct and the hw is ok since I receive rx properly with the example

I know the tx pin is correct and the hw is ok since I used the same tx pin for the log

however, with the fifo (uart example) the printf() is not working

I have no idea why

would very much appreciate some ideas on how to move forward

Thanks !

Eran

[Hung Bui]

Hi Eran, 

Could you explain which exactly the problem you have now ? It's not very clear from your description. 

When you run the uart example in the SDK (which in the image you provided ? ) do you have any problem ? 

If you are integrating APP_UART_FIFO into your project, please make sure you include app_uart_fifo.c and app_fifo.c in your project. 

Basically printf function will use fputc to print out each characters and fputc is redefined in retarget.c to use app_uart_put () to send the character out to UART port. 

[Ron]

Hi Hung

the problem is that there is not output on the uart_tx

I have used the uart example as is

thanks

Eran

[Hung Bui]

Hi Eran, 

If you have a nRF51 DK please try to test the uart example without any modification. A logic analyzer would be useful to check if there is any output on the TX pin. 

Both the NRF_LOG module and APP_UART uses nrf_drv_uart to output data to uart. I would suggest to try using the nrf_drv_uart to output some data. 

Usually the uart example works out of the box with the nRF51 DK. You can try to test with a fresh copy of the SDK, just to be sure.