How to use uart in mesh, or printf?

[unvblestudy]

When I use 52832 to develop a mesh project and want to use uart to print information, I find that the code always reports an error because of the existence of printf. The sdk used in my development environment is NRF1710sdk and nrf mesh SDK5.0.0, developed in ses,what should I do to make it work normally?

[Edvin]

Hello,

Is it an alternative to use the __LOG() function to log data? Or do you need it to be on a very specific format?

Without knowing more about your project, and what's failing, it is hard to say what you need to do.

What do you mean by "normally"? What example did you start with, since it apparently has set up the printf() function over UART?

Best regards,

Edvin

[unvblestudy]

Thank you, Edvin! My statement is  not clear enough. I want to use uart to display information on a screen. I know that I can use log to view debugging information, but it seems that it cannot be used for regular screen information display. I am using the dimming code and added saadc to it. I want to display the data collected by saadc, but after I add the uart code in ses, the error of ‘printf’ will always be reported, so that the compilation cannot be completed. I don't know the reason.How can I resolve such an error？

[Edvin]

unvblestudy said:

Sorry, I accidentally pressed the button to confirm the answer, do I need to ask again?

It goes back to status OPEN when you reply, so it is fine.

Ok, I see. So 

#if NRF_MODULE_ENABLED(APP_UART)

uses the macro NRF_MODULE_ENABLED, which translates to :

((defined(module ## _ENABLED) && (module ## _ENABLED)) ? 1 : 0)

Which means that it really says.

#if ((defined(module ## _ENABLED) && (module ## _ENABLED)) ? 1 : 0)

where "module" is what's inside the parenthesis, and ## is a way to "stitch" strings together. 

So basically it checks whether APP_UART_ENABLED is defined, and whether APP_UART_ENABLED is defined to 1. If not both of those are true, then it will exclude the rest of the file (until the corresponding #endif comes).

Add this to your sdk_confi.h file somewhere:

// <e> APP_UART_ENABLED - app_uart - UART driver
//==========================================================
#ifndef APP_UART_ENABLED
#define APP_UART_ENABLED 1
#endif
// <o> APP_UART_DRIVER_INSTANCE  - UART instance used
 
// <0=> 0 

#ifndef APP_UART_DRIVER_INSTANCE
#define APP_UART_DRIVER_INSTANCE 0
#endif

// </e>

(I copied it from the ble_app_uart example's sdk_config.h file, which is an example that I know uses the app_uart).

If you find a line in your sdk_config.h saying: 

// <h> nRF_Libraries 

You can paste it somewhere below there.

Best regards,

Edvin

[unvblestudy]

Thanks for your guidance, Edvin! I have now solved the related error and got it running successfully, but when I use app_uart_put('p');, I don't see the output on the serial port software, how can I check if it is working properly? 

Best regards,

unvblestudy

[unvblestudy]

Hi, Edvin, I have browsed many other posts about uart and found that some people mentioned that rtt and uart cannot be used together, I am wondering if this is the problem I have encountered,because I use rtt in my code  for debugging observations.

Best regards,

unvblestudy

[Edvin]

Hello,

You can use RTT and UART together. What you cannot do is to use the UART both for logging and for your application. But if you use the RTT backend on the logging, you should be able to use UART in your application (app_uart_put()). 

What does app_uart_put() return?

ret_code_t err_code;

err_code = app_uart_put('p');

NRF_LOG_INFO("app_uart_put returned %d", err_code);

Best regards,

Edvin

[unvblestudy]

Hi,Edvin,sorry to bother you again, but I added this code and it returns 0,  I don't observe any value using putty, I don't know what to do with it now.

Best regards,

unvblestudy