Confused with the pins assigned to NRF_LOG_INFO() and printf()

[beemavishnu]

Hello,

 

I am using nRF52832 DK PCA10040 v1.2.4, SDK_15.3.0, S132 SoftDevice and Segger for flashing the image. I am using ‘ble_app_blinky’.

 

I have very basic query.

 

1) In block diagram I am seeing only one UART. This can be enabled with or without EasyDMA. Without EasyDMA it is just UART whereas with EasyDMA it is UARTE. Is my understanding is correct ?

 

2) In ‘uart’ example, printf() is working. This uses UART (Without EasyDMA). To cross check, (On Development kit) I changed pin configuration in pca10040.h as below and it did not work. So to my understanding printf() uses UART with instance 0 and pins as 5, 6, 7 and 8.

 

 

    #if 1 // As is in Development kit
        #define RX_PIN_NUMBER           8
        #define TX_PIN_NUMBER           6
        #define CTS_PIN_NUMBER          7
        #define RTS_PIN_NUMBER          5
    #else
        #define RX_PIN_NUMBER           11
        #define TX_PIN_NUMBER           12
        #define CTS_PIN_NUMBER          13
        #define RTS_PIN_NUMBER          14
    #endif

 

3) If “uart’ example uses UART to print, then whether NRF_LOG_INFO() uses the same UART in ble_app_blinky. To cross check as above, I changed the pin configuration. But still I am seeing debug prints from Development Kit.

a) Whether NRF_LOG_INFO() uses UART. If so what are the pin configurations. Even if I change pins from 5, 6, 7 and 8 to 11, 12, 13 and 14 still NRF_LOG_INFO() prints on Terminal (Using Development Kit).

b) If NRF_LOG_INFO() does not use UART, then how debug prints are printing on Terminal (I am using ‘Tera Term’).

 

4) If I load ‘ble_app_blink’ on Development kit, I am able to see debug prints (Using NRF_LOG_INFO()) on Terminal. But if I load the same on my custom board I could not able to see the prints. In my board, as show above, I am using 11, 12, 13 and 14. Also ‘ble_app_blinky” do not have hardware flow control. So even I disconnected RTS & CTS. But still I am not able to see debug prints.

 

5) Below are the configurations in sdk_config.h. Just I want to print debug prints using NRF_LOG_INFO() on my custom board instead of Development kit (Which is working).

             

#define NRF_LOG_BACKEND_RTT_ENABLED 0
#define NRF_LOG_BACKEND_UART_ENABLED 1
#define NRF_LOG_ENABLED 1
#define NRFX_UART_ENABLED 1
#define UART_ENABLED 1
APP_UART_ENABLED is not defined in sdk_config.h of ‘ble_app_blinky’.

 

Please let me know your inputs and correct me if I am wrong in any of the above statements.

Also please take on priority as I struck up with this issue.

 

Thanks & Regards

Vishnu Beema

[beemavishnu]

Hello Simon,

Thank you for your inputs.

Yes I am trying to implement on my custom board and as you mentioned I changed NRF_LOG_BACKEND_UART_TX_PIN to my required pin and worked fine.

But to get better clarity, please let me know your inputs. Below queries are on Development kit.

2) If there is only one UART, then how to print debug prints and at the same time use UART to communicate with other device (Serial communications).

 

3) If I load ‘ble_app_uart’ example as is into Development kit I am seeing only debug prints in printf() but not in NRF_LOG_INFO(). If both use same UART why debug prints in NRF_LOG_INFO() are not printing.

Thanks & Regards

Vishnu Beema