Cant get J-Link RTT Viewer to show log information

Question

Hello again Nordic Pros, 
 I am trying to get some debug logging going using the 52DK running ble uart central under SDK 12.3 and RTT Viewer v6.4. 
 I have setup config.h as such: 
 
 and added this line to test getting a log with each RX event: 
 
...
 case BLE_NUS_C_EVT_NUS_RX_EVT:
 NRF_LOG_DEBUG ("TEST!
");
... 
 Yet there are no logs in any RTT Viewer Window when characters are sent via BLE. 
 What am I missing here? 
 Robin @ TL 
 
 I now have RTT-Viewer showing logs. However, there are 2 problems: 
 1.) If I turn on timestamping, my board hangs, 
 2.) When logging is enabled, I cannot command the board via the terminal. 
 Any suggestions on how to remedy this issues is greatly appreciated! 
 Thanks 
 Robin @ TL

Robin · Accepted Answer

OK, for those who want to know... I have RTT Viewer up and running, even on our 51 based custom board. I am able to log messages while maintaining a UART->BLE->TARGET command/response link up. Here is the test system comm path: 51_based_custom_ble_uart_peripheral<->ble<->52DK_ble_uart_central<->USB_UART<->PC<->termite_terminal: |->RTT_Viewer. Both boards are running under SDK 12.3. Here is what I had to do: 1.) Configure NRF_Logging in config.h: 2.) Add the following preprocessor definition: NRF_LOG_USES_RTT=1 3.) Add the following includes: #include "nrf_log.h" #include "nrf_log_ctrl.h" 4.) Add the following define: #define NRF_LOG_MODULE_NAME "iDrink" 5.) And, finally add the following log initialization macro: NRF_LOG_INIT(NULL); This is an amazing powerful tool for real time debugging in code tracing. I hope this helps someone else in need of such capabilities. Thanks all for your help, Robin @ TL

XavierYin · Answer

If you use NRF_LOG_DEFERRED, log will be processed only when NRF_LOG_PROCESS() or NRF_LOG_FLUSH() is called. They're typically executed in the last loop part in main() as part of idle task. See SDK examples for this. 
 Otherwise, the simplest solution is turn NRF_LOG_DEFERRED off. This makes log processed in-place.

Cant get J-Link RTT Viewer to show log information

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