How to enable debug output in mbedtls_selftest sample?

[TomGibson]

I am attempting to find out how to enable mbedtls debug output, I have imported the mbedtls_selftest sample to mcuxpresso and in the mbedtls/include/port/ksdk/ksdk_mbedtls_config.h uncommented the #define MBEDTLS_DEBUG_C line. I have also called mbedtls_debug_set_threshold from my main function. However, at no point during execution of the code sample does mbedtls_debug_print_msg appear to be called. Despite defining MBEDTLS_DEBUG_C the IDE still greys out most of the contents of mbedtls/library/debug.c. What am I missing, why is defining MBEDTLS_DEBUG_C and setting the output level not enough to generate debug output?

[Alice_Yang]

Hello @TomGibson 

Please run the mbedtls_selftest example by default, without any change, open a terminal on PC,

you can see the debug log.

Also you need confirm connected to the right UART port. You can see readme.txt under project , and check from below codes in main() function:

BOARD_InitBootPins();

BOARD_InitDebugConsole();

BR

Alice

[TomGibson]

Thanks for your reply @Alice_Yang.

I can already see the output you mention from mbedtls_printf in the UART, the issue is that I have set the debug threshold via the appropriate library function and defining the appropriate constant in the KSDK MbedTLS config file, but this does not appear to enable the mbedtls debug output from within the library itself (the debug output is not the same as the printfs I can see on the UART which the code sample sends and all originate in the selftest.c file).

Enabling the debug output should mean the library prints appropriate debug/trace messages from its internal code via the MBEDTLS_SSL_DEBUG_MSG macro, but this function appears to never be called and the IDE editor appears to show that it is not enabled despite my defining MBEDTLS_DEBUG_C in the header file mentioned above.

[Alice_Yang]

Hello @TomGibson 

About MBEDTLS usage, how about ask help from arm MBED-TLS:

https://www.arm.com/technologies/mbed-tls   

BR

Alice