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No display of printf() function in debug(printf) viewer

Hi,

I am working on ARM Cortex M4 with 'SWD' debugger. I have printf statements in my program but when executed there is no output displayed in the 'Debug viewer'

I have tried selecting the components STDERR, STDIN and STDOUT to ITM but no result.

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Robert Rostohar over 4 years ago in reply to Westonsupermare Pier +2 verified

There is no need to manually retarget fputc() to ITM when using the Compiler I/O retarget component. See: www.keil.com/.../_retarget__examples__i_t_m.html You need however to properly configure SWO trace...
Westonsupermare Pier over 4 years ago +1 suggested

Yes, probably because you haven't added any code to have fputc() and _ttywrch() call ITM_SendChar(). You likely need to do the plumbing. If you stop in the debugger, is it on a BKPT instruction? ...

0 Westonsupermare Pier over 4 years ago

Yes, probably because you haven't added any code to have fputc() and _ttywrch() call ITM_SendChar().

You likely need to do the plumbing.

If you stop in the debugger, is it on a BKPT instruction?

Does the core speed in the Trace options window match that of the processor, and have you enabled/disabled the other options appropriately?
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+1 Robert Rostohar over 4 years ago in reply to Westonsupermare Pier

There is no need to manually retarget fputc() to ITM when using the Compiler I/O retarget component.
See: www.keil.com/.../_retarget__examples__i_t_m.html

You need however to properly configure SWO trace. It might be that your setup is not correct.

Example for ULINKplus Trace configuration:
www.keil.com/.../ulinkplus_ctx_trace.htm

Check setting for Core/Trace Clock, Trace Enable (on), Trace Port (SWO) and SWO Clock, ITM Port 0 (on).

While running check the Trace Status which should be Running ...
www.keil.com/.../ulinkplus_trace_status.htm
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0 Ambrosio over 4 years ago in reply to Robert Rostohar

Hi Robert,

Thanks for the solution.

I am getting error

Following are my Trace settings
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0 Robert Rostohar over 4 years ago in reply to Ambrosio

Typically debuggers first interrogate the device ROM table to identify the debug infrastructure supported by the implementation.

It seems that your device does not have all the required debug components for trace: DWT, ITM, TPIU.

Are you using a custom Cortex-M4 without TPIU (Trace Port Interface Unit) which is optional?
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