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antoine
antoine
Associate III
July 1, 2016
Question

Configuring printf on Keil

  • July 1, 2016
  • 4 replies
  • 6714 views
Posted on July 01, 2016 at 14:30

Hi,

Clearly I'm not the only one who has this need, but the tutorials I followed didn't work for me .

I want to use printf() in Keil, in order to check if my ''DAC to ADC'' code works. I tried with Debug (printf) Viewer in Keil, but I guess it could work with any terminal, I'm not picky.

Apparently it has something to do with rewriting fputc() or putchar().

http://www.keil.com/support/man/docs/ulink2/ulink2_trace_itm_viewer.htm

says to implement the code in the source code, so naively I put it in the main.c, but I guess it's wrong.

If this can help, the goal here is to output a sinewave from the DAC and put it into the ADC. I want to verify the ADC reads it correctly, maybe by printing out values and compare them with the values in the sintable read by the DAC.
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    4 replies

    Nesrine M_O
    Nesrine M_O
    Associate
    July 1, 2016
    Posted on July 01, 2016 at 15:04

    Hi Antoine.PM,

    I recommend you to have a look to the UART example under STM32F4 cube firmware package it may be helpful.

    STM32Cube_FW_F4_V1.12.0\Projects\STM32446E-Nucleo\Examples\UART\UART_Printf

    This example shows how to reroute the C library printf function to the UART. It outputs a message sent by the UART on the HyperTerminal.

    -Syrine-

    antoine
    antoineAuthor
    Associate III
    July 4, 2016
    Posted on July 04, 2016 at 12:09

    Hi,

    Thanks for the links. 

    It seems to work now. I'll try this in context of my real code :)
    Bob Boys
    Bob Boys
    Visitor II
    June 27, 2017
    Posted on June 27, 2017 at 04:22

    Hello

    This is an old posting but it seems many people are having problems getting the keil printf using ITM working.

    This is important method as it does not use a UART or other user hardware in the processor.

    I suspect the usual problem is failing to properly configure Serial Wire Viewer (SWV)

    To configure SWV: See this document page 11: 

    http://www.keil.com/appnotes/files/apnt_286_v1.2.pdf

     

    The Core Clock: setting is important.  Enter the CMSIS global variable SystemCoreClock in a Watch window to get this value.

    You can confirm a CPU clock frequency with this appnote: 

    http://www.keil.com/appnotes/docs/apnt_297.asp

     

    To configure printf the new and easier way:  See page 14 of appnote 286.

    printf on Coretx-M0/M0+:   SWV is only available on Cortex-M3, M4 and M7 and the upcoming M23 and M33.

    There is a way the implement this printf with a Cortex-M0, M0+:  in the appnote above, instead of selecting STDOUT ITM, select EVR.

    Add these lines to your file containing your main() function:

    #include 'EventRecorder.h'                       // Keil::ARM_Compiler  EventRecorderInitialize (EventRecordAll, 1);  // initialize and start Event Recorder

    These are described here: 

    http://www.keil.com/support/man/docs/uv4/uv4_db_dbg_evr_setup.htm

     

    I will work these directions out later in more/less detail and update appnote 286.

    Thanks

    Bob Boys

    ARM

    Bob Boys
    Bob Boys
    Visitor II
    July 1, 2017
    Posted on July 01, 2017 at 04:21

    Hello

    It is possible to use the new Keil uVision Event Recorder to implement a printf that does not require a UART or Serial Wire Viewer.

    You can use Event Recorder to annotate your own source code.

    http://www.keil.com/pack/doc/compiler/EventRecorder/html/index.html

    This will also work with other Cortex-M processors.

    Attached is an updated version of the Keil ST-Link appnote. I will put this on Keil.com early next week:

    Bob

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