AnsweredAssumed Answered

No traceswo output on stm32H7xx

Question asked by Florian Otte on Mar 16, 2018
Latest reply on May 18, 2018 by Clive One

Hi Forum. I am new to the H7 line of processors and the first thing I tried is getting printf() output on the traceswo pin of my nucleo-H743ZI. What I have tried:


1. The 'Everything out of the box' way:

Use cubeMX to configure sys to async trace, configure clocks, enable master clock out (to verify clock speed with a logic analyser).

Import the project to atollic truestudio and configure debugging to use the SWV, with the specific baudrate and core clock.

Write simples mainloop:

while(1) {




Start a debugging session, configure trace port 0 and start tracing -> no output in atollic truestudio, no output on PB3 (verified with logic analyser)


2. The 'Do some manual work and hope the rest will resolve' way:

Same as above, with the exception of enabling the ITM unit manually:

CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;
CoreDebug->DEMCR |= CoreDebug_DEMCR_VC_CORERESET_Msk;

ITM->LAR = 0xC5ACCE55; // Unlock Lock Access Registers
ITM->TER |= 0x01; // Port 0

Start debug session, enable tracing in atollic studio, THEN call my own init function - since the debugger overwrites the register values -> No traceswo output


3. The 'Do another variation of the non-working example' way:

Same as above, but I let the debugger handle the initialization and have the processor my init code before tracing is enabled through atollic stuido

-> Same result



4. The 'Try to do it by the book' way:

Here I really failed. What I tried:

Configure ITM manually, configure the SWO and SWTF unit manually.

Here my problem is that I do not know where SWO and SWTF are found in memory. The reference manual tells me that I can look up these adresses through the System ROM tables at adress 0xE00E0000.


However acessing these yields a fault -- Have not implemented the different faults, so i can not tell which is the one thats biting my ***! So I thought: Maybe I need to access these in priviledged mode.. same error.


(Atollic truestudio version - if that matters):

Atollic TrueSTUDIO® for STM32, Built on Eclipse Neon.1a.

Version: 9.0.0

Build id: 20180117-1023




Has someone a working example for trace output on the traceswo line on the nucleo-h743zi using atollic truestudio?

Any help or suggestions are apprechiated!






I received a response from Atollic.


XXXXX XXXXXXX (Atollic Support)

Mar 16, 09:17 CET

Dear Florian,

There is a known problem with the STM32H7 which we have a ticket for at the moment. We hope to have this fixed until the next release. However, we haven't had a response from the correct ST department just yet if there's a problem with the MCU itself or if we've made a faulty configuration in the software somewhere. We're going to try to reach out again for a response.

Best regards
XXXXXX, Atollic Support Team