stm32f769 discovery printf and ITM_SendChar

[Kyrpav]

I have made an project from touchgfx and opened it from subeide.

The project is loading normally and i have overwritten the write function:

/* USER CODE BEGIN 0 */

int _write(int file, char *ptr, int len)
{
    int DataIdx;
    for (DataIdx = 0; DataIdx < len; DataIdx++){
        ITM_SendChar(*ptr++);
    }
    return len;
}
/* USER CODE END 0 */

in the main default task i have a toggle pin function that works and before the toggle a printf.

i have enabled the SWO from the debugger configuration and the clock is exactly as in the ioc file 216Mhz
When opening the debugger i select port 0 in the SWV console. The system has by itself a prescaller to 108 which i can not edit and the SWO clock is 2000.

There is nothing printed in the port 0 . I have placed an interupt in the function above to ensure that printf really calls the write function. This is true it uses the write function but ITM_SendChar does not do anything,

[Tesla DeLorean]

Make sure there's not a Solder Bridge you need to make for PB3/SWO pin

Use STM32 Cube Programmer SWV Viewer, or that of the ST-LINK Utilities

Try the ITM_SendChar() outside of printf()

Try running the STM32F7 from HSI, and use THAT clock frequency.

Check ITM TCR / TER bits, perhaps unpack the SWO baud divider

printf("\n\nCore=%d, %d MHz\n", SystemCoreClock, SystemCoreClock / 1000000);

TPI->ACPR is the divider on the CM7's = (SystemCoreClock / (SWCLK * 2)) - 1 if I recall

ITM->LAR = 0xC5ACCE55; // Unlock on the CM7's

[Kyrpav]

Which solder bridge do you refer i do not see any comment about a solder bridge for PB3 and SWO in the UM2033
User manual for the Discovery kit with STM32F769NI MCU i can not find by search or by reading it anything about SWO?

I tried ITM_SendChar outside the printf and it does not print. I saw in debug that the string sent ITM_SendChar is there and the pointer moves one to one to the letters.

Currently the clocks are set like in the screen from Touchgfx. What do you propose to change?

I have previously tried to set the ITM->LAR though i was not sure what it does and it did not do anything. Not the ACPR the lar and somethings else. If you can give some correct lines of code i can place them to a function to check if they help.

I have a nucleo board H755ZI and there only by adding the _write function and enabling the asychronous trace sw it works. in this board it does not.

Thank you.

[Kyrpav]

Discovery kit with STM32F769NI MCU
Introduction
The 32F769IDISCOVERY Discovery kit is a complete demonstration and development
platform for STMicroelectronics Arm® Cortex®-M7 core-based STM32F769NIH6
microcontroller. It features four I2Cs, six SPIs with three multiplexed simplex I2S,
2xSDMMC, four USARTs, four UARTs, three CAN buses, three 12-bit ADCs, two 12-bit
DACs, two SAIs, internal 512+4-Kbyte SRAM and 2-Mbyte flash memory, USB HS and FS
OTGs, Ethernet MAC, FMC interface, Quad-SPI interface, and SWD debugging support.

The do not have anything else about SWO and they have only 2 pins for the clk and the swdio in the pin explanation. In the ioc at the pin PB3 you can see the function to select and as i said it is automatically set if you select Trach asynchronous SW.

Is it possible that it does not work?

[Tesla DeLorean]

I mean check the schematic, some of the DISCO boards have solder bridges in the signal path, I'm saying make sure your board (model/revision) does not

https://www.st.com/en/evaluation-tools/32f769idiscovery.html

https://www.st.com/en/evaluation-tools/32f769idiscovery.html#cad-resources

https://www.st.com/resource/en/schematic_pack/mb1225-f769i-b02_schematic.pdf

Yours has a Resistor and SB21, the default path is too the MicroSD socket SDIO/SDMMC2, needs to be switched over so there is a conductive path for the signal to get into the ST-LINK T_SWO pin

[Kyrpav]

You mean to desolder R92 if you mean this then it is probably impossible in the process I will probably damage the PCB. I will use uart instead if this is the case