How to deal with SWD frequency

[CZT-PAM]

Hi guys,

I have to work on a custom board (base on a STM32F103VDT6), which has large capacitors on SWCLK and SWDIO. So, it limits the SWD frequency capability.
For example, with CUBEProgrammer and a STLINK-V3, I can connect the MCU with a 1MHz SWD frequency, but it does not work at 8MHz.
With STM32duino, default SWD frequency is 8MHz. How can I change it ?

Thanks,

[fpistm]

Hi @CZT-PAM
Arduino IDE 2 uses Marus Cortex debug extension.
When you launch the debug, a launch.json is created.
So, as specified in the documentation of the extension:
https://github.com/Marus/cortex-debug/blob/master/debug_attributes.md

I would try to do add this in this launch.json:

      "swoConfig": {
        "swoFrequency": 1000000,
      }

Pay attention, Arduino IDE 2 regenerate this file each time you launch the debug from the toolbar button

To be able to use the new settings you have to use the Start debugging from the Debug extension :

I didn't test, let me know if it works.

[CZT-PAM]

Hi, thank you for your feedback.

The "swoConfig" update in the launch.json works:

I also verified it using a scope.

But, it update the SWD frequency only for debugging.
I need to manage frequency for the upload too, it still 8MHz for now.

May be I have to change/add option to platform.txt, but It remains unclear to me.

[fpistm]

Sorry, thought it was for debug.
For upload method, the only way I found is to edit the dtm32CubeProg.sh script to add the desired freq after the interface settings port=SWD.
https://github.com/stm32duino/Arduino_Tools/blob/8017b405abf5534cb34afdf78184be14bf371607/stm32CubeProg.sh#L223

-    ${STM32CP_CLI} --connect port=SWD mode="${MODE}" "${ERASE}" --quietMode --download "${FILEPATH}" "${ADDRESS}" --start "${START}"
+    ${STM32CP_CLI} --connect port=SWD freq=1000 mode="${MODE}" "${ERASE}" --quietMode --download "${FILEPATH}" "${ADDRESS}" --start "${START}"

The STM32Cube programmer cli uses positional arguments so can't simply add it as an extra option using the (boards/platform).local.txt feature. (See https://arduino.github.io/arduino-cli/0.30/platform-specification/#platformlocaltxt)

This could be added as a new argument of the script then by default freq will be set to 8KHz if not specified.
Like this any board can redefine it in the boards.txt or thanks teh boards.local.txt.
If you think it is useful feature feel free to open an issue and/or provide a PR 😉

[CZT-PAM]

Hi Guys,

Update the dtm32CubeProg.sh looks the right solution !

Thank you for you support.
If other people had the same problem it could be useful to open an issue or provide a PR. But I think the problem mainly comes from my old custom board initially(developed with a ST Link V1 with low speed SWD).

[fpistm]

OK. Thanks for the feedback. I keep in mind this when I will update the script.