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SWD multidrop? Does any STM32 or ST-LINK support it?

Forum|Forum|3 years ago
January 10, 2023
3 replies
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Found this feature mentioned in Segger J-LINK wiki, but it is not clear which targets support it:

https://developer.arm.com/documentation/ddi0314/h/Debug-Access-Port/SW-DP/SW-DP-multi-drop-support?lang=en

It looks like a cheap alternative of JTAG chain. From the description, I don't understand can this multidrop be done outside of a MCU chip (allows to connect several STM32s thru one ST-LINK attachment) or it refers to cores inside one MCU?

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Best answer by Peter BENSCH

No, this has nothing to do with multicore, the F7 and other single cores also contain SWD protocol version 2 and can Multi-Drop. However, as far as I know, ST-LINK does not support this at present.

Regards

/Peter

Peter BENSCH

ST Technical Moderator

Hi Pavel,

yes, Multi-Drop is supported in some families and has already been discussed, see here and there.

Regards

/Peter

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Pavel A.Author

So does this refer to multiple cores in a package (such as multicore H7 or wireless) or several MCUs can be connected 'passively' to one ST-LINK?

Peter BENSCHBest answer

ST Technical Moderator

No, this has nothing to do with multicore, the F7 and other single cores also contain SWD protocol version 2 and can Multi-Drop. However, as far as I know, ST-LINK does not support this at present.

Regards

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.