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

[Pavel A.]

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?

[Peter BENSCH]

Hi Pavel,

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

Regards

/Peter

[Pavel A.]

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 BENSCH · Accepted solution]

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

[Tesla DeLorean]

H5 Supports, https://community.st.com/t5/stm32-mcus-products/does-the-stm32h5-support-multi-drop-swd-serial-wire-debug-v2/td-p/596520

Related  https://community.st.com/t5/stm32-mcus-products/swd-multi-drop-support-on-stm32l4/m-p/80394

[Pavel A.]

Great. Could anybody share success story with the multi-drop? Which debug adapter (as st-links do not support it yet)?