I have multiple mcu's that are configured to communicate with bus topology. I have 10 pins (4 of them is occupied by now)
I need to debug (update firmware online, etc) all of these mcu's. I read this article but I didn't understand how to achieve the goal.
Question: How can I daisy chain these mcu's?
Debug protocol: SWD
These MCUs support JTAG and SWD. While JTAG supports a daisy chain configuration, SWD does not. There is a multi drop extension in SWD 2.0 protocol, but I am pretty sure your MCU does not implement this.
If you really want to debug multiple chips in a daisy chain, use JTAG. Beware: Tool configuration(s) may be non-trivial to do.
Note that you might want to separate a
firmware updatefrom your
debuggingscenario. Firmware updates can be done in multiple ways using a bootloader, so SWD or JTAG is not required in this case.