We have multiple STM32 uC on board and would like to share as many connections for programming the parts.

JTrau.1 · ‎2020-09-02

Is there a way to connect them in parallel with some individual enable to reduce the outward interface of the board. ie maybe connect everything in parallel except for RST line or ??? any suggestions would be appreciated

Tesla DeLorean · ‎2020-09-02

JTAG would at least provide a means to test the PCB and chips, and selectively debug the application over multiple MCUs.

The ability to debug and bring-up the board need to be strong considerations in initial development, easy to build a board that's near impossible to debug on.

Tips, Buy me a coffee, or three.. PayPal Venmo
Up vote any posts that you find helpful, it shows what's working..

JTrau.1 · ‎2020-09-03

Ya, this is what i was thinking and why I shy'd away from it

waclawek.jan · ‎2020-09-03

> Could mux TX outputs with diode tree and pull-up

But why? As you've said, selectively hold devices in reset, then the only active Tx is the one which is not in reset, thus they can be tied together. Rx and BOOT0 all can naturally be tied together, so one only needs to have separate resets. That's IMO a quite minimalistic setup.

Did I overlook something?

JW