JTAG chain

[IMor.1]

I design new design with 4 STM32 MCUs, if I daisy chain all together,

1. Can I debug two MCUs at the same time?
2. from your expirience what the maximum clock with 4 MCUs
3. Do I need to add clock buffer on the TCK ?

[Uwe Bonnes]

1. I do not know of any debugger yet capable of that
2. Normally maximum speed it not the problem, but excessive reflections depending on setup. I debugger is connected via cable, more reflections are to be expected. If the debugger uses great drive strength and high slew rates, more reflections are to be expected. Otherwise debugger speed only counts if mauch data is transferred, flashing is mostly limited by the device itself
3. See 2. I think only needed in corner cases