Kinetis FRDM-KL25Z with external debugger

Here is how to attach external debugger to Kinetis CPU on FRDM-KL25Z board. Like we are used to by now the debug connector on the boards with an on-board debugger is used to connect the on-board debugger to board without it. Anyway the debug connector can be used as input when on-board debugger is put in reset. This is done with jumper on the other debug connector. I.e. on the debug connector for the on-board debugger (debugging a debugger - there's a thought for you :) ).

You might need to chip away a bit of debug connector housing due to C7.
Probably not if you are just using pinheader.

STM32F4DISCOVERY Eval board with external debugger

I got the STM32F4DISCOVERY demo board at Embedded World last week. To my surprise the SWD  (single wire debug) connector is not meant for external debugger. In fact it is the other way around. The board can be used  as debugger to debug designs without on-board debugger.

I wanted to attach my debugger anyway. To disable the on-board debugger I hold it in reset by connecting it's reset signal to GND via SB10. To make it reversible I added jumper over SB10 solder jumper.

The external debugger can measure the VDD pin voltage for target detection. *

Single wire output (SWO) trace can be used when using the SWD. * NOTE: this is for trace only - not needed for (invasive) debug.

Even old style JTAG scan debugging is possible (it can be faster) if additional TDI signal is connected. It is at PA15. NOTE: SWO can't be used with JTAG.

Parallel trace on pins PE2 - PE6 is an option when JTAG is used * - not shown on photos.

* -  if supported by external debugger

[Update] See how STM32F4DISCOVERY can be used as free debugger.

Kinetis KwikStik upgrade for external debugger

I have modified the KwikStick evaluation board to be able to attach external debugger. Of course connector was soldered. The board has a place for a 1.27mm (50 mil) pitch 10 pin SMD Cortex debug connector. Additionally I have added the jumper to connect integrated J-Link reset line to ground. This way on board debugger will definitely keep it's IOs in state of high impedance.