Resistor in STM32F103's two-pin SWDIO setup.

[jeru]

I'm not sure whether
mbed-HDK-Eagle-Projects is synced with ARMmbed/DAPLink at all. So maybe I'm simply holding a wrong assumption to start with...

But if they are supposed in sync, something confuses me:

1. I can find two designs of STM32F103 boards in mbed-HDK-Eagle-Projects, one is STM32-DIPDAP, one is DAPule-STM32F103.
   • Key point I want to make: PB12 connects to TGT_SWDIO with an 100R resistor, PB14 directly connects to TGT_SWDIO.
     
2. In ARMmbed/DAPLink, by IO_config.h, the out pin is PB14 and the in pin is PB12.
   

So if we use the firmware directly on either board:

• PB14 as output is connected TGT_SWDIO, meaning if the DAPLink decides to pull HIGH but the target board decides to pull LOW (like in a buggy or target-board-broken situation), something is going to fry.
• PB12 is already in input mode so already high-impedence. Adding 100R doesn't make a change?

Any chance the two pins are accidentally swapped somehow? Or I have missed something trivial (not professional in embedding)? Thanks.