Output debug via printf on a Cortex-M3 CPU, stalls at BKPT instruction + confusion about JTAG and sw ports

Question

I have a Keil ULINK2 USB emulator box attached to the JTAG connector on my board, which is working fine with the Cortex-M3 CPU onboard (TI/Stellaris/LuminaryMicro LM3S seri

Answer 1

SW is a two wire interface that provides access to debugging ports on the device.

Arm have a .pdf about it here:

http://www.arm.com/files/pdf/Low_Pin-Count_Debug_Interfaces_for_Multi-device_Systems.pdf