I've searched the forums and tried and failed on my own several times.

It appears to me that true debugging on the LPC1768 mbed is not possible. Search the forums and you'll find the common theme that while drag-n-drop takes seconds to program, doing the same with the CMSIS-DAP interface takes many minutes, or fails. Single-step takes 5 to 50 seconds, or fails.

Is there a solution to this, aside from abandoning the original mbed platform?

• https://os.mbed.com/handbook/HDK-and-CMSIS-DAP

• https://os.mbed.com/forum/mbed/topic/27678/
• https://os.mbed.com/forum/bugs-suggestions/topic/27828/?page=1#comment-52971
• https://os.mbed.com/questions/68973/LPC11U35401-interface-with-LPC-1768-targ/

I use Eclipse (or Qt Creator) as IDE and pyOCD as GDB server to debug mbed LPC1768 offline on a Windows 7 (32-bit) system. It's quite fast with MBED OS 2 but a bit slower with MBED OS 5 (especially the execution of Thread::wait() function). Nevertheless, it works and I think it's usable. It takes about ten seconds to flash the board and a fraction of second to switch a DigitalOut pin or to execute a printf() function during debugging. What takes much more time than suppose to is the execution of Thread::wait() function.

• https://os.mbed.com/forum/mbed/post/53903/
• https://os.mbed.com/users/hudakz/notebook/building-offline-with-qt-creator/