Arm Mbed OS support forum

Pyocd errors on programming and debugging of STM32F746

I’m running Mbed Studio 1.3.1 with STM32F746DISCOVERY board. Pyocd errors with both programming and debugging of this board. Programming defaults to mass storage interface and still works but debugging obviously not. This board is listed on Mbed web site as supporting debugging, The following is an error log:

root/mbs-deploy - 0001148:ERROR:rom_table:Error attempting to probe CoreSight component referenced by ROM table entry #0: 
SWD/JTAG Transfer Fault @ 0xe000efbc-0xe000f043
pyocd.core.exceptions.TransferFaultError: SWD/JTAG Transfer Fault @ 0xe000efbc-0xe000f043
0001168:CRITICAL:__main__:No cores were discovered!

Any help much appreciated.


I can agree that but this target was silently removed from the list of supported boards for debug.

BR, Jan