1 year, 9 months ago.

pyOCD Exception while probing AP#0


I'm trying to "unbrick" a FRDM-K66F DAP interface (MK20DX128VFM5), using a FRDM-K64 as a CMSIS-DAP debugger. I have followed the steps above, but encounter the following error when running pyOCD:

pyOCD Error

 ERROR:root:Exception while probing AP#0: TransferError()
Traceback (most recent call last):
  File "C:\python37\Scripts\pyocd-flashtool-script.py", line 11, in <module>
    load_entry_point('pyOCD==0.12.0', 'console_scripts', 'pyocd-flashtool')()
  File "C:\python37\lib\site-packages\pyOCD\tools\flash_tool.py", line 137, in main
    frequency=args.frequency, blocking=False)
  File "C:\python37\lib\site-packages\pyOCD\board\mbed_board.py", line 222, in chooseBoard
  File "C:\python37\lib\site-packages\pyOCD\board\board.py", line 50, in init
  File "C:\python37\lib\site-packages\pyOCD\core\coresight_target.py", line 126, in init
  File "C:\python37\lib\site-packages\pyOCD\utility\sequencer.py", line 189, in invoke
    resultSequence = call()
  File "C:\python37\lib\site-packages\pyOCD\target\family\target_kinetis.py", line 81, in check_mdm_ap_idr
    self.mdm_ap = self.dp.aps[1]
KeyError: 1

Any ideas what could be causing this? I have ensured that JTAG connections are pin-to-pin and J8 jumper on the FRDM-K66F has been cut.

Thanks, Tom

Question relating to:

1 Answer

1 year, 8 months ago.

Hi Tom,

It would appear that the Debug Access Port (DAP) is in a bad state but we have no way of knowing why! We suggest you contact NXP support or post on their forums to see if they have any insight into the problem.

Sorry that we can't be more helpful.


Ralph, Team Mbed