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"Timeout waiting for gdb server to start" when trying to debug

Trying to start debugger, blinky example program, FRDM-K64 board. I get “Timeout waiting for gdb server to start”.

EDIT: found more info. I looked through the Mbed Studio log file, and saw that it is calling pyocd-gdbserver with these arguments:

“gdbServerArguments”:[“gdbserver”,"–uid",“000059305636”,"–target",“MK64FN1M0xxx12”,"–erase=chip","–pack",“c:\Users\Mike\AppData\Local\Mbed Studio\mbed-studio-tools\cmsis-packs\Keil.Kinetis_K60_DFP.1.5.0-small.pack”]

So I tried running pyocd-gdbserver manually with those arguments and I get:
error: unrecognized arguments: --uid 000059305636 --erase=chip

If I remove those two arguments above, it runs, but I get:

"WARNING:gdb_server:pyocd-gdbserver is deprecated; please use the new combined pyocd tool"

It looks like when I installed Mbed Studio it installed an older version of pyocd-gdbserver(?) But if do: Help–>Check for tools updates it shows that all my tools are up to date.

EDIT: I am using a Segger J-Link debug probe.

Hi @mecono,

Unfortunately, using Segger J-Link with Mbed Studio is not currently supported. Have you tried connecting directly to the K64F board using micro-usb?


Matthew Gordon
Mbed Studio team

1 Like

Thanks for the quick reply. We are actually developing a custom board/assembly that is based on the K64F board SWD interface alone. We are using Mbed in our move from the current custom OS. What is the most common debugging configuration that is used? Thanks.

Hi @mgordon01, thanks for your reply. Actually as @sklatham94 mentioned our board is similar to FRDM-K64F but not identical. I was just using FRDM-K64F as a starting point for debugging.

So, which Debug probes does Mbed Studio support? For me it is a must to have a JTAG probe connected via the 10-pin header. On our custom board micro-USB is not an option.



Hi @mecono & @sklatham94,

Mbed Studio officially supports debug using the built-in interface chips on these development boards:

We do not test with individual debug probes, but Mbed Studio’s debug support is powered by pyOCD so you may make progress with the probes on this list:

Hope that helps,