Should pyOCD work with mDot on UDK2

[Shaun Nelson]

I’ve just installed pyOCD but cannot get it to work with mDot on a UDK 2.0
Specifically, pyOCD does not see it as a connected board.

I have an LPC1768 lying around and pyOCD works like a champ with it. When I plug in this device an MBED CMSIS DAP USB Device is added. When I attach the mDot on UDK2 an STM32 STLink USB Device is registered.

I know pyOCD uses the CMSIS-DAP interface, so is there a way to gain access to the mDot’s when on an UDK board?

Thanks,
-Shaun

[Andrew Lindsay]

Perhaps this is a question for the pyOCD community rather than the mDot community.

Andrew

[Mike Fiore]

Shaun,

It doesn’t look like pyOCD has support for very many ST targets yet.

https://github.com/mbedmicro/pyOCD/blob/master/pyOCD/board/mbed_board.py

The mDot has a STM32F411 processor, which isn’t in that list. You could try adding it if you wanted.

However, OpenOCD does have support for ST targets. I was able to start a gdb session to debug my mDot by following these steps:

* download OpenOCD from https://sourceforge.net/projects/openocd/files/openocd/0.9.0/
* extract tarball
* run configure; make; sudo make install
* add self to plugdev group (linux)
* copy /usr/local/share/openocd/contrib/99-openocd.rules to /etc/udev/rules.d/ (linux)
* connect USB from UDK2
* run openocd -f /usr/local/share/openocd/scripts/interface/stlink-v2.cfg -f /usr/local/share/openocd/scripts/board/st_nucleo_f4.cfg
* in another terminal, run arm-none-eabi-gdb
* in the gdb prompt, type target remote localhost:3333

Documentation for OpenOCD 0.9.0 is here:

http://openocd.org/doc-release/pdf/openocd.pdf

Make sure your application (and the mbed libraries) were built with debug symbols!

Hope this helps!

-Mike

[Shaun Nelson]

Hi Mike,

Thanks for the info. I’ll give OpenOCD a shot.

Regards,
-Shaun

[Mike Fiore]

Shaun,
I realized the info I gave you was incomplete. Here’s an updated series of steps to debug your mDot:

* download OpenOCD from https://sourceforge.net/projects/openocd/files/openocd/0.9.0/
* extract tarball
tar -xzvf openocd-0.9.0.tar.gz
* make and install OpenOCD
configure; make; sudo make install
* add self to plugdev group (linux)
sudo usermod -a -G plugdev
* copy udev rules for debug interfaces (linux)
cp /usr/local/share/openocd/contrib/99-openocd.rules to /etc/udev/rules.d/
* connect UDK2/MDK/etc
* start openocd
openocd -f /usr/local/share/openocd/scripts/interface/stlink-v2.cfg -f /usr/local/share/openocd/scripts/board/st_nucleo_f4.cfg
* start gdb in another terminal
arm-none-eabi-gdb
* connect your gdb instance to the gdbserver OpenOCD is running
(gdb) target remote localhost:3333
* load the symbol file into gdb – this is the .elf file in the same directory your binary was in
(gdb) symbol-file * halt and reset the target
(gdb) monitor reset init
* now you’re ready to debug!

Make sure your application (and the mbed libraries) were built with debug symbols! The simplest way is to use the “-o debug-info” with the build and make scripts.

Also, here’s a good tutorial I found:

http://mcuoneclipse.com/2015/03/22/openocdcmsis-dap-debugging-with-eclipse-and-without-an-ide/

Cheers,

Mike

[Shaun Nelson]

Hi Mike,

OpenOCD works great!

I did hit a speed bump on the configure/make step. It seemed to build fine but OpenOCD could not find the debug interface; the exact error was “specified debug interface was not found (hla).

Looking in the configure log there was an error that libusb-1.0.x was missing, which apparently is not enough to abort the make (don’t you love silent failures!). I fixed this with ‘apt-get install libusb-1.0.1-dev.

When I ran configure the 2nd time I also passed in –enable-stlink because I read on a forum that perhaps the interface support was not compiled in.

As a final step to confirm OpenOCD was properly configured, I ran ‘openocd -c interface_list’ and voila hla was in the list.

Thanks again,
-Shaun

[Mike Fiore]

Shaun, excellent! I’m glad that worked out for you.

Happy debugging!

-Mike

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