If you have one of our debuggers for card10, this page details how you can use it. The debugger looks like either one in the following pictures:


First of all, you need to connect your debugger and card10. There are three connections that you need (take a look at the above diagram for more info):

  • HDK: This connection provides debugging (SWD) and UART.

  • DEV: This connection provides power (battery charger) and the native USB connection (bootloader).

  • USB-C: Connect the proved USB-C cable with the side which has the blue dot, so the blue dots have the same side.


When using the debugger, you will usually have two /dev/ttyACM* devices (one each for HDK and DEV). To avoid confusion, allow access without sudo and tell ModemManager to ignore them, you can use the following udev rule file (saved under /etc/udev/rules.d/99-card10.rules):

SUBSYSTEM=="tty", ATTRS{idVendor}=="0d28", ATTRS{idProduct}=="0204", MODE="0664", GROUP="plugdev", SYMLINK+="ttyACM-card10-hdk", ENV{ID_MM_DEVICE_IGNORE}="1"
SUBSYSTEM=="tty", ATTRS{idVendor}=="0b6a", ATTRS{idProduct}=="003c", MODE="0664", GROUP="plugdev", SYMLINK+="ttyACM-card10-dev", ENV{ID_MM_DEVICE_IGNORE}="1"

After changing udev rules, you need to tell the udev daemon:

$ sudo udevadm control --reload

Now, additional symlinks (/dev/ttyACM-card10-hdk and /dev/ttyACM-card10-dev) will be created when connecting the card10.


For debugging card10, you need our own fork of OpenOCD. It contains a patch which allows flashing both flash-banks instead of just one. Install it using the following commands:

$ git clone --recursive
$ cd openocd

$ ./bootstrap
$ ./configure --disable-werror


Make sure CMSIS-DAP Compliant Debugger is set to yes (auto) after running ./configure (if it is not, you might need to install libhidapi-dev (Ubuntu)). If you get errors making the documentation you can touch doc/ to skip it and continue with make.

$ make -j8

Please run make install after removing any already installed OpenOCD version. Otherwise please always specify the full path to OpenOCD (the binary is under src/openocd).


If you want to use OpenOCD as normal user, copy contrib/60-openocd.rules into the /etc/udev/rules.d/ directory and run udevadm control --reload afterwards.

GDB (arm-none-eabi-gdb)

Apart from OpenOCD you also need arm-none-eabi-gdb. You should install that package from your distros repositories:

  • Ubuntu (older): gdb-arm-none-eabi

  • Ubuntu (newer): gdb-multiarch

  • Arch: arm-none-eabi-gdb


Run OpenOCD from the openocd/scripts directory in the firmware repository. Call it as openocd -f interface/cmsis-dap.cfg -f target/max32665.cfg. If the debugger and card10 are connected correctly, you should see the following output:

$ openocd -f interface/cmsis-dap.cfg -f target/max32665.cfg
Info : CMSIS-DAP: SWD  Supported
Info : CMSIS-DAP: FW Version = 1.0
Info : CMSIS-DAP: Interface Initialised (SWD)
Info : SWCLK/TCK = 0 SWDIO/TMS = 1 TDI = 0 TDO = 0 nTRST = 0 nRESET = 1
Info : CMSIS-DAP: Interface ready
Info : clock speed 2000 kHz
Info : SWD DPIDR 0x2ba01477
Info : max32xxx.cpu: hardware has 6 breakpoints, 4 watchpoints
Info : Listening on port 3333 for gdb connections

Next, start GDB in parallel and connect it to OpenOCD. You can do this easily if you run GDB from the firmware repository root where we have provided an init.gdb file. Specify -x init.gdb to use this file. Apart from automatically connecting to OpenOCD, this script file also defines a reset command to soft-reset card10.

$ arm-none-eabi-gdb -x init.gdb build/hw-tests/hello-world/hello-world.elf


You will also find the following self-describing gdb files in the firmware root directory, which do not require additional arguments: flash-all.gdb,  flash-bootloader.gdb, flash-both.gdb,  flash-epicardium.gdb,  flash-pycardium.gdb


If you are used to use mon reset halt, be aware that the card10 prototypes do not connect the reset line to the debugger. OpenOCD is configured to only do a soft-reset. This reset only resets the core, but not its peripherals. Our custom reset sets a special bit in the CPU which also resets the peripherals.

You are now connected to card10 and ready to start debugging! If card10 is still running, stop it using

(gdb) mon reset halt

Following that, you can debug as you would normally.