How to use Eclipse and GDB to debug the .NET Micro Framework

In my last post we were using GCC to build the .NET Micro Framework firmware for the i.MXS reference board. Now we go one step further and will debug the firmware using GDB.

What do we need?

• GDB and GCC - it's included in the free ARM Tools from Raisonance
• OpenOCD and a JTAG Debugger (e.g. ARM-USB-OCD)
• Eclipse as an IDE (with CDT plugin)
• Zylin-embedded CDT (the update site for Eclipse is: http://opensource.zylin.com/zylincdt)

First an overview of our setup:



The installation should be straight forward. Here are the configuration steps...

• Open a command window, invoke setenv_gcc.cmd and run Eclipse from this initialized build environment.
  
  
• Create a new C++ Project in Eclipse:
  
  File->New->C++ Project
  
  
  
  (I set the workspace to "C:\" and named the project like the installation directory of the porting kit "MicroFrameworkPK_v3_0".)
  
  
• Configure Build:
  
  Project->Properties->C/C++ Build
  Add a new configuration e.g. "iMXS Debug RAM"
  Build command: msbuild.exe
  Build directory: ${workspace_loc:/MicroFrameworkPK_v3_0/Solutions/iMXS}
  
  
  
  Build (Incremental build): dotNetMF.proj /t:build /p:flavor=debug;memory=ram;platform=iMXS
  (This builds a debug version of the iMXS firmware that executes from RAM. To build a release version that executes from FLASH, don't add any additional arguments after dotNetMF.proj)
  
  
  

• We add OpenOCD as an external tool:
  
  Run->External Tools->External Tools Configuration...
  Name: OpenOCD
  Location: C:\Program Files\openocd-r247\bin\openocd-ftd2xx.exe
  Working Directory: C:\Program Files\openocd-r247\bin\
  Arguments: -f imxs.cfg
  (For a sample imxs.cfg file look here.)
  
  
  
  
• Finally we configure gdb:
  
  Run->Debug Configurations...
  Add "Zylin Embedded debug (native)" configuration
  Name: iMXS tinyclr
  C/C++ Application: C:\MicroFrameworkPK_v3_0\BuildOutput\ARM\GCC4.2\RAM\debug\iMXS\bin\tinyclr.axf
  
  
  
  GDB Debugger: C:\Programs\Raisonance\Ride\arm-gcc\bin\arm-none-eabi-gdb.exe
  
  
  
  Initialize commands:
  
  target remote 127.0.0.1:3333
  monitor reset
  monitor sleep 500
  monitor poll
  monitor soft_reset_halt
  monitor arm7_9 sw_bkpts enable
  break PreStackEntry
  load
  continue
  
  (This connects to the gdb server, enables software breakpoints, sets a breakpoint at the function PreStackEntry, loads the firmware into RAM and starts... )
  
  
  
  
• Now we can settle back and only press some buttons...
  
  First we build a debug version that executes from RAM
  
  
  
  
  
  
  
  ...run our JTAG server OpenOCD
  
  
  
  
  
  
  ...and hit the debug button!
  Now it takes some seconds to transfer our debug firmware into the RAM of the i.MXS board.
  
  
  
  The firmware starts and immediately stops at PreStackEntry. Now we can discover the code line by line... :)