The title is quite a mouthful, but I wanted to record what it takes to get debugging working in the Eclipse IDE for the ARM Cortex M3, specifically the Luminary Micro LM3S811 evaluation board.

Unfortunately, the state of Cortex M3/LM3S811 support by OpenOCD is not yet at the point where it is smooth. I think the underlying problem is that resetting the LM3S811 is not happening as expected.

1. Go to the YAGARTO website and download/install the components. Note that the website itself states that YAGARTO does not support cortex m3 yet, we are using this site to get most of the other components, including Eclipse and the Zylin CDT extension.
2. Go to the CodeSourcery website and download the Lite (free) version of their GCC compiler (EABI platform). It is a set of command line tools, but we will be integrating them into Eclipse.
3. Go to this site and get the “software-package Version 20080409”. This is the version of OpenOCD that actually works for the LM3S811. The OpenOCD version on the YAGARTO site, although newer, did not work in the following steps. This site is actually very informative and remains the best site for Cortex M3/GNU ARM toolchain info. Unfortunately, it does not talk about Eclipse integration.
4. Configuring Eclipse is complicated by the fact that several sources of information (YAGARTO, etc.) all say slightly different things. I will eventually list out the exact steps, but for the most part follow the HOWTO’s on the YAGARTO site.
5. […more to follow on Eclipse configuration…]
6. I am assuming at this step you can successfully program the main.bin file. The debug step is a bit more complicated, as it is a two part process
   • Run OpenOCD from the External Tools menu, using the .cfg script that is specifically for debugging (as opposed to programming.
   • Run GDB from the Debug menu. Note this was the most confusing part.
     1. Create a configuration under the “Zylin Embedded debug (Native)” option.
        • Main Tab: The C/C++ Application is the main.bin file that was created (from an .elf file) from the build process using a Makefile.
        • Debugger Tab: Browse for the CodeSourcery GDB file. The default location is C:\Program Files\CodeSourcery\Sourcery G++ Lite\bin\arm-none-eabi-gdb.exe
        • Commands Tab: Here is the key part. Use the following commands, taken from a variety of sources. Again, since resets don’t work properly for the LM3S811, most lines other than the first and last are useless. Note the symbol-file command should be to the .elf file, not the .bin or .sym file.
          • Initialize: target remote localhost:3333
            monitor reset
            monitor sleep 500
            monitor soft_reset_halt
            symbol-file “C:\\PATH\\main.elf”
          • Run: hbreak main.c:38
        • What is going on in the hbreak command is that a hardware breakpoint is being set at a particular line number in main.c. Hardware because software breakpoints don’t seem to work on embedded targets (I could be wrong here). This ugly manual setting is because the reset/halt/init mechanism doesnt work, so without manually setting a break point “Debugging” programs actually lets the program run without stopping.
        • Note this means you need a separate Debug configuration for every subproject/program. This is definitely a pain, but as far as I know the only way you can start debugging at an arbitrary point in the source code. Note that single stepping works well, if slowly.

BTW, the errors involved in resetting and halting the LM3S811 are shown below


Open On-Chip Debugger 1.0 (2008-04-09-14:00) svn:
$URL: http://svn.berlios.de/svnroot/repos/openocd/trunk/src/openocd.c $
Error: jtag.c:927 jtag_add_reset(): BUG: transition of req_tlr_or_trst and req_srst in the same jtag_add_reset() call is undefined
Warning: jtag.c:1197 jtag_check_value(): value captured during scan didn't pass the requested check: captured: 0x0f check_value: 0x01 check_mask: 0x0f
Warning: jtag.c:1157 jtag_read_buffer(): in_handler reported a failed check
Error: jtag.c:927 jtag_add_reset(): BUG: transition of req_tlr_or_trst and req_srst in the same jtag_add_reset() call is undefined
Warning: jtag.c:1197 jtag_check_value(): value captured during scan didn't pass the requested check: captured: 0x0f check_value: 0x01 check_mask: 0x0f
Warning: jtag.c:1157 jtag_read_buffer(): in_handler reported a failed check
User: target.c:382 target_process_reset(): Timed out waiting for halt after reset

I have finally gotten a reverse proxy app to work on the Windows Server 2003 machine.

The solution:

1. Install cygwin. This by far was the biggest stumbling block, as I didn’t want to install cygin on a production server. However, after scouring the web (and google) for free/open source reverse proxy apps for Windows, I came to the conclusion that the only ones available require cygwin.
2. Get Pound. I’ve looked at a variety of reverse proxys (nginx, lighttpd, apache, etc.) and each one seemed to have some disadvantage that I couldn’t ignore. Not to mention many of the alternatives weren’t dedicated reverse proxys but web servers. More details are here.
   • One caution is that the most recent version of pound (2.4.2) would not compile, as it required some IPv6 support in the headers. I chose to download the previous version (2.3.2) and it did compile smoothly.
   • ./configure –without-ssl –disable-log –disable-dynscale
   • Strangely enough, even with the –without-ssl option the openssl library is linked into the pound.exe executable.
   • make
   • Copy the pound.exe and the associated DLLs ( cygssl-0.9.8.dll, cygcrypto-0.9.8.dll, cygrunsrv.exe, cygwin1.dll, cygpcre-0.dll, cygpcreposix-0.dll) to a new directory (e.g. c:\apps\pound)
3. Create a pound.cfg file in the c:\apps\pound directory. Note that the sample config files shown in this site do not work. I am assuming they use commands for an older version of pound that have since been removed
   • A sample config file that works for me is:
   • 
     # Set pound to run like a normal app, so that cygrunsrv can daemonize it
     Daemon 0
     ListenHTTP
     Address 1.2.3.4
     Port 80# Prevent any access to the ZMI from outside
     Service
     URL ".*/manage"
     End# If you have multiple domains, repeat the Service block
     Service
     HeadRequire "Host: .*A.edu.*"
     BackEnd
     Address 127.0.0.1
     Port 8123
     End
     End
     End

   • Note that for this to make sense, the web server (Zope in this case) should be configured to listen only on the localhost ip address (127.0.0.1), and the firewall to block port 8123, otherwise the intent of having only pound exposed to the internet will not be realized.
   • By the way, adding multiple BackEnd directives allows for load balancing, even with prioritization. Really simple and cool!
4. Once you have pound running and have tested it on the command line (pound -f pound.cfg), you want to install it as a service so that it will be automatically started on startup.
   • cygrunsrv –install Pound –path C:\Apps\Pound\pound.exe –args “-f
     C:\Apps\Pound\pound.cfg” –stdout C:\Apps\Pound\pound.log –stderr
     C:\Apps\Pound\pound.log
5. I haven’t configured it yet, but I will be adding additional URL filters to reverse proxy to the IIS server.