Category Archives: Debugging

Failed to Debug with GDB: Breakpoints or Expressions on non-existing Locations

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Sometimes, there are ugly bugs in tools, and without knowing about them, it is likely to spend hours and hours, and of course to be frustrated. Knowing about these issues does not remove the issue, but at least helps to cut time to deal with it. And here is one which was nagging on me for a while with the GNU GDB debugger in Eclipse…..

💡 I have used the Q4 2014 GNU ARM Embedded (launchpad) toolsuite/gdb (4.9-2014-q4-major), and I have found that with that gdb version the issue described is fixed. If you are using Kinetis Design Studio, see “Switching ARM GNU Tool Chain and Libraries in Kinetis Design Studio” how to upgrade the tool chain.

I was happily debugging my project, making some changes, and suddenly I cannot debug it any more. What happens is that I can download the binary with GDB, but it immediately terminates and disconnects:

Terminating Gracefully Target Disconnected

Terminating Gracefully Target Disconnected

After digging and doing some trial and errors, I have found what is causing this.

Initializing.
Target has been RESET and is active.
Disconnected from "127.0.0.1" via 127.0.0.1
Terminating Gracefully...
Target Disconnected.

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Unlocking and Erasing FLASH with Segger J-Link

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When using a bootloader (see “Serial Bootloader for the Freedom Board with Processor Expert“), then I usually protect the bootloader FLASH areas, so it does not get accidentally erased by the application ;-). When programming my boards with the P&E Multilink, then the P&E firmware will automatically unlock and erase the chip. That’s not the same if working with the Segger J-Link, as it but requires extra steps.

Protected FLASH Pages with Processor Expert

Protected FLASH Pages with Processor Expert

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Emulating Eclipse ‘Run’ with ‘Debug’ Configuration

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Student: “Professor, my application does not work!”
Professor: “What is the problem?”
Student: “I don’t know, but the LED on my board is not blinking.”
Professor: “Can you step through the port initialization sequence and check if the clocks are initialized correctly?”
Student: “I have pressed the ‘Run’ button, I’m not debugging”.
Professor: “Why are you not debugging?”
Student: “I always do a ‘Run’, and I do ‘Debug’ only if needed.”
Professor: “Ahhhhhhrrrrgggg!”

Run and Debug in Eclipse

Run and Debug in Eclipse

Clearly, I’m not immune to the ‘déformation professionelle‘. I very rarely use ‘Run’, because it simply does not offer much value compared to ‘Debug’ during development. If using ‘Run’ and then there is a problem, I have to ‘Debug’ anyway, why not ‘Debug’ from the beginning? It is simply not an efficient way to work for me. Or I’m missing something?

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Comparing CodeWarrior with Kinetis Design Studio

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At FTF 2014, Freescale made the announcement that CodeWarrior won’t support all the new ARM Kinetis devices coming out in the future: they will be supported with the free-of-charge Kinetis Design Studio (KDS) instead. As for myself, this is a big shift from a well established CodeWarrior toolchain to something new. A question which came up recently several times in the forums and in other posts is: how do CodeWarrior and KDS compare with each other?

CW vs KDS

CW vs KDS

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Semihosting with GNU ARM Embedded (LaunchPad) and GNU ARM Eclipse Debug Plugins

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In “Semihosting with Kinetis Design Studio” I used printf() to exchange text and data between the target board and the host using the debug connection. Kinetis Design Studio (KDS) has that semihosting baked into its libraries. What about if using the GNU ARM Embedded (launchpad) tools and libraries (see “Switching ARM GNU Tool Chain and Libraries in Kinetis Design Studio“)? Actually it requires two more steps, but is very easy too.

Semihosting Output

Semihosting Output

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P&E Eclipse Update Site for GNU ARM Eclipse Plugins

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P&E has just released a new version of their Eclipse plugins for the set of GNU ARM Eclipse debug plugins. The GNU ARM Eclipse plugins from Liviu support OpenOCD and Segger J-link, so with this update or extension it adds P&E support to it. With this, I can use the P&E debug devices (P&E Multilink, Tracelink) or as well the Freescale OpenSDA with it.

PnE Debug Interfaces

PnE Debug Interfaces

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Hacking the Teensy V3.1 for SWD Debugging

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I *love* the Freescale Freedom boards, and you probably recognized that with all my projects using them. The Freedom boards are small, inexpensive and can be easily extended with Arduino shields which makes them a great platform for prototyping. But sometimes I just need an ARM microcontroller with some headers, and then the 85mm x 55mm size of the Freedom board is not ideal. That’s nothing new, but I realized that yet again when I did my Adafruit NeoPixel clock: the FRDM board was rather bulky, even if hidden behind that clock. I need something much smaller: the Teensy board!

Size Comparison FRDM vs. Teensy

Size Comparison FRDM vs. Teensy

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Converting S19 Files into Binary Files with GNU objcopy

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Typically I can create with my build the file I usually need (like an S19). See “S-Record Generation with gcc for ARM/Kinetis” how to do this in CodeWarrior, or “Binary Files for the mbed Bootloader with Eclipse and GNU ARM Eclipse Plugins” how this works in Kinetis Design Studio. The basis of all this is the GNU objcopy utility (see “S-Record Manipulation with GNU objcopy and Burner Utility”). So what if I just have an S19 (S-Record) file and need it in a different format, e.g. as .bin (binary) file for the mbed bootloader which only accepts .bin (raw binary) files?

Converting S19 to BIN

Converting S19 to BIN

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Preserving Memory Ranges with Eclipse and P&E GDB Server

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For my boot loaders I need the functionality that I can keep memory ranges from being erased while downloading the rest of the application. P&E provides a GDB server which interfaces with their probes (P&E Universal Multilinks, Tracelinks, …) and as well with the OpenSDA present on many of the Freescale evaluation boards. In CodeWarrior there is an option for ‘Advanced Programming Options’ which allows to preserve memory of the microcontroller FLASH (see “Programming part of flash“). However, that option or button is not present in the Eclipse version of the P&E GDB server (e.g. in Kinetis Design Studio). So how can I preserve some areas of FLASH in Eclipse with GDB?

Preservation of Non-Volatile Memory in CodeWarrior

Preservation of Non-Volatile Memory in CodeWarrior

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