Reprogramming the Mikroelektronika Hexiwear Dockingstation


The Hexiwear docking station would have a nice feature: it has embedded a debug circuit (OpenSDA). That way I would not need an external debug probe to debug the Hexiwear. However, a debug probe is required to reprogram the docking station itself:

Repgrogramming the Mikroelektronika Docking Station

Repgrogramming the Mikroelektronika Docking Station

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Debugging ARM Cortex-M0+ HardFaults


To me, one of the most frustrating things working with ARM Cortex-M cores are the hard fault exceptions. I have lost several hours this week debugging and tracking an instance of a hard fault on an ARM Cortex-M0+ device.

Next assembly step will cause a hard fault

Next assembly step will cause a hard fault

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Tutorial: Hexiwear Bluetooth Low Energy Packet Sniffing with Wireshark


For a university reasearch project I try to pair the Raspberry Pi 3 with a Mikroelektronika Hexiwear using BLE (Bluetooth Low Energy). Most of things worked after a lot of trial and error, but at a certain point I was stuck trying to write to send data from the Raspy to the BLE device.The Hexiwear BLE protocol description is very thin, so I ended up using a BLE sniffer to reverse engineer the protocol with Wireshark.

Sniffing BLE Packets between Raspy and Hexiwear

Hardware setup between Raspy and Hexiwear

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Disabling EzPort on NXP Kinetis to Solve Power-On Issues


I’m using the NXP FRDM-K64F board in several projects: it is reasonably prices, has USB, Ethernet, micro SD card socket and connectors for Bluetooth classic and Nordic Semiconductor nRF24L01+ 2.4 GHz transceiver:

NXP FRDM-K64F Board

NXP FRDM-K64F Board

But one issue I have faced several times is that the board works fine while debugging and connected and powered by a host machine, but does not startup sometimes if powered by a battery or started without a debugger attached. I have found that the EzPort on the microcontroller is causing startup issues.

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Failure with Solder Points and Mechanical Pressure


The good thing with failure is: it is an opportunity to learn :-).

So here is a case: For a STEM roadshow (see “MINTomat: World’s Most Complicated Bubble Gum Automata?“), we have produced in a rush an autonomous robot with a shiny printed 3D cover:

LED effect in blue

Prototyp with LED Effects

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Tutorial: Getting ETM Instruction Trace with NXP Kinetis ARM Cortex-M4F


It seems to me that not many developers use hardware trace? ARM indicates that maybe only <5% of developers are using trace. Too bad! Why are all the ARM Cortex microcontroller vendors putting a powerful hardware (and complicated!) trace engine into their devices, if only few developers are using it? Seems like a waste of silicon and an unnecessary price adder? Well, hardware trace can be a life saver: Because only with hardware trace the most complicated bugs and problems can be solved. And maybe because only the best are using it ;-).

In this article I proudly present my research how to get instruction trace out of the ARM Cortex-M4 microcontroller on a NXP TWR-K64F120M board with a Segger J-Trace for ARM:

J-TRACE tracing NXP TWR-K64F Board

J-TRACE tracing NXP TWR-K64F Board

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Tutorial: Using Single Wire Output SWO with ARM Cortex-M and Eclipse


As a standard procedure, I add some console functionality to my embedded applications. That way I have a command line interface and can inspect and influence the target system. One interesting hardware feature of ARM Cortex-M is Single Wire Output (SWO): it allows to send out data (e.g. strings) over up to 32 different stimulus ports, over a single wire.

swo-pin-on-arm-debug-header

swo-pin-on-arm-debug-header

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FreeRTOS Kernel Awareness with Ozone


In my first post about Segger Ozone (see “First Steps with Ozone and the Segger J-Link Trace Pro“) I missed the fact that it includes support for kernels like FreeRTOS. So here is how to show the FreeRTOS (or any other RTOS) threads with Ozone:

freertos-threads-in-ozone

freertos-threads-in-ozone

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First Steps with Ozone and the Segger J-Link Trace Pro


From time to time I face some problems which are really hard to find. Mostly these kind of bugs are very timing sensitive and depend on interrupt execution order. Maybe a dangling pointer is overwriting memory, code is running wild, or some functions are not reentrant as they should be. For these kind of bugs, good tools are worth their weight in gold. The Percepio FreeRTOS+Trace and the Segger SystemView have helped me many times to narrow down such kind problems in my applications. Another ultimate tools is hardware trace: Now I have a Segger J-Trace Pro for ARM Cortex-M in my arsenal of bug extinguishing weapons on my desk:
Dear bugs, look what I have on my desk. Your hiding time is over! 🙂

tracing-cortex-m4-with-j-trace

tracing-cortex-m4-with-j-trace

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ARM Cortex-M, Interrupts and FreeRTOS: Part 2


In “ARM Cortex-M, Interrupts and FreeRTOS: Part 1”  I started with the ARM Cortex-M interrupt system. Because the ARM implementation cann be very confusing, I confused myself and had to fix and extend the description in Part 1 :-). Thank for all the feedback and comments!

Originally I wanted to cover FreeRTOS in Part 2. Based on the questions and discussions in Part 1 I thought it might be a good idea to provide visual examples.

NXP KV58F ARM Cortex-M7

NXP KV58F ARM Cortex-M7

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Eclipse and GDB: Process Properties, Arguments and GDB Traces


To me this was new, and thanks to Liviu I know now how to inspect the command line passed to the GDB server (see “Semihosting (again!) with NXP Kinetis SDK V2.0“) 🙂

Process Properties

Process Properties

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Semihosting (again!) with NXP Kinetis SDK V2.0


I kind of hoped that after “Why I don’t like printf()” and all my other articles about printf and semihosting, that topic would be 200% handled and I won’t have to deal with any more. Well, I was wrong and underestimated how the Kinetis SDK is interfering with semihosting. And I underestimated how many of my readers are still using semihosting (even as there are other and better alternatives), so I keep getting questions and requests for help. That’s ok, and I hope I can help :-).

So here is yet again another post about how to turn on semihosting with Eclipse, GNU ARM Embedded and the Kinetis SDK v2.0. This time with the FRDM-K64F board:

FRDM-K64F Board with lwIP running

FRDM-K64F Board

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Bricking and Recovering OpenSDA Boards in Windows 8 and 10


Getting a board from a distributor like Farnell/Element14/Mouser (add your own distributor) means that chances are high that the default firmware on it is written years from now because the inventory has not been updated, or because boards are still produced with that original firmware (because of testing?). So what happens if I use board with a firmware developed pre-Windows 8/10 area?

Freshly Unboxed NXP FRDM-KL25Z Board

Freshly Unboxed NXP FRDM-KL25Z Board

It might work, but chances are high that the bootloader and firmware is not ready for the ‘modern age’, and as a result the board might be bricked. If you still have a Windows 7 machine around (I do!), you are lucky. If not, then you need to read this article….

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McuOnEclipse Components: 31-July-2016 Release


Time for a new major update of the McuOnEclipse components, with the fillowing main features and changes:

  • FatFS component updated to R0.12 with patch 3 and exFAT support
  • Extended support for Cortex-M7
  • Extended support for Kinetis SDK V2.0
  • USB component support for Kinetis SDK V1.3
  • Improved FreeRTOS for NXP FreeRTOS TAD plugin
  • Added C++ wrappers to multiple components
  • Many smaller fixes and improvements

    SourceForge

    SourceForge

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impulse: Segger SystemView in Eclipse


I’m using the Segger SystemView in many of my applications to get insights of the running application. A reader of my blog pointed me to the company ‘toem’ (http://toem.de/) based in Germany which offers powerful data viewer (‘impulse’) for Eclipse. I have tried this out, and it is really an amazing piece of technology with lots of potential. It allows me to view Segger SystemView data 🙂

Segger SystemView Data in Eclipse

Segger SystemView Data in Eclipse

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Hexiwear: Teardown of the Hackable ‘Do-Anything’ Device


Smartwatches are around for a while now. To me it is still questionable how useful the ‘big’ ones for iOS and Android are. But there are definitely the crowd funded smartwatch projects which caught my attention. Maybe it is about the ‘do-anything’ with connectivity?  One of these gadgets is Hexiwear: a hackable open source device

Hexiwear Device

Hexiwear Device

While it *could* be a kind of smartwatch, the value of this thing is more that it includes a plethora of sensors with two microcontroller, and I can use Eclipse with GNU tools to build my firmware :-).

Alert: Hackster.io is giving away 100 Hexiwears, but you need to hurry up (submission until July 15th 2016)!

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Board Bring-Up Tips, GDB Logs and Traces in Eclipse


Sometimes things don’t go well, especially with bringing up a new board design. I always sweat blood that first minute when I try to connect with the debugger to a new design: Will it work? After the optical inspection, performing electrical tests (no shortcuts? voltage levels ok?) the inflection point is when I’m connecting the first time with the debugger to the new board: either it will properly connect and program the device (hurrah!) or it will fail and potentially difficult hours of investigations have to follow.

First PCB under Debug

First PCB under Debug

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How to Recover the OpenSDA V2.x Bootloader


More and more of my students are using Microsoft Windows 10 machines, and my computer has been upgraded to Windows 10 a couple of week ago too. From my work and experience, a new operating system causes always some challenges, and Windows 10 is no difference. And no, this is not about Microsoft vs. Apple vs. Linux, this post is about addressing a potential and painful problem which I have observed with Windows 10 machines, and to my understanding it could happen with any other operating system too. The problem is that somehow on several student machines the bootloader and OpenSDA application on their FRDM boards did not work any more.

FRDM-K64F (top) programming the OpenSDA Bootloader (bottom)

FRDM-K64F (top) programming the OpenSDA Bootloader (bottom)

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