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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Upgrading to Sharp 128×128 Pixel Memory Display


In “Low Power LCD: Adafruit Breakout Board with Sharp Memory Display” I used a 96×96 Sharp Display (LS013B4DN04) with the Adafruit breakout board, but because that one seems to be EOL (End Of Life), I searched for a replacement. I have found the 128×128 pixel version (Sharp LS013B7DH03), and best of all, it is pin compatible :-). With a small tweak of the driver, it works :-):

Sharp Memory Display 128x128

Sharp Memory Display 128×128

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Using Python, Gatttool and Bluetooth Low Energy with Hexiwear


Now I can use the data on the Hexiwear over BLE with the gatttool (see “Tutorial: Hexiwear Bluetooth Low Energy Packet Sniffing with Wireshark” and “Tutorial: BLE Pairing the Raspberry Pi 3 Model B with Hexiwear“). This article is taking things a step further and uses a Python script on Linux to access the sensor data on the BLE device:

Accessing Hexiwear Sensor Data with Python

Accessing Hexiwear Sensor Data with Python

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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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Tutorial: BLE Pairing the Raspberry Pi 3 Model B with Hexiwear


The Hexiwear (see “Hexiwear: Teardown of the Hackable ‘Do-Anything’ Device“) is a small and portable sensor node with built-in BLE (Bluetooth Low Energy) transceiver. In a research project we try to use multiple Hexiwear in a classroom environment and to collect sensor data on a Raspberry Pi. The Raspberry Pi 3 Model B running Linux has an on-board BLE transceiver too, so why not binding them (wirelessly) together?

Raspberry Pi 3 connected with Hexiwear over BLE

Raspberry Pi 3 connected with Hexiwear over BLE

Well, things seemed easy at the beginning, and as always, there are many things to learn on a journey like this…

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Low Power LCD: Adafruit Breakout Board with Sharp Memory Display


Many projects benefit from a small display as a user interface. For very low power applications this is usually a no-go as the display needs too much energy. I have used e-paper displays from Kent: while these e-paper displays do not need any power to keep the image, changing the display content is not for free, plus is very slow (around 1 second needed to update the display). So I was looking for something low power and fast for a long time, until Christian (thanks!) pointed me to a display from Sharp: both very low power and fast:

Font Test with Sharp Memory Display

Font Test with Sharp Memory Display

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McuOnEclipse Components: 12-Dec-2016 Release


Time is passing by so fast, and the year end is approache fast! I’m pleased to announce that a new release of the McuOnEclipse components is available in SourceForge:

  • Percepio Trace V3.1 for FreeRTOS which includes both Segger RTT continuous streaming and snapshot tracing in a single API
  • Generation of sources and drivers so they can be used without Processor Expert using McuLibConfig, removal of dependency to NXP Kinetis SDK: components use a generic API approach to have them working with other SDKs.
  • New contributed ExceptionsHandler component
  • Callback Setter and Getter in USB CDC stack for simpler option handling
  • GenericTimeDate with flexible RTC support and added Unix Timestamp functions
  • LongKey events in Key component
  • FreeRTOS with optimized task selection on Cortex-M4/M7
  • Many smaller bug fixes and enhancements
SourceForge

SourceForge

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Making-Of Sea Shell Sand Clock


The year is coming to an end, the Holiday season is approaching. In case you are looking for a nice present: I have completed my version of a sand clock: a clock writing the time into sand:

Sandclock

Sandclock

If you are interested to build your own version, I have documented the different steps with tips and tricks…

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McuOnEclipse Components: 30-Oct-2016 Release


A new McuOnEclipse components release was long overdue, so I’m pleased to announce that a new drop is available with the following major changes:

  • Segger SystemView library with kernel time reporting
  • GenericTimeDate supports different hardware RTC devices
  • Utility with little endian packet handling functions
  • Shell Standard I/O handlers for USB CDC, Segger RTT and Bluetooth
  • FreeRTOS and stack size reporting
  • printf() support in Shell component
  • Various small bug fixes and improvements
SourceForge

SourceForge

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Tutorial: Building FreeRTOS Applications for ARM Cortex-M4 on i.MX7 with Eclipse


Command line tools to build applications are great. But productivity goes up if I can use the standard Eclipse environment with GNU tools. This tutorial is about how to use standard and free GNU and Eclipse tools to build my FreeRTOS application for the ARM Cortex-M4 on i.MX7 🙂 :

Eclipse used to build FreeRTOS applications for M4 on i.MX7

Eclipse used to build FreeRTOS applications for M4 on i.MX7

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Tutorial: Updating Embedded Linux on Toradex i.MX7 Colibri Module using SD Card


My Toradex i.MX7Dual module comes with a preflashed Linux distribution (see “Tutorial: First Steps with NXP i.MX7 and Toradex Colibri Board“). As with any other things, Linux gets updated from time to time, and Toradex publishes new firmware. In this article I’m documenting how I can update Linux in the external FLASH on that module.

NXP i.MX7Dual Module

NXP i.MX7Dual Module

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Tutorial: Running FreeRTOS on NXP i.MX7Dual Cortex-M4F


In my previous article (see “Tutorial: First Steps with NXP i.MX7 and Toradex Colibri Board“) I have booted the i.MX7 on a Toradex CPU module. In this post I’m showing how to run a FreeRTOS application on that board.

UART-A and UART-B Connections

UART-A and UART-B Connections

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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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Tutorial: RFID Tags with the NXP NFC Controller PN7120 and Eclipse


Playing with RFID and NFC is definitely fun :-), and they are everywhere! For a research project I’m exploring different RFID tags and solutions. I several types around for a long time, but never found the time to actually work on it, so last nightI thought I give it a try, and I have it working with GNU ARM and Eclipse, powered by the NXP FRDM-K64F board 🙂

NXP NFC PN7120S

NXP NFC PN7120S with a FRDM-K64F Board

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Tutorial: Blinky with Kinetis SDK V1.3 and Processor Expert


This tutorial goes through the steps how to create a blinking LED application, using Kinetis SDK and Processor Expert, using the TWR-KL43Z48M board from Freescale (now NXP):

twr-kl43z48m

twr-kl43z48m

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Enclosure for the Remote Robot Controller with LCD Display


The first enclosure for the INTRO robot remote controller board (see “INTRO Robot Remote – First Production PCB“) is ready, and it is looking good:

Enclosure for the Remote Controller Board

Enclosure for the Remote Controller Board

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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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