Zephyr: Thoughts and First Steps on the ARM Cortex-M4F with gcc, gdb and Eclipse

The concept of Linux (Open Source, broad developer base and broad usage) is a success story. While there is a lot of diversity (and freedom) in the Linux world, Linux is Linux and again Linux :-). And the world has (mostly) standardized on Linux and its variants on the high embedded system side.

On the other side, the ‘middle and lower end’ Embedded world is fragmented and in many aspects proprietary. So it was no surprise to me when the Linux Foundation announced the ‘Zephyr’ project back in February 2016:

“The Linux Foundation Announces Project to Build Real-Time Operating System for Internet of Things Devices. Open source Zephyr™ Project aims to deliver an RTOS; opens call for developers to help advance project for the smallest footprint IoT devices.

Ζεφυρος (Zephyros) is the Greek good of spring and the west wind. Obviously this inspired the logo for the Zephyr project:

Zephyr logo
Zephyr logo (Source: https://www.zephyrproject.org/)
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Building the NXP BLE Stack with Open Source GNU and Eclipse Tools

One of the biggest road blocks (beside of closed source) using the BLE (Bluetooth Low Energy) stack from NXP is that it requires expensive tools to compile and build the stack. The good news is that I have now the NXP BLE stack for the Mikroelektronika Hexiwear ported to Eclipse and GNU gcc build tools for ARM 🙂

NXP BLE Stack in Eclipse

NXP BLE Stack in Eclipse

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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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Accessing GNU Linker Script Symbols from C/C++

With the GNU compiler and linker I can place variables into custom sections (see “Defining Variables at Absolute Addresses with gcc“). This article is about how to get the section start and end address so I can for example access that range in my code. Or in general ways: how to use symbols defined in the linker script accessible in the C source code.

Using Linker Script Symbols in Source Code

Using Linker Script Symbols in Source Code

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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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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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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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