Tutorial: Secure TLS Communication with MQTT using mbedTLS on top of lwip

One of the most important aspects of the ‘IoT’ world is having a secure communication. Running MQTT on lwip (see “MQTT with lwip and NXP FRDM-K64F Board“) is no exception. Despite of the popularity of MQTT and lwip, I have not been able to find an example using a secure TLS connection over raw/native lwip TCP :-(. Could it be that such an example exists, and I have not found it? Or that someone implemented it, but has not published it? Only what I have found on the internet are many others asking for the same kind of thing “running MQTT on lwip with TLS”, but there was no answer? So I have to answer my question, which seems to be a good thing anyway: I can learn new things the hard way :-).

Blockdiagram MQTT Application with TLS using lwip

Block diagram MQTT Application with TLS using lwip

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MCUXpresso IDE: Installing Processor Expert into Eclipse Neon

In “MCUXpresso IDE: Importing Kinetis Design Studio Projects” I explained how Kinetis Design Studio projects can be imported and used inside the MCUXpresso IDE. Processor Expert projects can be used, but no new components added, modified or new Processor Expert projects created. To fully use Processor Expert, two plugins need to installed, and this is what this article is about.

Processor Expert in MCUXpresso IDE

Processor Expert in MCUXpresso IDE

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MCUXpresso IDE: S-Record, Intel Hex and Binary Files

This is another article about the NXP MCUXpresso IDE (see “MCUXPresso IDE: Unified Eclipse IDE for NXPs ARM Cortex-M Microcontrollers“), this time it is about Post-build steps. Post-build steps are custom actions which can be executed after the build (or link phase), and are typically used to generate S-Record, Binary or Intel Hex files (see “S-Record, Intel Hex and Binary Files“).

Post Build Steps Details

Post Build Steps Details

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MCUXpresso IDE: Unified Eclipse IDE for NXPs ARM Cortex-M Microcontrollers

There are many mergers going on in the industry, and one of the largest one was in 2016 the integration of Freescale Semiconductor with NXP Semiconductors, with both providing Eclipse based IDE’s to their customer base. Consequently, the company merger triggered a merger of the IDE’s, and last week NXP has released the result: the MCUXpresso IDE.

MCUXpresso IDE

MCUXpresso IDE

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Percepio FreeRTOS Tracealyzer Plugin for Eclipse

Good news for everyone using Eclipse, FreeRTOS and Percepio Tracealyzer: Percepio has released an Eclipse plugin which makes snapshot tracing very easy and convenient using the a GNU gdb debugger in Eclipse like Kinetis Design Studio:

Eclipse with Percepio Tracealizer

Eclipse with Percepio Tracealyzer

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Tips for Making Copy of Eclipse CDT Projects Easier

Instead creating a new project from scratch, often it is simpler to copy an existing Eclipse CDT project, then change it and go on.  To copy-past the a project in Eclipse:

  1. Select the project in the Project Explorer View (CTRL-C on Windows)

    Copy of a project

    Copy of a project

  2. Then paste it in the Project Explorer View (CTRL-V on Windows), and I can specify the new name:

    Paste of Project

    Paste of Project

However, to make that process simpler, a few things have to be done right in the ‘source’ project first.

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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: 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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ARM Cortex-M Interrupts and FreeRTOS: Part 3

This is the third part about ARM Cortex-M and how the interrupts are used. In Part 1 I discussed the Cortex-M interrupt system and in Part 2 I showed nested interrupt examples. This part is about FreeRTOS and how it uses the Cortex-M interrupt system.

NXP KV58F ARM Cortex-M7

NXP KV58F ARM Cortex-M7

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ARM Cortex-M, Interrupts and FreeRTOS: Part 1

The ARM Cortex-M microcontroller are insanely popular. And it features a flexible and powerful nested vectored interrupt controller (NVIC). But for many, including myself, the Cortex-M interrupt system can be counter-intuitive, complex, inconsistent and confusing, leading to many bugs and lots of frustration :-(.

NXP KV58F ARM Cortex-M7

ARM Cortex-M7: NXP KV58

Understanding the NVIC and the ARM Cortex-M interrupt system is essential for every embedded application, but even for if using an realtime operating system: if you mess up with interrupts, very bad things will happen….

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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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First steps: ARM Cortex-M7 and FreeRTOS on NXP TWR-KV58F220M

For a university research project I need a fast microcontroller with lots of RAM and FLASH memory. I have ordered a TWR-KV58F220M board from NXP which arrived yesterday. The special thing is that it has on of these new ARM Cortex-M7F on it:

TWR-KV58F220M Box

TWR-KV58F220M Box

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