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Tutorial: Understanding and Using FreeRTOS Software Timers

Posted on May 27, 2018 by Erich Styger

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Hardware Timers are essential to most embedded applications: I use them mostly for triggering actions at a given frequency, such as acquiring data from a sensor. With using an RTOS I can do a similar thing using a task: the task will run with a given frequency and I can periodic work in it. However, using a task might be too much overhead doing this. The good news is that there is a much more efficient way to do this in FreeRTOS with Software Timers. And this is what this tutorial is about: how to use Software Timers with FreeRTOS.

FreeRTOS Software Timers

FreeRTOS Software Timers

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Understanding FreeRTOS Task Stack Usage and Kernel Awareness Information

Posted on May 21, 2018 by Erich Styger

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When using the FreeRTOS Task List in the Eclipse based MCUXpresso IDE, it shows the list of tasks with their stack size used. But with the default FreeRTOS settings it is not able to determine the correct stack size and shows a warning icon:

Warning for Stack Usage

Warning for Stack Usage

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Sneak Preview: DIY SMT Pick & Place Machine with OpenPnP

Posted on May 5, 2018 by Erich Styger

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I apologize: I have not been blogging much in the past weeks :-(. One reason is that I’m working on a DIY SMT/SMD Pick&Place machine which keeps me busy most of my spare time :-). I admit that this project is not finished yet, but now is the time I can give a sneak preview: a SMD/SMT pick and place machine:

Pick&Place Machine

Pick&Place Machine

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McuOnEclipse Components: 1-Apr-2018 Release

Posted on April 1, 2018 by Erich Styger

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It’s April Fool’s Day, but be assured this is not a joke ;-): I’m pleased to announce that a new release of the McuOnEclipse components is available in SourceForge. This release includes several smaller bug fixes and components have been upgraded for FreeRTOS V10.0.1.

SourceForge

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Performance and Runtime Analysis with FreeRTOS

Posted on February 25, 2018 by Erich Styger

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One of the great things with the FreeRTOS operating system is that it comes with free performance analysis: It shows me how much time is spent in each task. Best of all: it shows it in a graphical way inside Eclipse too:

FreeRTOS Runtime Information in Eclipse

FreeRTOS Runtime Information in Eclipse

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Faster FreeRTOS Percepio Tracealyzer Streaming with Segger RTT

Posted on February 18, 2018 by Erich Styger

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To solve the real hard problem of Embedded Systems development, I usually need all the data I can get from the target. The Percepio Tracealizer is such a tool which can stream application and FreeRTOS trace from the target over a Segger J-Link connection using the Segger RTT protocol. I’m using that combination a lot.

Streaming trace data that way does not need a dedicated hardware like ETM Trace. Using RTT is usually not much intrusive and affects the performance of the target in the 1-2% range (of course depending on the amount of data).

But what worried me for several weeks is that after moving to FreeRTOS V10.0.0 and the same time updating the Segger libraries, the target performance was heavily affected:

RTT Streamnig affects target performance

RTT streaming affects target performance?

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McuOnEclipse Components: 26-Dec-2017 Release

Posted on December 26, 2017 by Erich Styger

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I’m pleased to announce that a new release of the McuOnEclipse components is available in SourceForge., which is supposed to be the last release for 2017 :-). This release features several smaller bug fixes, the new FreeRTOS V10.0.0 and extended device support.

SourceForge

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New Concept for 2018 Mini Sumo Roboter

Posted on December 17, 2017 by Erich Styger

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Doing Mini Sumo robot competition is really fun, and there is yet another one coming to end the current university semester. For several years we have used our own sumo robot, and this is the one used in the course this year too. But for future and extended events we are exploring a new robot. I proudly present the concept of the next generation sumo robot for the year 2018:

Sumo Robot with Bluetooth module

Sumo Robot with Bluetooth module

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New FreeRTOS V10.0.0: Amazon, Segger SystemView and Percepio Tracealyzer

Posted on December 9, 2017 by Erich Styger

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“Amazon FreeRTOS – IoT operating system for microcontrollers”: The announcement of FreeRTOS V10.0.0 was one of the biggest news last week for me. Not only is there now a Version 10, the bigger news is that FreeRTOS is now part of Amazon. Wow! Now this explains why Richard Barry (the founder behind FreeRTOS) was kind of hiding away for about a year: he joined Amazon as a principal engineer about a year ago. I think we all have to wait and see what it means for FreeRTOS.

Amazon FreeRTOS

Amazon FreeRTOS (Source: Amazon Web Site)

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First tinyK22 Board with NXP K22FN512 ARM Cortex-M4F

Posted on December 8, 2017 by Erich Styger

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The NXP Freedom boards are very popular. Many of them are inexpensive (less than $20), include a debug interface and can be easily extended with extra shields or boards. Especially the FRDM-KL25Z is very popular: I’m getting told because of Processor Expert and tutorials available on web sites like this one ;-).

Unfortunately there are no small or breadboard friendly Kinetis boards available. There is the NXP LPC800-DIP but with no onboard debugger and without Processor Expert support. We have the tinyK20, but projects tend to use more CPU power, FLASH and RAM space than what the tinyK20 board (50 MHz, 128 KByte FLASH, 16 KByte RAM) can provide. So we ended up designing the big brother of the first tinyK20: the tinyK22 with 120 MHz, 512 KByte of FLASH and 128 KByte of RAM.

tinyK22 Overview

tinyK22 Overview

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McuOnEclipse Components: 25-Sept-2017 Release

Posted on September 25, 2017 by Erich Styger

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I’m pleased to announce that a new release of the McuOnEclipse components is available in SourceForge. In this release more ARM Cortex devices/vendors are supported with different SDKs, plus it comes with several FreeRTOS enhancements for debugging highly optimized code.

SourceForge

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Using Multiple Memory Regions with the FreeRTOS Heap

Posted on September 18, 2017 by Erich Styger

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ARM Cortex-M microcontrollers can have multiple memory controllers. This is a good thing as it allows the hardware to do multiple parallel memory read/writes. However this makes the memory map more complicated for the software: it divides the memory into different regions and memory segments. This article is about how to enable FreeRTOS to use multiple memory blocks for a virtual combined memory heap:

FreeRTOS with Segmented Heap Memory

FreeRTOS with Segmented Heap Memory

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Troubleshooting Tips for FreeRTOS Thread Aware Debugging in Eclipse

Posted on July 27, 2017 by Erich Styger

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FreeRTOS seems to get more and more popular, and I think as well because more and more debugger and Eclipse IDE vendors add dedicated debugging support for it.

FreeRTOS Threads in Eclipse

FreeRTOS Threads in Eclipse

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McuOnEclipse Components: 09-July-2017 Release

Posted on July 9, 2017 by Erich Styger

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I’m pleased to announce that a new release of the McuOnEclipse components is available in SourceForge, with the following major changes and updates:

Complete refactoring for 1-Wire stack and DS18B20 temperature sensor components
Added HID Joystick device class to the FSL_USB_Stack
New SDK_Timer component to work with Kinetis SDK
New ST756P LCD driver component
New TSL2561 digitial temperature sensor driver
Added ReadByte() and WriteByte() GenericI2C functions
Added 64bit mapping functions to Utility
added configUSE_NEWLIB_REENTRANT and newlib reentrancy support to FreeRTOS
Pull resistor support for SDK_BitIO
Many smaller bug fixes and enhancements

SourceForge

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Using FreeRTOS with newlib and newlib-nano

Posted on July 2, 2017 by Erich Styger

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For reliable applications, I avoid using functions of the standard libraries. They are banned for most safety related applications anyway. I do not use or avoid malloc(), printf() and all the other variants, for many reasons including the ones listed in “Why I don’t like printf()“. Instead, I’m using smaller variants (see “XFormat“). Or I’m using only the thread-safe FreeRTOS heap memory allocation which exist for many good reasons.

Things get problematic if malloc() still is pulled in, either because it is used by a middleware (e.g. TCP/IP stack) or if using C++. Dave Nadler posted a detailed article (http://www.nadler.com/embedded/newlibAndFreeRTOS.html) about how to use newlib and newlib-nano with FreeRTOS.

FreeRTOS Newlib Memory Allocation Scheme

FreeRTOS Newlib Memory Allocation Scheme

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DIY USB HID Joystick Device and Game Controller

Posted on June 4, 2017 by Erich Styger

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For many projects it would be cool to build a custom USB Joystick device, either as custom game controller for Windows or any USB host which can be used with a USB Joystick. Instead buying one, why not build my version? All what I need is a USB capable board, some kind of input (potentiometer, push buttons) and some software, and I have my USB Joystick:

DIY USB HID Joystick Device

DIY USB HID Joystick Device

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McuOnEclipse Components: 06-May-2017 Release

Posted on May 6, 2017 by Erich Styger

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I’m pleased to announce that a new release of the McuOnEclipse components is available in SourceForge, with the following changes and updates:

SEGGER SystemView updated to V2.42
More components to work with MCUXpresso SDK: GenericSWSPI, FXO8500 and SimpleEvents
SSD1351 display driver supports 128×128 pixel resolution and Adafruit 1.5″ breakout module
Extended FreeRTOS debug helper settings
GenericI2C: added ReadWordAddress8() and ReadWordAddress8() functions
RingBuffer with new Getn() and Update() functions
Utility with map(), constrain(), random() and randomSetSeed()
XFormat: new xsnprintf(), contributed by Engin Lee
OneWire protocol component with Maxim DS18B20 temperature sensor
Many smaller bug fixes and enhancements

SourceForge

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MCUXpresso IDE: Installing Processor Expert into Eclipse Neon

Posted on April 9, 2017 by Erich Styger

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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: Unified Eclipse IDE for NXPs ARM Cortex-M Microcontrollers

Posted on March 28, 2017 by Erich Styger

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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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Tutorial: Using Eclipse with NXP MCUXpresso SDK v2 and Processor Expert

Posted on March 25, 2017 by Erich Styger

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To me, software and tools are by far more important than the microcontroller. Because the silicon is a ‘one time kind of thing’, where the software has to be maintained and working over a longer time. And at least my software usually needs to be ported to a new device, so portability and available software and tools are critical to me.

The combination of MCUXpresso SDK (formerly Kinetis SDK) and Processor Expert is unfortunately not supported by NXP. But I have found a way to get them work together in a nice way, and this article is about making that combination possible :-).

SDKv2 Project with Processor Expert

SDKv2 Project with Processor Expert which is supposed not to work together

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