Mutex vs. Semaphores – Part 2: The Mutex & Mutual Exclusion Problems
Mutexes tackle many semaphore pitfalls by enforcing ownership and pairing lock and unlock operations, making mutual exclusion safer in RTOS code. This post explains how ownership enables recursion, priority inheritance and death detection, and why mutexes do not automatically solve circular deadlock or non-cooperative access. Read on for practical protocols such as Priority Inheritance and Priority Ceiling and a brief note on monitors.
Off the shelf availability of Custom IoT Gateway
Choosing the right gateway can make or break an IoT deployment, yet industrial gateways are often expensive and generic. This post walks through practical criteria for off-the-shelf and custom gateways, covering edge computing trade-offs, mainframe versus embedded Linux, SoC and ADC choices, interfacing and debugging needs, and when to design your own hardware for real-time or protocol demands.
A brief overview of flight control software
Open source flight control software can feel like a maze of forks, retirements, and overlapping projects. In this post, the author builds a chart and comparison table to map how drone flight controller software evolved over time, using git commit history and repository data. It is a handy starting point if you want a quick overview of the current landscape before diving deeper.
Mutex vs. Semaphore - Part 1
Most forum answers get the semaphore versus mutex debate wrong. This post traces semaphores back to Dijkstra and Scholten, explains the difference between binary and counting semaphores, and highlights runtime hazards such as accidental release, recursive and task-death deadlocks, priority inversion, and misuse as signals. Read if you want to avoid common concurrency pitfalls in RTOS code.
Embedded Programming Video Course Teaches RTOS
From basic foreground/background loops to priority-inheritance protocols, this free video course walks you through building and improving an RTOS step by step. Lessons cover manual context switching, round-robin and preemptive priority schedulers, efficient thread blocking, and synchronization primitives. The series finishes with a practical port to a professional RTOS in the QP/C ecosystem, showing semaphores, mutexes, and ways to prevent priority inversion.
The Hardest Bug I Never Solved
A single overlooked sentence in the STM32 datasheet turned intermittent startup resets into a major time-leach. Senior engineers chased DMA buffers and overflows for hours until Unni discovered the ISR vector table had been relocated to RAM with only 256 byte alignment while the MCU required 512 bytes. The misalignment caused interrupts to jump to the reset handler, and fixing the alignment stopped the reboot loop for good.
Android for Embedded Devices - 5 Reasons why Android is used in Embedded Devices
Android may seem like a phone OS, but it now solves real embedded product problems. This post outlines five practical reasons engineers pick Android for devices with displays, from built-in touch and GUI frameworks to simplified camera and wireless APIs. It also covers vendor BSP and driver support, a large developer pool, and how Android speeds prototyping by reusing phones or tablets as HMIs or processors.
Introduction to Deep Insight Analysis for RTOS Based Applications
Debugging can consume over 40% of a development cycle, and Jacob Beningo argues RTOS projects need more than breakpoints and assertions. He presents deep insight analysis as a trio of techniques—RTOS-aware debugging, run-time analysis, and profiling with coverage—that expose what the system is actually doing. These methods help engineers cut guesswork and speed verification of complex embedded applications.
How to Give Persistent Names To USB-Serial Devices on Ubuntu 14.04
When your dock reshuffles ttyUSB assignments, Tayyar shows how to bind USB-serial devices to persistent names on Ubuntu 14.04. The post walks through using dmesg and udevadm to locate unique attributes like KERNELS and ATTRS{serial}, creating /etc/udev/rules.d entries with NAME and SYMLINK, and applying rules with udevadm trigger. It includes common pitfalls and quick fixes to get minicom talking to the right port.
Vala applications on Embedded Linux: maybe a clever choice [part 1]
If you need a high-level language for constrained embedded Linux devices, Vala is worth a look. It compiles to C and relies mainly on GLib, giving you native performance and minimal runtime dependencies. With reference counting instead of a garbage collector, modern language features, and a small storage footprint, Vala can outperform Python, Java, or Qt on low-RAM, low-storage boards. This first part focuses on dependencies, ABI compatibility, runtime characteristics, and a real-world example.
Introduction to Deep Insight Analysis for RTOS Based Applications
Debugging can consume over 40% of a development cycle, and Jacob Beningo argues RTOS projects need more than breakpoints and assertions. He presents deep insight analysis as a trio of techniques—RTOS-aware debugging, run-time analysis, and profiling with coverage—that expose what the system is actually doing. These methods help engineers cut guesswork and speed verification of complex embedded applications.
Embedded Programming Video Course Shows How OOP Works Under the Hood
Want to see how OOP actually maps to machine level code? This free video course walks through encapsulation, inheritance, and polymorphism with hands-on comparisons between C and C++. You will inspect C implementations, compiler-generated code, and debug traces, and learn how encapsulation relates to RTOS concurrency. The polymorphism lesson reverses the usual order to expose runtime costs and previews implementing polymorphism in C.
How to Give Persistent Names To USB-Serial Devices on Ubuntu 14.04
When your dock reshuffles ttyUSB assignments, Tayyar shows how to bind USB-serial devices to persistent names on Ubuntu 14.04. The post walks through using dmesg and udevadm to locate unique attributes like KERNELS and ATTRS{serial}, creating /etc/udev/rules.d entries with NAME and SYMLINK, and applying rules with udevadm trigger. It includes common pitfalls and quick fixes to get minicom talking to the right port.
Peripheral Interaction Without a Linux Device Driver Using Spidev
Kernel-space drivers are not always necessary; many SPI peripherals can be handled from userspace using spidev. This post shows how to expose an SPI device through the device tree and kernel, wire a Bosch BMP388 to a Toradex Apalis iMX8 Ixora board, and implement a C userspace app that uses ioctl to read the chip ID. Practical tips on SPI settings and logic-analyzer validation are included.
Who needs source code?
Many developers feel that the supplying source code is essential for licensed software components. There are other perspectives, including the possibility of it being an actual disadvantage. Even the definition of source code has some vagueness.
Using XML to describe embedded devices (and speak to them)
Make embedded devices tell you what they can do. Martin Strubel shows how to use XML and XSLT with the DClib/netpp framework to describe hardware, map registers into abstract properties, and auto-generate compact C, documentation, and VHDL. The netpp property protocol then lets you probe, query, and control those properties over TCP, UDP, or other transports, simplifying test benches and multi-device families.
The Hardest Bug I Never Solved
A single overlooked sentence in the STM32 datasheet turned intermittent startup resets into a major time-leach. Senior engineers chased DMA buffers and overflows for hours until Unni discovered the ISR vector table had been relocated to RAM with only 256 byte alignment while the MCU required 512 bytes. The misalignment caused interrupts to jump to the reset handler, and fixing the alignment stopped the reboot loop for good.
Linux Kernel Development - Part 1: Hello Kernel!
Skip userland and run code inside the kernel with a tiny "Hello Kernel" module that prints messages on load and unload. This introduction walks through required headers, the init and exit hooks, MODULE_* metadata, a kernel-friendly Makefile, and the basic workflow to build, insmod, rmmod and inspect messages with dmesg. It’s a hands-on first step into Linux kernel module development.
How to install Ubuntu 12.04 Precise, Xubuntu-desktop and Open JDK-7 on Beagleboard Rev. C2
Want to run Java GUI apps on a BeagleBoard Rev C2? This hands-on post walks through installing Ubuntu 12.04, adding the Xubuntu desktop, and getting OpenJDK-7 running, including SD flashing, u-boot and network setup, display and audio tweaks, and a fix for XFCE login ownership problems. Follow the exact commands and small workarounds the author used to get a monitor, sound, and Java VM working on the board.
Using a board with NuttX RTOS as an RS-485 / Modbus Slave Device
This practical walk-through shows how to turn a NuttX-equipped board into an RS-485 Modbus RTU slave using a cheap MAX485 transceiver and an STM32F4Discovery board. It explains why a simple UART plus a GPIO for DE/RE is enough, why the RP2040 needs special handling, and gives step-by-step configuration in NuttX, wiring for the transceiver, and a quick test using FreeModbus and mbpoll.
ANCS and HID: Controlling Your iPhone From Zephyr
In this blog post, we see how certain BLE services can be used to control an iPhone from a Nordic nRF52840 using The Zephyr Project. Specifically, we see how to control certain multimedia functionality using the HID service. Finally, we learn how to use the ANCS client library provided by Nordic in The Zephyr Project to accept or decline an incoming call.
Hidden Gems from the Embedded Online Conference Archives - Part 1
Discussion of a "hidden gem" from the Embedded Online Conference archives!
Vala applications on Embedded Linux: maybe a clever choice [part 1]
If you need a high-level language for constrained embedded Linux devices, Vala is worth a look. It compiles to C and relies mainly on GLib, giving you native performance and minimal runtime dependencies. With reference counting instead of a garbage collector, modern language features, and a small storage footprint, Vala can outperform Python, Java, or Qt on low-RAM, low-storage boards. This first part focuses on dependencies, ABI compatibility, runtime characteristics, and a real-world example.
Basler pylon on Raspberry Pi with Yocto
Basler's pylon can be packaged into a minimal Raspberry Pi Yocto image in a few clear steps. This walkthrough shows how to clone poky with meta-openembedded, meta-raspberrypi and Basler's meta-basler-tools, tweak conf/local.conf to add OpenCV and accept the Basler EULA, build rpi-test-image and generate an SDK for cross-compilation. It finishes by cross-compiling a pylon_example binary, copying it to the Pi and testing with a Basler acA2440-20gm.
Can an RTOS be really real-time?
Real-Time Operating Systems are meant for real-time applications. But with conventional shared-state concurrency and blocking, can you honestly know the worst-case execution time of an RTOS thread?
Motion Sensor with Raspberry Pi and MPU6050 - Part 1
This blog will help you build your own, low cost 3-axis motion sensor using Raspberry Pi and Invensense MPU6050.
OS influence on power consumption
Power consumption of an embedded system may be influenced in software in general, but selection of an operating system can be key.
How to use analog input (ADC) on NuttX RTOS
Hands-on walkthrough showing how to read analog voltages on a Raspberry Pi Pico running NuttX RTOS. The post explains RP2040 ADC basics, which GPIO channels and the internal temperature sensor are exposed, and how rp2040_adc_setup creates /dev/adc0. It also shows the menuconfig options, build and UF2 flash steps, a simple potentiometer test, and a note about RP2040 ADC spike artifacts.
Getting Started With Zephyr: Using GDB To Fix a Driver Bug
In this blog post, I show how to use GDB to debug an issue encountered with a TSL2591 light sensor driver in Zephyr. The fix was submitted and successfully incorporated into The Zephyr Project.
Using (Apache) NuttX USERLED Subsystem
Controlling an LED with raw GPIO works, but NuttX's USERLED subsystem makes it cleaner and portable. This post walks through enabling the LED driver in menuconfig, mapping the RaspberryPi Pico LED in the board files, and using the /dev/userleds device with printf to set up to 32 LEDs with a single write. It finishes with a hands-on challenge to expand the setup to eight LEDs on a breadboard.
