Embedded Glossary

6LoWPAN stands for "IPv6 over Low-Power Wireless Personal Area Networks" and denotes a set of mechanisms that enable IPv6 packet transmission over energy- and resource-constrained wireless networks based on IEEE 802.15.4. These include IPv6 header compression and fragmentation of packets that exceed the size of a single IEEE 802.15.4 frame. This allows constrained devices to gain IPv6 connectivity and integrate into IP-based networks.

Android is a partially open-source Operating System based on a Linux kernel and originally developed for mobile devices. It increasingly supports graphical operator terminals and industrial displays. Its runtime environment and framework execute applications. Hardware-specific versions adapt processors, peripherals and drivers. Documented APIs and development tools support dependable implementation.

ARM is a RISC processor architecture used in embedded systems. It combines low power consumption with high performance per watt. ARM licenses core designs to semiconductor manufacturers for microcontrollers and systems-on-chip. Cortex families address control tasks and operating-system-based applications. ARM offers a scalable basis for embedded design.

Atom is a family of microprocessors from Intel based on the x86 architecture that combines low power consumption with a compact form factor. Most variants are implemented as a system-on-chip (SoC), integrating the processing core, graphics unit and interface logic on a single chip. This makes the range suitable for embedded devices with graphical user interfaces, industrial PCs and networked controllers requiring processing power with low heat dissipation. Unlike a microcontroller, an Atom processor has sufficient performance to run a full operating system and standard software. Its x86 compatibility allows familiar desktop software to be used directly.

Barebox is an open-source Bootloader for embedded systems. It initializes hardware after power-up, then loads and starts the OS. Its POSIX structure offers file access, device model, and command line. The Device Tree separates hardware descriptions from code. Barebox supports multistage booting, firmware updates, and redundant configurations. It supports maintenance.

A base board is a printed circuit board in an embedded device that combines key components, power supply and connectors. It often accommodates a System on Module (SoM) and routes its signals to individual assemblies. The term is frequently used interchangeably with carrier board, although a base board also contains its own electronics.

Broadcom is a semiconductor manufacturer whose components are used in numerous embedded systems. Its portfolio includes system-on-chip solutions (SoCs) and components for wired and wireless communication, networking, and other applications. In embedded environments, Broadcom is known for its SoCs, which integrate functions such as processor cores, graphics units, and peripheral interfaces on a single chip. The BCM2711 and BCM2712 SoCs used in various Raspberry Pi single-board computers are well-known examples.

Buildroot is an open-source tool that creates a complete, tailored Embedded Linux system from source code. Its configuration determines the components included in the target system. Buildroot generates a toolchain, the kernel, and a lean root file system. It provides a fixed image without run-time package management. This keeps the software image compact and clearly defined.

C is a procedural, imperative programming language created for system-level software development and still regarded as a standard for hardware-oriented tasks. Its source code is translated into machine code tailored to the processor architecture. A lean language core, high execution speed, and precise control of memory and system behaviour are characteristic. At the same time, it requires deliberate management of memory and access, which remains the developer’s responsibility. Its standardisation and closeness to the machine make C portable across many architectures, making it suitable for drivers, system-level libraries, and logic close to the microcontroller. On resource-constrained platforms, C remains a widely used foundation.

C# is an object-oriented programming language from Microsoft that operates at a higher abstraction level through intermediate language and is closely associated with .NET. In embedded systems, it supports application development and device-related software for configuration, diagnostics, service, and technical user interfaces. It enables productive development, clear architectures, and maintainable solutions.

C++ is a compiled programming language that extends the system-level foundation of C with object-oriented and generic concepts. It combines hardware-oriented control with tools for structuring, encapsulating and reusing code. This keeps the generated machine code efficient while allowing larger software systems to be structured more clearly. In embedded development, the language is suited to complex applications, system-level components and communication logic where runtime behaviour and architectural quality must align. Standards from C++17 onwards provide additional capabilities without sacrificing access to memory and peripherals close to the microcontroller. Unlike purely application-oriented languages, C++ remains close to the hardware and can be compiled into efficient, resource-conscious machine code.

Configuration software enables embedded devices to be parameterised and adapted to their operating environment. Typical settings include IP address, device name, language and operating functions. It can run directly on the device through a local GUI or integrated web server, or on a PC. It supports flexible device deployment.

Debayering describes the process that generates a colour image from the raw data of a sensor with a Bayer Pattern filter. Each sensor cell provides only a single numerical value for red, green, or blue. During debayering, the colour components are combined and weighted from the values of neighbouring cells so that, in the end, a pixel receives a complete RGB value. As an early step of image processing , the process influences sharpness, colour fidelity, and the occurrence of artefacts at edges. Computational effort and latency depend on the selected algorithm and on whether processing takes place in the ISP, on the GPU, or on the CPU. The process supports a complete RGB representation for every pixel.

Debian is an open-source Linux distribution that combines a kernel with an extensive, tested collection of software packages through configuration to form a complete operating system. It is characterised by solid package and patch management, supported by releases maintained over the long term. Debian is available for several CPU architectures, not only for x86 or x64. In the embedded environment, Debian is suitable for more powerful devices such as industrial computers or operator terminals that have enough memory and processing power for a full-fledged system. Compared with a leanly built Embedded Linux, Debian comes with a ready-made package ecosystem that reduces the effort required for setup and facilitates later updates. At the same time, the system is larger and can be tailored less finely to scarce resources. Debian provides a ready-made package ecosystem for suitable embedded devices.

A Device Tree describes peripheral hardware in an embedded system independently of the Linux kernel. It specifies processors, memory, buses, pins and connected peripherals. At startup, the kernel evaluates data and loads the appropriate Kernel Driver. Hardware variants can be adapted without modifying kernel code. A maintained Device Tree supports transparent hardware integration.

Embedded Linux combines a Linux kernel with a tailored root file system for embedded devices. It contains only target-specific components, conserving resources. Tools such as Buildroot or OpenEmbedded generate the configuration from source code. Its open codebase and maintained versions suit long-lived devices subject to the Cyber Resilience Act (CRA).

Embedded redesign updates an existing device by adapting hardware, software or both to new requirements. Obsolete hardware often forces replacement components. The change affects processor selection, board layout, drivers and firmware. A target-platform change may require porting so established functions remain reliable. It preserves proven functionality on the new basis.

Firmware is hardware-oriented software stored persistently in an embedded device that directly controls its electronics. It forms the layer between physical hardware and the application, coordinating the processor, memory, and connected peripherals. It often runs directly on a microcontroller. It provides a dependable basis for device operation.

GStreamer is an open-source framework for handling audio and video streams. It combines components for capture, conversion, encoding and playback. Written in C, it can be configured or extended as needed. GStreamer provides a flexible basis for multimedia processing in embedded systems.

GUI stands for Graphical User Interface and refers to a system’s graphical control interface. It visualises information and receives user input. In embedded devices, it forms the visible software layer of an HMI and mediates between users and devices. Clear responses, clarity and low resource requirements support reliable device operation.

i.MX 8 is a processor family from NXP for high-performance embedded systems. Depending on the variant, it combines ARM Cortex-A cores for applications with Cortex-M cores for time-critical control tasks. It supports Embedded Linux and Operating Systems for connecting complex peripherals. Thus, i.MX 8 combines application logic and deterministic responses on one platform.

An i.MX processor belongs to a range of application processors from NXP that is based on the ARM architecture and tailored specifically to embedded devices. Its defining feature is the bundling of processing cores, graphics and video units and numerous interfaces on a single chip. The range extends from economical devices for simple controllers to powerful variants for operator terminals, industrial computers and image processing, on which Embedded Linux usually runs. The device often sits on a system on module, which provides the processor and memory as an interchangeable unit. The assured availability horizon of several years shapes its suitability for products with a long life cycle. With its broad performance range and a mature ecosystem, the i.MX processor dependably covers almost every class of embedded device.

An interrupt briefly interrupts normal program execution to handle asynchronous events. When it is triggered by a GPIO, the microcontroller saves its current state and executes the associated interrupt service routine. After processing, program execution resumes at its original position. Interrupts enable reliable responses to external signals.

Java is an object-oriented language whose source code is compiled into platform-independent bytecode. A virtual machine executes this bytecode on the target system and manages memory automatically. In embedded systems, Java supports configuration, diagnostics, and integration with higher-level systems rather than firmware. It enables maintainable supporting applications.

NVIDIA Jetson Orin is a platform for edge AI and robotics. It combines a powerful ARM processor with an NVIDIA GPU and enables AI models to run directly on the device without a permanent cloud connection. The family includes Jetson Orin Nano, Orin NX and AGX Orin, which differ mainly in computing performance, power consumption and memory configuration.

Jitter is variation in recurring events expected at intervals. It is the difference between scheduled and actual timing, such as when an interrupt is handled. Unlike latency, which measures response delay, it describes variation across repeated executions. System load and competing access can cause it. Low jitter improves predictability.

A kernel driver is a hardware-oriented software component within the kernel that enables communication between the operating system and a specific hardware component. Among other tasks, it initializes and configures the relevant component, processes interrupts, and provides the kernel and the system components above it with standardized interfaces for accessing the hardware. Reliable operation is ensured by a targeted kernel driver test. The device tree describes the hardware components available in the system, along with their properties and resources. Based on this information, the kernel can detect the corresponding devices and initialize the intended drivers. In this way, kernel drivers enable standardized integration of connected hardware in an embedded system.

Latency is the time between a triggering event and the corresponding system response. In embedded devices, it covers each delay from signal arrival through processing to a measurable or visible response. For periodic events, jitter is the timing deviation from the arithmetic mean. Both metrics support real-time requirements. Low latency enables prompt, predictable system responses.

Linux is an open-source, freely available operating system kernel originally developed for Unix-like systems. Its portability enables use across many processor architectures. Embedded Linux adapts Linux to resource-constrained, application-specific devices. An RT Patch supports more predictable response times. Linux enables flexible system configurations for embedded devices.

Logging records events, states, and messages while software is running. Unlike tracing, it focuses on individual events and states rather than the temporal and functional sequence of processing. It supports monitoring, debugging, and fault analysis. Logging provides diagnostic data during operation through serial interfaces or persistent storage.

LoRa (Long Range) is a proprietary radio technology for energy-efficient data transmission over long distances at low data rates. It uses chirp spread spectrum modulation and operates in licence-free frequency bands. LoRa is particularly suited for battery-powered devices.

Low-level programming describes the hardware-oriented development of software. It frequently uses C or assembler and requires detailed knowledge of the target hardware. As part of embedded programming , it enables efficient firmware, drivers or start-up code.

MIPI CSI (Camera Serial Interface) transfers image data from an Image Sensor or Camera Module to an embedded processor. CSI-2 uses multiple lanes for high data rates with few conductors. Lane assignment, clocking, and SoC processing make it sensitive to timing and data-format deviations. MIPI CSI enables compact camera connections.

NFC stands for Near Field Communication and describes a wireless technology that enables two devices to exchange data over just a few centimetres. Unlike RFID, it supports bidirectional communication. The short range arises from inductive coupling between two loosely coupled antenna coils and requires deliberate proximity for each connection. NFC enables controlled device interaction.

NVIDIA is a technology company that develops graphics processors, AI accelerators and computing platforms for demanding parallel workloads. The Jetson platform offers compact System on Chip (SoC) devices and computer systems for edge AI and robotics. Jetson Orin combines an ARM-based CPU with an NVIDIA GPU using Ampere architecture.

OP-TEE (Open Portable Trusted Execution Environment) is an open-source trusted execution environment for ARM-based systems that complements a non-secure Linux kernel. It primarily uses Arm TrustZone technology to provide hardware isolation. OP-TEE supports protected execution of security-critical functions.

OpenEmbedded is an open-source build framework that can be used to create tailored Embedded Linux systems from source code and further components. So-called recipes and layers describe how individual software components are fetched, configured, compiled, and assembled into a system image. The separation of description and the actual build process enables reproducible and versionable builds and facilitates the maintenance of complex systems. Together with the tools and metadata of the Yocto Project, OpenEmbedded forms the technical basis for numerous professional Embedded Linux products and distributions. Compared with the more leanly structured Buildroot, OpenEmbedded offers an extensive layer and metadata model that is particularly suitable for complex product lines maintained over the long term. In addition, different package formats and mechanisms for package management can be generated for the target system. OpenEmbedded supports flexible package management for the target system.

An OS image is a system image for an embedded device. It usually contains the kernel, a root file system, and configuration data. Depending on deployment requirements, the bootloader may also be included. Written to non-volatile memory, it provides a reproducible software baseline at each startup. This supports consistent software states.

QML (Qt Modeling Language) is a declarative language for designing graphical user interfaces within the Qt framework. Rather than specifying every step, it describes an interface through individual elements, their arrangement and their behaviour. Animations, states and user input can be expressed concisely and clearly. QML typically connects to C++ for the underlying logic, separating presentation from functionality. In embedded systems, it is particularly suitable for HMIs on more capable devices running Embedded Linux that require a fluid, touch-operated GUI. This separation simplifies maintenance and later extensions.

Qt is a comprehensive framework for cross-platform applications that combines graphical user interfaces with building blocks for networking, data management and concurrent processing. The core language is C++, which provides access to the individual functional areas. The interface itself can additionally be described in the declarative language QML, which allows presentation and application logic to be kept apart. In an embedded context, Qt is particularly suited to more capable devices running Embedded Linux, on which it supports demanding, touch-operated displays together with the underlying logic of a modern HMI. For resource-constrained targets, reduced variants such as Qt Quick Ultralite are available, limiting the scope to the essentials.

The Raspberry Pi is a single-board computer that combines a processor, working memory, and numerous interfaces on a compact printed circuit board. Its central component is a system-on-chip from Broadcom based on the ARM architecture, capable of running a full-featured operating system such as Embedded Linux. A pin header provides digital inputs and outputs as well as serial buses for connecting sensors, displays, and other peripherals. Originally designed for educational purposes, it is now often used as a readily available platform for prototypes and small production runs. For long-lived products, the guaranteed availability period and suitability for the industrial temperature range require careful evaluation. Its broad ecosystem of accessories and active community significantly lowers the barrier to entry for embedded systems development.

Real-time describes an embedded system’s ability to react to events within a precisely defined period. RTOS, RTLinux and VxWorks support this behavior where exceeding the maximum response time can cause damage. Latency is the response time, while jitter is its deviation from the mean. Real-time behavior supports dependable embedded operation.

Reconnect restores a previously interrupted network or device connection. A detected connection loss or a Timeout triggers a new connection attempt. Limited retries with increasing delays reduce unnecessary load on the device and network. Controlled reconnect handling maintains availability during temporary disruptions.

A regression is an unintended deterioration or a recurring fault in software that was already working after a change. It can result from modifications to firmware, drivers or configurations and impair previously fault-free device functions. Clear modularization and regression tests identify such side effects early.

An RT Patch extends the Linux kernel with PREEMPT_RT mechanisms for more predictable timing. It makes many kernel sections preemptible and shifts most Interrupt handling to prioritised threads. This reduces Latency and jitter. RT Patches enable real-time responses on Embedded Linux systems.

RTOS stands for Real-Time Operating System and is an operating system that plans tasks according to priorities and complies with binding time limits. It enables predictable reactions to events and limits latency as well as jitter. RTOS is the basis for critical control systems with fixed timing behaviour.

Secure Boot allows an embedded device to execute only verified, unaltered software at startup. The bootloader validates each stage's digital signature and stops the boot process if verification fails. This establishes a chain of trust through the operating system, preventing manipulated firmware from running. Secure Boot preserves device integrity.

Security by Design means incorporating security requirements early into the architecture, hardware, and software of an embedded device. Threat model, access control, and secure update mechanisms are established before implementation. This reduces the attack surface and supports Embedded Security throughout the lifecycle. Security by Design strengthens system resilience.

A single board computer (SBC) is a complete computer in which all essential components are housed on a single printed circuit board. These include, among others, the processor, working memory, graphics, interfaces, and power supply. A well-known example is the Raspberry Pi. An SBC usually runs an operating system, for example Linux. Owing to its compact design, comparatively low cost, and versatile interfaces, an SBC is particularly suitable for the rapid and cost-effective implementation of projects.

Sitara is a Texas Instruments family of ARM-based processors and microcontrollers for embedded industrial and automation applications. Members such as AM335x integrate a Cortex-A8 core, graphics unit, and interfaces. With suitable software and hardware, they can implement industrial protocols. Sitara supports integrated industrial control designs.

A touchscreen (touch display) combines a display with touch sensing. As an HMI, it lets users directly select displayed elements. Capacitive or resistive technology is selected according to operating conditions. Depending on its design, it withstands dust and moisture. A suitable touchscreen supports intuitive device operation.

Ubuntu is an open-source Linux distribution that combines a kernel with a broad selection of tested software packages into a complete operating system. It is based on Debian, but places particular emphasis on ease of use, regular releases, and long-term supported LTS versions. In embedded environments, Ubuntu is primarily used as a development and test environment on capable computers, and less often as a lean target system such as Embedded Linux.

USB Power Delivery (USB-PD) is a standard for negotiating voltage, current, and power-flow direction over a USB connection. The source and sink agree on a suitable power profile before power flows. The standard is independent of manufacturers and devices. USB-PD enables flexible, reliable power supply for embedded devices.

V4L2 (Video4Linux2) is the programming interface of the Linux kernel that applications use to access cameras and video inputs. It configures image format, resolution, exposure, capture, and image-data transfer. A Kernel Driver exposes source capabilities and registers. Buffering maintains a stable data stream at high frame rates. V4L2 supports reliable camera integration in embedded systems.

White-box testing examines software with full knowledge of its internal structure. Unlike Black-box testing, test design uses source code, program structure and implementation details. It enables targeted execution of paths, branches and conditions, while measuring code coverage. For hardware-oriented Firmware, it reliably reveals internal logic faults.

Windows CE was a compact, modular Operating System from Microsoft for resource-constrained devices with fixed timing requirements. As an early foundation of Windows Embedded, it supported operator terminals, handhelds and industrial controllers. Microsoft has ended support; legacy devices receive no security updates. Embedded Linux offers a maintainable migration path for such systems.

Windows Embedded refers to specially tailored versions of the Microsoft operating system for embedded devices such as operator terminals, point-of-sale systems, or industrial control systems. Unlike the classic desktop version, it can be reduced modularly to the required components and thus adapted to limited memory and defined functions. Historically, the series ranges from Windows CE via Windows Embedded Compact to variants based on Windows for stationary devices. Compared with a leanly built Embedded Linux, it offers a closed ecosystem with versions maintained over the long term.

x86 refers to a 16/32-bit processor architecture that was initially developed by Intel. The name is based on the first 16-bit CPU, _8086_, in this series from 1978. By design, x86 is assigned to the CISC architecture; originally with 16-bit-wide registers and a data bus as well as a 20-bit address bus and therefore a maximum of 1 MB of addressable memory. The first instruction set is still supported today. In the 1980s and 1990s, this architecture dominated the desktop segment and was manufactured under licence and further developed by other manufacturers (AMD). To this day, it represents a de facto standard. In the embedded field, it is used when compatibility with the desktop field, including the operating system used, and high processing performance are the priority. This is associated with high power consumption (65–105 W for the AMD Ryzen™ Embedded 7000 Series) and high thermal load. With CPUs not manufactured specifically for the embedded field, all interfaces must be connected as external hardware. x86 remains a de facto standard for embedded applications requiring desktop compatibility and high processing performance.

Xilinx is a supplier of programmable logic devices whose FPGAs and SoC families have been run under AMD's roof since its acquisition in 2022. An FPGA can be freely configured after manufacture and processes signal paths in parallel in hardware, rather than working through them step by step on a processor. Well known is the Zynq range, which combines programmable logic and an ARM processing core on a single chip. One example is the Zynq-7000 family with a core from the Cortex-A9 series. On the processing core, an Embedded Linux often runs, while time-critical data streams arise directly in the FPGA. This makes the architecture well suited to fast sensor connection and image processing. Where software and signal processing have to mesh closely, Xilinx brings its strengths of programmable hardware and an integrated processor fully to bear.

Yocto is an open-source project for building Embedded Linux platforms. It combines tools, metadata, and build processes to reproducibly assemble a kernel, root file system, and software packages for target hardware. It uses OpenEmbedded and the BitBake build engine as its foundation. Yocto produces tailored system images for embedded devices.

Zynq is an AMD/Xilinx SoC family that combines ARM processor cores with programmable FPGA logic on a single chip. The processor runs Embedded Linux, while the logic handles parallel, time-critical signal processing. It supports cameras, industrial controllers, and high-speed interfaces.