What Is Embedded Systems Programming?

The modern age is centered around technology. Consumers can use so many different devices to make their lives easier. From dishwashers to smartphones, people’s lives are filled with these useful devices.

While most people are familiar with the operating systems that come with computers, laptops, and smartphones, many do not think twice about how other electronics, such as dryers or air fryers, work. Very few will attempt to actually open up their devices to see what makes them tick and learn about the intricate embedded programming underneath.

There is so much to learn about how numerous embedded systems function and work to make consumers’ lives that much simpler. Delving into the complex operating systems of these machines can enlighten many on how their devices perform.

What are Embedded Systems?

To put it simply, an embedded system is a device that is not a computer but is integrated with embedded software to allow it to function appropriately. These embedded devices contain microprocessors and microcontrollers to help them perform a specific function or group of functions.

Equipment such as a microwave, a smart fridge, and the “check engine” system in an automobile are all considered embedded systems. Even the cute Tamagotchis made for children are an example of an embedded system. They all function for the same reason: the specific real-time operating systems designed for the particular device’s embedded hardware.

The Difference Between Embedded Systems Programming and Traditional Operating Systems

Embedded software does not have the same programming that complete operating system-based programming would. The embedded hardware has certain structures and other limitations that developers must consider.

These considerations include the use of microprocessors, microcontrollers, circuitry, and other parts specific to an embedded system’s design. Developers must work with the system hardware specifications to create an embedded programming solution that is able to function properly.

Standard computers and laptops offer various functions and come with a keyboard and screen. Embedded systems look and operate in a completely different way.

An embedded system might not have a screen or keyboard, such as a thermostat. It may or may not be programmable. The embedded software may also be responsible for one singular task or a larger group of tasks, like a car’s embedded control systems.

Embedded systems programming helps tiny computers power the control systems of everyday equipment and hopefully bring the devices one step closer to accessing the world wide web. Some automobiles, security systems, and other devices already have internet capability in their hardware components.

Main Features of Embedded Systems

There are a variety of qualities that embedded systems tend to share. There are many similarities among their hardware configuration and their software designs.

Processor Engine

Every computer must have a processor to function correctly, including those in an embedded system. Developers can choose to use either a microprocessor or a microcontroller.

A basic microprocessor requires separate integrated circuits needed for a device’s memory and any necessary peripherals. A microcontroller, however, has its memory and peripherals included in the chip's construction. Developers can choose which option is best for their needs.

A microprocessor focuses on providing the processing power needed by the device and offers better processing speeds. However, a microprocessor requires more support circuitry to function adequately, and having several different pieces means there is a greater possibility that things could go wrong. Microcontrollers allow the size, power usage, and price of the device to be reduced.

Purposeful Design

Every embedded system is created for a particular purpose. Each one has optimizations that enable it to meet the performance necessities of the function they need to perform. Your device may have an embedded system built for connecting to the internet and another for an alert function.

All embedded systems have features in common while also possessing unique inputs, outputs, power needs, memory requirements, applications, and operating systems dependent on the device. They are all unique and created for one specific task and no other function.

No User Interface

Computers and mobile phones all have a user interface included, which provides users with a way to interact with their devices. The user interface can include speakers, headphones, keyboards, computer mice, and more.

This is a bidirectional system that allows users to receive information and send information back to the computer. Some embedded systems operate with a user interface, but most are built without one. They typically do not have a reason to interact with a user and rely heavily on data from sensors.

For example, the computer that controls the oil monitoring system in an automobile will use sensors to keep an eye on the oil level and output an automated response based on the information provided by the sensor. Drivers cannot interact with this system through a user interface, although they will receive an indication when the embedded system notices a problem.

Embedded systems with no user interface work correctly for a long time without any user input. The embedded software must be thoroughly debugged before being sent out. Developers can employ software development tools, such as a protocol analyzer, to quickly find and fix any bugs that are present.

Real-Time Operating System

Embedded systems tend to utilize RTOS, or real-time operating systems, to ensure that applications within the system can quickly process data. Tenths of a second are used to measure any delays in the systems processing, and the tiniest delay can result in a system failure.

Developers must ensure that the system can always process data within a set period. There are two common designs when creating a real-time operating system, which are event-driven and time-sharing.

An event-driven operating system will switch to a different task only if it is of higher priority than its current task. The operating system manages the functions according to their level of importance.

A time-sharing operating system changes functions regularly using a clock interrupt. The tasks are not assigned a priority level. The embedded software shifts between tasks often to ensure that each one is completed.

Applications Are Built-In

Embedded software development is made with a specific purpose or application in mind. Users will most likely be unable to install external applications onto the device after it is created. Therefore, any applications needed to run the embedded system are built-in.

Embedded systems are considered hardware and software products. The hardware is uniquely designed to meet the particular performance requirements of the applications and embedded software.

Resource Limitations

Software developers have to design the computers for embedded systems around stringent resource limitations. They are often required to be small in size with as few components as possible, which creates a limited amount of resources for the computer.

The embedded engineers have to cram memory into a very small package. Any increase in processing or memory can also increase the cost.

Power Limitations

Embedded systems for portable devices typically run off of battery power. These power limitations will affect the embedded system design choices.

These devices cannot consume too much power when being used. If they do, the user will frequently have to change out batteries or recharge the device. Therefore, an efficient design with low power usage lessens operating costs.

Basic Structure of Embedded Systems

The structure of an embedded system combines a hardware layer and a software layer.

Hardware Layer

The hardware is made up of many different components. Typically, sensors help convert any physical data into an electrical signal. Analog-to-digital, or A-D, converters are also needed to switch analog electrical signals to digital signals.

There are also digital-to-analog, or D-A, converters that will change any digital data received from the processor into analog data. The processors will help process digital signals and store them in the system’s memory.

Actuators analyze actual output to the output stored in the system’s memory. They can also choose the correct one.

Peripherals are things like cameras that may be included within the hardware. Input and output devices are also typically incorporated into the hardware.

Software Layer

The embedded software can be intricate. However, the software is fairly simple and needs very little memory. Firmware is included and designed for the device’s specific hardware.

The operating system of the embedded software is either general-purpose or real-time. The middleware allows connections between the operating system and the applications.

The application software contains most of the programming language for the system’s tasks and interacts with users. All of these software components can be included within the embedded software, or some may be missing depending on the device.

Different Embedded System Types

Embedded systems are separated into categories according to performance and functional requirements and the performance of the microcontrollers.

There are four main groups for the performance and functional requirements of the devices. These are real-time, standalone, network, and mobile embedded systems.

There are three main groups when considering the performance of the system’s microcontrollers. These are small-scale, medium-scale, and large-scale embedded systems.

Real-Time Embedded Systems

A real-time embedded system will provide results and outputs quickly. Priority is designated for the output generation speed in these devices.

Equipment that uses a real-time embedded system is typically used in a mission-critical scenario, like defense or aerospace. These situations require important information as soon as possible. Examples of this type of equipment are missile defense controls, vehicle controls, and aircraft controls.

These devices can be split into hard and soft real-time systems. Soft systems are more tolerant of the timeframe of their output. If information is not provided by a certain deadline, there may be a decrease in performance, but nothing significant will happen. The outputs are still considered valuable information, though, and provide non-mission-critical data analysis, like the temperature.

Hard systems are the exact opposite and have to consistently reach given output deadlines. If they do not, it equals a system or application failure. A hard real-time embedded system not reaching its deadline can produce dangerous results because these systems are used in critical settings.

Standalone Embedded Systems

These devices need no host computer to function and can produce outputs on their own. Examples of standalone systems include digital watches, dishwashers, calculators, and more.

The independence of standalone systems is not the standard for all embedded systems. In fact, many embedded devices only function as part of a bigger system.

For example, the anti-lock brake system, or ABS, in a car is practically useless when taken out of the vehicle. This means it is not a standalone embedded system.

However, a digital camera produces output by itself with some input from the user. There is no need for a more extensive system, so it is considered standalone.

Network Embedded Systems

These systems depend on wired or wireless networks and web server connections to produce an output. Examples of these systems would be security systems and point-of-sale, or POS, systems.

A POS system is connected through several workstations and a server that keeps track of customer transactions, sales, and other important information. It relies on a network of other devices to function.

Mobile Embedded Systems

This category includes small and portable embedded devices. There is some intersection between the mobile systems and standalone systems categories.

It is similar to the concepts of squares and rectangles. All mobile systems are standalone, but not all standalone systems are mobile.

For example, your dryer or fridge is a standalone system. However, neither is necessarily portable, which means they are not mobile embedded devices.

Small, Medium, and Large-Scale Embedded Systems

These categories are based on the performance ability of the microcontrollers in the device. Small-scale embedded systems contain an 8-bit to 16-bit microcontroller.

Medium-scale systems have a 16-bit to 32-bit microcontroller. Large-scale systems, which are the most sophisticated, use 32-bit to 62-bit microcontrollers.

The processing speed is enhanced as the microcontroller bit-count increases.

Uses for Embedded Systems

Defense

Defense operations require high-performance sensors and navigation and communication solutions. These embedded devices are essential to the industry.

Examples of embedded devices in the defense industry are UAVs and surveillance systems, weapons and guidance systems, electronic warfare systems, and command and control systems.

Aerospace and Aviation

These industries also require navigation and communication solutions with high-performance sensors. These devices are responsible for taking off and landing as well as the satellites that are in orbit around Earth.

Examples of embedded systems in these industries are air traffic control systems, flight control systems, navigation systems, flight recorders, collision avoidance systems, and a variety of radar systems.

Consumer, Healthcare, Automotive, and Telecommunication

Embedded devices can be found all over the place in everyday life. They make life easier and aid in certain careers and tasks.

Some examples of embedded devices in these areas are household appliances, communication and entertainment devices, ATMs, security systems, computer systems for cars, MRI scanners, and pacemakers.

Top Programming Languages for Embedded Systems

Embedded systems differ from typical computer programs and, therefore, need a wide variety of tools to program them properly. There are many different program languages that can be used successfully.

Python is a concise and readable programming language that is a popular choice. It is able to streamline the development of the application. This programming language is especially useful with real-time embedded systems.

C and C++ are standardly chosen programming languages for embedded devices. Each programming language provides speed as well as accessibility to system components that are lower level. C# is also part of the family of C programming languages and is object-oriented and structured.

Java is a programming language that is popular with desktop computers. It can create portable applications for a wide range of different software types.

There are lesser-known options too that also produce fantastic results when programming embedded systems, including the Elixir programming language and the Ada programming language.

While Python, C, and C++ are at the top of the list, you can also use several other programming languages to get the job done. Some other options are Assembly, Arduino, Rust, Verilog, and VHDL.

Top Operating Systems for Embedded System Programming

There are plenty of options to choose from when picking out an operating system for your embedded device.

Windows CE is specifically made for industrial controllers and automotive computers. It is becoming obsolete, though, and can be replaced with Windows 10 IoT.

Linux is the standard operating system for smart appliances. ThreadX is another real-time operating system for smart devices.

Integrity is a hard real-time operating system developed by Green Hills, which is used in the military, aerospace, and medical fields. QNX is an RTOS for critical mission systems in automobiles and robotics. VxWorks is an RTOS that works in embedded systems from aerospace and defense to consumer electronics.

Conclusion

Embedded systems can be found all around and are a useful part of everyday life. They come in the form of home appliances, medical equipment, defense technology and more.

Unlike a standard computer, embedded devices are much smaller and can be fit into convenient and portable packages. While their size is often miniscule, their processing power is great.

Many programming languages and operating systems can be used when programming an embedded system. Some are more useful for certain functions. Real-time operating systems are necessary if timing is important.

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