Embedded System Definition and Examples
Complexity in embedded processors for hardware and software can add density with the software developers and for general purpose application use.
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Planes, trains, and automobiles: a PCB design tool that can help your boards go places.
When it comes to PCB design it can be easy to lose the forest for the trees. It can be more difficult to find a concise definition for an “embedded system” than to get advice on how to isolate mixed signals in one. So let’s fix that shall we? We are surrounded by embedded systems and interact with them on a daily basis even if we don’t realize it. They’re in our phones, cars, toasters, and maybe even our silverware.
These boards are typically small, rugged, and do specific jobs rather than provide general computing functions. Limiting the scope of what the computer can do allows it to be smaller and more efficient. A smaller form factor does come with some design challenges, particularly when trying to avoid electromagnetic interference (EMI) in your board. Embedded PCBs can be used in things like cars to control a braking system, provide WiFi to passengers on board, or play movies. The sky really is the limit when it comes to embedded systems, as they’re often used in aerospace applications where weight and reliability are absolutely critical.
If it ain’t broke don’t fix it, right? So if normal computers work so well for us in our daily lives, why bother tinkering around with a microcontroller and a custom PCB? The problem with using something like a personal computer to run something like an alarm clock is that a PC is too large, has the excessive processing power, and is far too expensive. In order to get someone up in the morning, you only need a simple LCD screen, a small speaker, a clock IC, a microcontroller, and a board to attach everything to. Using only the necessary electronics allows an alarm clock to be small and inexpensive. A good embedded system does exactly what it needs to, and not much more.
Aiming for the most efficient solution does limit embedded systems in significant ways. Instead of a 64 bit CPU, most of these boards use a 32, 16, or even 8 bit microcontroller. This limits how quickly they can process data or control other elements of the circuit. In addition to reduced brain power embedded systems often have higher durability requirements than traditional computers. A PCB mounted in the body of a car will experience physical shocks and a wide range of temperatures. You might think that these kinds of constraints make it all too much trouble, but the size, weight, reliability, and cost advantages outweigh the extra headache.
How to Successfully Begin a Design
Every engineer knows that experience can sometimes outweigh pure intelligence. That’s why it’s important to start your design with a company that knows what they’re doing. Altium Designer has been used to design both simple and complex embedded PCBs for years. We can give you advice on how to program your microcontroller, design your system, and test it before sending it out.
- The microprocessor is the brains and base of your embedded system, so knowing how to properly use one is absolutely critical. Make sure you learn the basics before starting your design.
- The idea of designing a new PCB can be a daunting one, but Altium Designer helps simplify development. If you don’t believe us just see how it helped a group of college students speed through the design process.
- Before you start making production runs of your board it’s important to test it in a variety of ways. Take a look at our short test list to make sure you have the most common items checked off.
A better question is what don’t embedded systems do? With the growth of the Internet of Things (IoT) the amount and variety of embedded PCBs are exploding. It’s easy to find a specific purpose for a board, the challenge comes in designing for that function. Some common problems that you’ll have to address in your PCBs are electromagnetic interference (EMI), grounding, and high speed design.
Real-time embedded systems are capable of adding whatever necessary computing power to programmable components that you need. Devices with embedded computers or embedded processors enable a vast variety of available programming language or hardware components for use. A circuit board with sensors and actuators, signal processing, and responsible for device drivers will surely utilize embedded systems.
Embedded Design Challenges
EMI, more commonly known as crosstalk, is the underlying problem that causes issues with both grounding and high speed design. When electrical currents travel through a wire or metal in general, they radiate EMI. If you’re designing a wireless antenna this is a good thing, but if you’re not careful you might end up sending signals that interfere with the rest of your circuit. Noise can be conducted as well as radiated to other parts of your board. If you design your grounding planes improperly you can disrupt sensitive signals on your PCB.
PCBs with high speed signals or communication protocols are notoriously difficult to design. High frequency transmission generates a significant amount of EMI that is likely to obstruct signals. Fortunately Altium Designer has features that can help you with each of these design challenges.
- One great strategy for minimizing crosstalk in your circuits is to route certain signals in differential pairs. This is easier said than done, except when you use Altium Designer. Our software lets you define differential design rules and also helps you when it’s time to route differential traces.
- Ground planes can be a pain to arrange, which is why we’ve laid out a few tips and tricks for you in our blogs. Learn how you can take care of mixed signal boards and define ground planes.
- Creating a high frequency board is a real challenge, especially when you don’t start addressing issues right at the beginning. That’s why Altium Designer helps you define rules that help to make high speed boards a breeze.
An example of what multi-board design software can accomplish for you
These lightweight, durable, and sometimes flexible PCBs have found their true home in the aerospace industry. Electronics in air and spacecraft must be as light as possible and fit into tiny spaces. They also have to endure extreme temperatures, are subject to significant thermal shock, and will be rattled around more than your average board. The minimal nature of embedded systems means they can be designed to meet all these criteria.
PCBs at the Cutting Edge
When building boards for the aerospace industry it’s important that even the electrical designers know something about a board’s mechanical requirements and properties. Space and weight are at a premium on airplanes, which means you need to know exactly how much your board will weight, and if it will fit into its allocated space. You will also need to consider how vibration will affect your PCB during takeoff, landing, and general operation. Even the material your board is made out of will play a big part in the amount of thermal or mechanical stress it can take.
Chances are you may also run into rigid-flex boards in the aerospace arena. These are printed circuit board that is built on semi-flexible substrates that allow electronics to be mounted in even smaller places. These kinds of PCBs may also need to be able to bend to a certain radius repeatedly. Designing a rigid flex board is not for the faint of heart, and even the brave will need Altium Designer.
- It can be a pain to wait for someone else to make a 3D model of your board, which is why Altium Designer does it for you. Now you can quickly iterate your designs and see if they fit without having to slow down the process to pass models back and forth.
- Our software won’t pick your substrate material for you, which is why we’ve written a few blogs about which ones to choose. Our expertise in the entire design process is invaluable when it comes to aerospace PCBs.
- Rigid-flex boards are notoriously difficult to construct. We’ve tried to simplify the process as much as possible and can even generate a folded model of your PCB so you can see how everything fits together.
The world around us is becoming more electrified each and every day. Computers are already tiny and engineers are designing them into any object they can get their hands on, so why not join in the fun? Embedded systems are limited scope computers that are primarily built to do one task. This functional efficiency allows them to be inexpensively mass produced in tiny form factors. Limited space and demanding applications lead to many design problems including both radiated and conducted EMI. Even more difficult issues appear when designing for the aerospace industry where weight, size, mechanical properties, and even flexibility become considerably more important. These boards may seem difficult to make, but Altium Designer takes most of the pain out of the process. With a huge knowledge base, design features like differential pair and high frequency routing rules, 3D modeling, and rigid-flex modeling Altium Designer is the clear choice for embedded system design.