The Steps for Embedded Systems Design

Key Takeaways

• Learn what embedded systems design is. 

• Understand the embedded systems design cycle.

• Identify top challenges in embedded system design.

I’ve heard a particular internet marketer say, “Every master was once a disaster.” This motivated me to pick up origami—the Japanese craft of artful paper folding. And, what a disaster I was. I even struggled to grasp the basics, such as making even, crisp folds. 

Regretfully, I gave up before I had any chance of being a master. I guess I’m just lacking talent and follow-through in crafts. Thankfully, I have made great strides with embedded systems design. It was passion, non-stop learning, and many failures that fueled my mastery of embedded systems design. Let’s take a look at what this technology is, what its uses are, and learn from my mistakes, which means if this is new to you, don’t give up so easily. 

What Is Embedded Systems Design?

Microcontrollers are the core of an embedded system.

Embedded systems refer to electronic products that are based on microcontrollers. They possess computational logic, memories, communications, I/O peripherals and are usually used for a specific function. A washing machine is an embedded system. The same goes for your smartphone, security access system, vending machine, and possibly any ‘intelligent’ appliances. 

Embedded systems design is the process where hardware and firmware designers come together to build embedded systems from scratch. This involves PCB design, where the necessary components are connected to build functional circuits. To bring the electronics to life, the firmware is coded and then programmed into the microcontroller. 

Embedded Systems Design Cycle

Creating schematic diagrams is one of the stages of embedded systems design.

Embedded systems design can be overwhelming if you’re tackling it without a good plan. However, a systematic approach helps break the design cycle into manageable stages, which allows proper planning, execution, and collaboration.

Analysis of Requirements

The first crucial stage in embedded systems design is to gather and analyze the product requirements and turn them into specifications. You’ll need to list out every single requirement and clarify them with your manager or client. 

It is not all about the number of I/Os and the logic diagram. Probing into the usage and operating conditions helps in determining the right specifications for the embedded system. One that works in an indoor environment is very different from an embedded system that needs to reliably function in harsh conditions. 

Schematic 

Once the requirements are translated into specifications, the hardware designer can start building the schematic. In this stage, the design team will need to choose the right microcontroller and other components for the circuit.

The microcontroller is the heart of an embedded system. Considerations like processing speed, memories, peripherals, power consumption, and cost need to be given much thought before making final decisions. 

PCB

With the schematic completed, the next task is to design the PCB for the embedded system. PCB design is a delicate process and the designer needs to apply best practices for functionality, manufacturability, and reliability. 

PCB design gets complicated when you’re working on a high-speed microcontroller and/or mixed-signal circuits. High-speed designs give rise to problems like EMI, and mixed-signal designs require proper ground separation and noise-coupling mitigation measures.

Prototype

After the PCB layout passes the DRC test and is free from error, you’ll need to get the prototypes done. With many suppliers offering low-volume prototyping, this isn’t an issue.

Firmware Development

Hardware is only part of the equation of an embedded system design. Firmware designers need to bring the hardware to life with the coding to make it all work. The process can be sped up by making use of existing driver libraries and sample code offered by the manufacturer. 

Still, developing firmware is a time-consuming process, and a single misplaced line of code can result in hours of debugging. 

Testing & Acceptance

Before an embedded system design is approved for manufacturing or deployment, it has to pass stringent tests. Not only does it need to pass functionality test cases, but the circuit must also be tested for reliability, particularly when operating near its limits. 

Challenges in Embedded Systems Design

PCB design is arguably the most crucial part of embedded systems design.

It’s obvious that every stage of embedded systems design is important. However, if there’s one area that I found particularly crucial to a successful outcome, it is the PCB design. 

You can fix bugs and other code issues with a firmware revision, but when PCBs are manufactured, any mistakes will result in substantially costly remedies and reworks. Therefore, you must carefully design and test when designing the PCB for an embedded system. 

Issues like EMI can be prevented or minimized by implementing strict design rules. Thermal heat points, an issue that can reduce the lifespan of components, can be addressed by running thermal analysis over the PCB layout.

Today’s embedded designs often go beyond the scope of just electronics. You’ll also need to ensure that the design fits perfectly into the enclosure. This calls for an ECAD/MCAD function where designers of both disciplines can collaborate seamlessly in the same workspace and in real-time. 

It isn’t exaggerating to say that a major part of embedded design success is attributed to using the right PCB design and analysis software. You’ll find OrCAD PCB designer’s features perfectly optimized for designing embedded systems and getting them right the first time. 

If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts. You can also visit our YouTube channel for videos about PCB design and layout as well as check out what’s new with our suite of design and analysis tools.