Why You Should Use an FPGA in Embedded Systems Design

Overview of FPGAs in Embedded Systems

FPGAs provide many advantages in embedded systems that are not seen in popular components like MCUs or MPUs. These components have often been used for application development or to prototype logic implementation on silicon prior to custom chip design. Today, they are playing a greater role in production hardware targeting some important advanced applications. They also provide powerful compute solutions when other components (SoCs, ASICs, application accelerators) are unavailable or do not exist.

Some of the major reasons designers consider FPGAs as the main component in their systems include:

• High compute density with lower power consumption
• Reconfigurable hardware
• High customization and parallelization
• Hardware-level security
• Vendor IP for customization

Semiconductor vendors have done an excellent job of providing and licensing IP for FPGAs. Through available IP and custom application development, it is possible to create a very powerful processor that is specific to one application area. Other processor options do not provide this level of flexibility.

FPGA vs. Other Processor Options

The table below provides a comparison between FPGAs, GPUs, and standard MCU/MPU options.From this table, the FPGA has some distinct advantages in terms of its computing power and reconfigurability, but there can be a tradeoff in terms of development effort and flexibility once placed into operation.

The specialization available in FPGAs is highly desirable in applications like military embedded computing, edge computing systems in industries like banking and finance, telecom, aerospace, and any other area where IP protection is critical. More advanced systems that must dedicate power to intensive computing tasks, including things like on-device AI and blockchain, can greatly benefit from the specialization available in FPGAs.

Getting Started With FPGAs in Embedded Systems

If you’re sold on the benefits of FPGAs as an application-specific compute element in your system, then you’ll need to integrate the component into your system. FPGAs can be included in embedded systems in multiple form factors and architectures.

• Everything on a single board:?This is the standard approach to developing a new product with an FPGA. If you’ve already demonstrated a prototype and tested your application, using a custom board gives you much more control over system architecture. You could even design the board to require a smaller FPGA.
• Start with a dev kit:?One path to prototyping is to use an dev kit and design a custom base board that connects to the development product. The base board can provide connections to peripherals, power, memory, and other components. Once the prototype is proven, you can move onto another system form factor to get into production.
• Start with an SOM:?3rd party SoMs are available, or you can design a custom SoM. You’ll then need to design a base board that matches the pinout and provides connections to other components not found on the SoM. It’s also common to use a custom interposer board to interface two different embedded products.
• Design the FPGA on an expansion card:?If you have an existing system with an expansion card slot over PCIe or high-speed serial interface, you can place the FPGA on the expansion card to expand the capabilities of the system with application-dedicated compute with high density.

There is no objectively "best" form factor or architecture involving implementation of an FPGA. These components can be implemented as the sole processor in an embedded system, alongside another processor such as a GPU, as an accelerator in a traditional computer or embedded system,or as a configurable component on an expansion card. There are many options for FPGA implementation, and the right option depends on your particular application.

The last point to note is that PCB for embedded systems with FPGAs need to be built with best practices for high-speed PCBs.These systems always require specific design points be implemented at the stackup level, with correct routing techniques, and appropriate layout for the FPGA and its supporting components. The challenges that come with designing and manufacturing PCBs for FPGA-based embedded systems often leads designers to start with a vendor-provided evaluation kit or a 3rd party SOM as their initial prototype.

At PCB HERO, we’ve taken all of these approaches with FPGAs in embedded systems, and we know how to implement the best architecture for your system to meet your operational goals. We’ve designed aggressive form factor IoT products with smaller FPGAs and advanced sensor fusion products with large FPGAs. The FPGA configuration, I/O count, chipset architecture, and many other factors will combine to drive the physical form factor of your product. The right design firm can help you find the right compromise for your system and work with you to get your product to market.