When Is an FPGA Worth it and When is it NOT – when developing an Industrial Embedded System – Part 2
Simulation environments for FPGAs are generally pretty solid, but you eventually have to move into hardware, where your visibility into what’s going on decreases significantly
In part 1 of this article, we introduced some well-suited applications for FPGAs, and highlighted some strengths and weaknesses of FPGAs. Now we transition over to some cautionary elements of utilizing FPGAs.
Some Things to be Mindful Of
Traditional development environments that tend to utilize text-based languages such as VHDL and Verilog are NOT for the casual user. The languages and the tool chains have a steep learning curve and the tool chains can be expensive.
Debugging tools –
The disadvantage of a run-of-the-mill sequential processor is that only one operation is executing at any point in time. The advantage of a sequential processor is that only one operation is executing at any point in time. When it comes to debugging, this sequencing makes life easier than debugging an FPGA. Simulation environments for FPGAs are generally pretty solid, but you eventually have to move into hardware, where your visibility into what’s going on decreases significantly. You can view outputs of course, and you can create test points, but you have to be able to probe all of those points, so you’ll need a logic analyzer, which can get very pricey. You may be able to get away with embedding test resources into your device (e.g. Xilinx has the Integrated Logic Analyzer), but this will utilize FPGA logic and memory resources, and is often challenging to see enough breadth or depth about what’s going on inside your FPGA. However, generally these tools are better for augmenting a true logic analyzer, as opposed to replacing them outright.
Cyber security –
A lot of FPGAs are embedding Ethernet cores, common processor cores, and some are even running an OS, making it so FPGA-based (sometimes referred to as SoC (system on a chip)) solutions look like another computer on the network. This opens up their vulnerability to more traditional attack methods. Take the time to understand your risks and mitigate them. Obscurity is generally NOT a solid security approach (check out The Great Debate: Security by Obscurity). Here are two articles to get you thinking:
- How to build an FPGA-based I&C
- Microsemi Steps Up Its Cyber Security Leadership in FPGAs: SmartFusion2 SoC FPGAs and IGLOO2 FPGAs Enhanced with Physically Unclonable Function Technology
Safety –
If you’re considering an FPGA-based system for a safety-related function, you need to understand the risks that you’re incurring. Here are a few articles to get you thinking:
- Safe FPGA Design Practices for Instrumentation and Control in Nuclear Plants
- SRAM-Based FPGA Systems for Safety-Critical Applications: A Survey on Design Standards and Proposed Methodologies
- Xilinx Reduces Risk and Increases Efficiency for IEC61508 and ISO26262 Certified Safety Applications
Where You Might Head From Here:
Hopefully these thoughts have given you some things to chew on. If you decide it might make sense to proceed with an FPGA-based embedded system and don’t have the time or manpower to create your own solution, check out VERDI. If you’re interested in other industrial embedded system info, check out our resources page.