It’s not about the processor anymore

It’s not about the processor anymore

Flexible FPGA-based designs focus on IP

BY MARCELLE DOUGLAS
Altium
Frenchs Forest, Australia
http://www.altium.com

It’s natural to think of the processor as the heart of an embedded system. With CPU speed and peripherals determining the overall capabilities that a new product can achieve, it’s easy to understand why this preoccupation drives most projects. This mindset, however, isn’t without its drawbacks and may soon become outdated, given current trends.

Having the processor placed in such a central role means having to choose up-front the one that will be used throughout the design. This position tightly couples all future decisions to the physical part of the design. And it sets a predetermined path of implementation, resulting in a platform that is not easily changed later. With unforeseen market conditions appearing, this can create a situation that is very risky from a design perspective.

The development of next-generation ICs has been slowing in the current economic stall. The implication for embedded design is that being tied to an architecture that may not be changed or upgraded later could leave a project stuck quite literally.

The traditional approach of putting development of the hardware platform first, with soft aspects built in and locked down, has created a false sense of security by regarding time to market as an important product differentiator. The reality is that the value that differentiates a product device intelligence, or “IP” becomes tied to a rigid platform. In this scenario, it’s the most difficult and costliest design element to change. So relying solely on this methodology could exclude options later when they are direly needed.

Design philosophies that rely on incremental, phased upgrades over time are likely to be quickly replaced with technologies that are more flexible at the design level and can help companies survive market shifts. There are likely to be solutions that offer more options by focusing on higher levels of system abstraction that are easily changed, instead of relying solely on the choice of processor. One can imagine what a focus based on higher level abstraction will look like considering recent trends in the industry.

Designs are softer, less processor-centric

Designs are not based solely on hardware anymore as the boundary between hardware and software becomes increasingly integrated. This trend has been facilitated by the advance of hardware technology itself.

Mainstream embedded designs are moving away from processor-centric solutions and towards more a “‘soft-centric”’ approach.

Low-cost, high-capacity FPGAs have the potential to change the way we do design by allowing what was once manufactured into a device as part of the physical hardware, to now be programmable. This ‘soft-design’ focus in product development makes a lot of sense. Separate the device intelligence from the physical hardware into which it is programmed and avoid many of the trappings long associated with a hardware dependent solution.

FPGAs are becoming more popular as their capabilities improve and they’re easier on the budget. Expanding soft design of architectural platforms now includes an increasing amount of what were once the hardware aspects. By bringing as much hardware as possible into the programmable realm, iterative approaches that allow experimentation of ‘what if’ scenarios without increasing the design time can be explored, This allows you to explore different ways of achieving results that are more cost-effective without being committed to any specific form of implementation.

An additional benefit is that soft design can start before the hardware platform is designed. It can continue after the hardware is designed, and even after it reaches customers. Programmed intellectual property is becoming the most valuable part of design and giving rise to architectural flexibility with smaller, more adaptable boards.

The implications for a soft-centric approach to electronic systems extends beyond the software. Not only can the software be upgraded in the field, but the hardware can too.

Freedom from hardware commitment

Device IP that can then be programmed into the system, rather than manufactured on the board will offer the most advantages in future embedded designs. By having a level of programmability built-in, it’s possible to abstract many complexities of the system into a software layer that can sit on top of the processor. This layer – essentially a hardware wrapper – acts as a configurable piece of hardware that is the processor interface for memory and peripherals.

Within the right design environment, this layer can combine with matching software compilers and libraries of pre-verified embedded IP. This creates an embedded development system that is “vendor neutral” and directly linked with the design capture and board development stages.

Reprogramming of the FPGA to change the hardware wrapper allows the engineer to swap out one processor for another without having to modify the rest of system hardware. The obvious advantage to this approach is that the system could be started with one processor and moved to a faster device later if performance is needed. That crucial soft IP composed of programmable hardware and embedded software can now be developed independently of the hardware platform, removing the traditional problems caused by having to create physical hardware first.

Focus on core functions

Because low-level design considerations are now taken care of by the design system itself, focus can be redirected toward developing a design’s core functional elements using high-level capture interfaces. Even HDL entry can give way to simpler forms of embedded design capture where the level of design abstraction is raised, such as C. Design flow that was entirely dependent on processor and hardware specialists can be tackled by hardware and software engineers.

Using this approach, a project is better positioned for change and efficiency because the focus is off processor choice and managing all the low-level details surrounding it. Complexities that were once the inherently difficult part of the traditional design approach (such as board design) are downgraded appropriately to something more manageable, and focus is once again back on product differentiation and innovation.

Software combined with hardware becomes an intrinsic part of the new unified design paradigm. All that is required is a design environment that supports a single, unified design approach that can fully harness large-scale programmable devices.

Tools and technologies that deliver

Separation of design functionality from the processor requires a design platform where the hardware is not the primary consideration. Ideally, all design domains are presented as a single, unified flow. True design co-operation between domains can exist then because barriers between the processor and software are gone. This makes the task of moving design elements between software and hardware far simpler.

An engineer can set up a design environment where a reconfigurable hardware platform is used for the crucial debugging and updating phase of development. This would provide the freedom to experiment with various vendor devices and swap I/O hardware in and out. All the necessary tools for every aspect of electronic design would be included processor-independent embedded coding and debugging, mixed schematic and HDL-based FPGA design and synthesis, as well as full PCB layout. Software engineers with only a basic understanding of hardware could use it. Hardware engineers can focus on designing and prototyping unique design elements easily because not only would the software be upgradable, but the hardware as well.

A strategy that simplifies the design process by raising the abstraction level above the processor is a viable next step toward more flexible embedded design solutions. With downtrends challenging an industry that is also becoming more complex, the pressure has never been greater to break free from old mindsets. Processor choice will always be important. However, it’s time to make the primary design considerations achieving better innovation through a single design flow that is sustainable in the long run. ■