I have spent a fair amount of my formative years in and around the field programmable gate array (FPGA) industry.  I participated in the evolution of FPGAs from a convenient repository for glue logic and a pricey but useful prototyping platform to a convenient repository for lots of glue logic, an affordable but still a little pricey platform to improve time-to-market and a useful system-on-a-chip platform.  There was much talk about FPGAs going mainstream, displacing all but a few ASICs and becoming the vehicle of choice for most system implementations.  It turns out that last step…the mainstreaming, the death of ASICs, the proliferating system-on-chip…is still underway.  And maybe it’s just around the corner, again.  But maybe it’s not.

FPGA companies (well, Xilinx and Altera) appear to be falling prey to the classic disruptive technology trap described by Clayton Christensen.  Listening to the calls of the deans of Wall Street and pursuing fat margins.  Whether it’s Virtex or Stratix, both Xilinx and Altera are innovating at the high end delivering very profitable and very expensive parts that their biggest customers want and pretty much ignoring the little guys who are looking for cheap, functional and mostly low power devices.

This opens the door for players like Silicon Blue, Actel or Lattice to pick a niche and exploit the heck out of it.  Be it low power, non-volatile storage or security, these folks are picking up some significant business here and there. 

This innovation trap, however, ignores a huge opportunity that really only a big player can address.  I think that the biggest competitor to FPGAs is not ASSPs or ASICs or even other cheaper FPGAs.  I think that what everyone needs to be watching out for is CPUs and GPUs. 

Let’s face it, even with an integrated processor in your FPGA, you still really need to be a VHDL or Verilog HDL developer to build systems based on the FPGA.  And how many HDL designers are there worldwide?  Tens of thousands?  Perhaps.  Charitably.  This illuminates another issue with systems-on-a-chip – software and software infrastructure. I think this might even be the most important issue acting as an obstacle to the wide adoption of programmable logic technology. To design a CPU or GPU-based system, you need to know C or C++.  How many C developers are there worldwide?  Millions?  Maybe more.

With a GPU you are entering the world of tesselation automata or systolic arrays.  It is easier (but still challenging) to map a C program to a processor grid than sea of gates.  And you also get to leverage the existing broad set of software debug and development tools.  What would you prefer to use to develop your next system on a chip – SystemC with spotty support infrastructure or standard C with deep and broad support infrastructure?

The road to the FPGA revolution is littered with companies who’s products started as FPGA-based with a processor to help, but then migrated to a full multi-core CPU solution dumping the FPGA (except for data path and logic consolidation).  Why is that?  Because to make a FPGA solution work you need to be an expert immersed in FPGA architectures and you need to develop your own tools to carefully divide hardware and software tasks.  And in the end, to get really great speeds and results, you need to keep tweaking your system and reassigning hardware and software tasks.   And then there’s the debugging challenge.  In the end – it’s just hard.

On the other hand, grab an off-the-shelf multi-core processor, whack together some C code, compile it and run it and you get pretty good speeds and the same results.  On top of that – debugging is better supported.

I think FPGAs are great and someday they may be able to provide a real system-on-a-chip solution but they won’t until FPGA companies stop thinking like semiconductor manufacturers and start thinking (and acting) like the software application solution providers they need to become.