Helpful Hot-Rodding Hints
Most of us engineers are at least closet hot-rodders. It’s in our DNA. No matter how good a contraption is from the factory, we just can’t resist the temptation to tweak a few things in our own special way, and often that’s all about speed.
FPGA design, it turns out, is a big ‘ol blank canvas for hot-rodding. Even though we (fortunately) don’t have glossy convenience-store magazines adorned with scantily-clad models standing next to the latest tricked-out dev boards, FPGAs have all the tools we need to rev our creative motors in the never-ending quest for that extra little bit of personalized performance.
But, where do we start? Do FPGAs have a set of go-to hop-ups? Is there a “chopping and channeling” baseline for programmable logic design?
It turns out the answer is “yes.” And, just to get you started, here are five tips for turning up the boost on your next project:
Ecosystem for Interposer-based Design?
We’ve talked a lot lately in these pages about the impending demise of Moore’s Law. Consensus is that, somewhere around the half-century mark, one of the most astounding prophecies in human history will have finally run its course. Next year, we’ll have a round of FinFET devices that will be so exotic and expensive that only a handful of companies will be able to use them. In the decade that follows, we may or may not reach 10nm and 7nm production - using either esoteric unlikelies like EUV or extreme-brute-force multi-patterning techniques - to solve just some of the multitude of barriers to continued downscaling.
Sci-fi techniques like carbon nanotubes, graphene-based devices, quantum computing, and that other-one-you-read-about are so far from production practicality that we may not see any of them in widespread use in our lifetimes. While incredible research shows great promise for many of these ideas, they are all back in the silicon-equivalent of the early 1960s in their evolution. The time and engineering it will take them to catch up with and eventually surpass what we can do with silicon today is substantial.
Hey, There’s LUT Fabric in my SoC!
The idea of processors and FPGAs working together is exactly as old as the idea of FPGAs. Perhaps older, in fact, because even the prehistoric pre-FPGA PLDs often showed up on CPU boards - palling up with the hot processors of the day (which boasted 8 full bits of bone-crushing capability - at speeds of over a megahertz!) Of course, those programmable devices were mostly doing “glue logic” work - connecting up things that weren’t easy to connect otherwise.
Since those early days, processors and programmable logic have enjoyed a long and romantic partnership - spending long lazy days gazing lovingly into each other’s IO ports, exchanging data (and some control signals as well), and enriching each other’s lives through mutual cooperation. The partnership was never equal, though. Processors got all the glamour and recognition. Debutante CPUs would burst onto the red carpet with wider words and faster clocks, and they’d barely give a nod to their loyal FPGA companions who worked silently in the shadows, doing all the dirty work.
The Truth About Engineering Talent
People who are sports fans often watch in amazement when a superstar athlete gets a contract worth tens of millions of dollars. “Why,” they ask, “is kicking or throwing a ball worth that kind of money? And with millions of talented people who spend their entire lives practicing this sport, why is this particular one deserving of that kind of compensation?”
We all wonder this.
Then, we realize that, in many cases, most of the crowd gathers primarily to watch the performance of that one superstar. Take him or her away and it’s just another game. To prove that, watch what happens in the US when a professional sports league goes on strike and the teams bring in temporary “replacement” players. The audience leaves in droves. People don’t watch on TV - except perhaps from schadenfreude. Even though the replacement players are top-notch professionals in their own right, they don’t bring the superstar magic to the performance. The result is simply ordinary excellence, with all too many tell-tale signs that even skilled professionals are just human after all.
Advanced vs. Established Process Geometries
It's time to saddle up and ride into the semiconductor sunset! Whether you're hitchin' your wagon to a young whipper-snapper node, or lassoin' a long-in-the-tooth workhorse process, the time it takes to get your IC design up and out of the corral may depend more on the software you use to verify your design than on the silicon itself. In this week's Fish Fry, Mary Ann White (Synopsys) and I get down to the very heart of semiconductor design: process geometries. We have ourselves a good ol' time chatting about challenges of FinFET designs, the tricky bits of working with both advanced and established process nodes, and how the right tools can make all the difference when it comes to winning the big product-to-market rodeo.
Is 20nm the Forgotten FPGA Node?
28nm is a calm, mature node. Sure, everyone was excited when it was the first to reach modern price, performance, and cost levels. We applauded when ARM processing subsystems were integrated into 28nm FPGAs, creating a new class of device. And there were accolades when 28nm debuted interposer-based 2.5D packaging techniques. There is even a nice page in the scrapbook where 28nm SerDes transceivers hit 28Gbps speeds - a nice 28/28 symmetry that made everyone feel all warm and fuzzy.
We all know and love 28nm. It’s out there - proven and in full production, making our real-world designs really work today. It’s great! You really can’t go wrong with any of Xilinx’s or Altera’s robust 28nm offerings - from cost-optimized, higher-volume Kintex and Arria chips up to the biggest, fastest, most feature-laden Virtex-7 and Stratix V devices, 28nm FPGAs have you covered.
What if it Happened Again?
We sit here in our dazed, progress-drunk technology buzz looking back at the half-century rocket ride that transformed not only our industry and engineering profession, but also all of modern civilization. Nothing in recorded history has had as much impact on the world as Moore’s Law. It has re-shaped global culture, dramatically altered politics, and even affected fundamental aspects of the ways human beings work, think, feel, and relate to each other. If this weren’t the single biggest change driver in the history of civilization, it was right up there with democracy, monotheism, combining caramel and chocolate, and some other really heavy-hitters. Innovation in electronics has spilled over into just about every other aspect of our collective lives, and the change is profound.
But, what if it happened again - not in electronics this time, but somewhere else?
To answer that question, we should look at what caused Moore’s Law in the first place. It was a single innovation, really. Just one idea.
Are FPGAs Harbingers of a New Era?
The title may have put you off. In fact, it probably should have. After all, most of us in the press/analyst community have - at one time or another during the past decade or two - been walking around like idiots wearing sandwich signs saying, “The End is Nigh!” And, we got just about as much attention as we deserved. “Yawn, very interesting, press and analysts, and now back to planning the next process node…”
It gets worse. Predicting that Moore’s Law will end is pretty much a no-brainer. It’s about as controversial as predicting that a person will die… someday. There is obviously some point at which the laws of physics and the reality of economics will no longer allow us to double the amount of stuff we put on a single chip every two years. The question is - when will we reach that point, and how will we know we are there?
Lattice's iCE40 Ultra and Xilinx at
Bienvenido a Fish Fry! Welcome to this week’s field programmable Fish Frying festivities. First to join the podcastin' party is Joy Wrigley from Lattice Semiconductor. Joy and I discuss how FPGAs are breaking into the IoT scene and why low power will make all the difference in tomorrow’s mobile designs. Joining the fun next is Barrie Mullins from Xilinx. Barrie and I chat about how Vivado is playing a bigger role in this year's X-fest and why this conference isn't just for FPGA designers.
The Quest for Truth in Engineering
“Why don’t they just put solar cells on top of cars and power them that way?”
His tone implied that the engineers designing cars were just idiots, and he was sure he could do better - with just this one idea. I was going to answer with some helpful information about the amount of energy required to operate an automobile, the amount of energy collected by even idealized solar cells, and the amount of area available on top of a typical vehicle. I didn’t get the chance.
His friend interrupted, “Well that’s just the government shutting them down. The oil companies have the government in their pocket, and they’re not about to let anyone develop technology like that. It’s the same with that 200 MPG carburetor that guy in Florida invented…”
Now, I was more hesitant to speak. I wanted to explain that modern, sensor-driven, computer-controlled fuel injection systems did a much better job achieving near-ideal fuel-air mixtures than any carburetor could ever hope to accomplish. I didn’t get the chance.