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How the FPGA Came To Be, Part 7: Did General Electric invent the PLD and EPLD in 1971?

My long running series titled “How the FPGA Came To Be” (referenced below) chronicles the development of programmable logic starting with programmable diode matrices developed and marketed by Harris Semiconductor starting in the mid-1960s. These diode matrices along with a Mask Programmable Logic Array (MPLA) from National Semiconductor were the inspirations for the short-lived Intersil IM5200 Field Programmable Logic Array (FPLA) and the more successful Signetics 82S100 FPLA, both introduced in 1975. John Birkner streamlined the FPLA concept, leading to MMI’s introduction of the first PAL in 1978. These were all fuse-based devices based on bipolar semiconductor processes, although the “fuse” for the Intersil device was actually a bipolar transistor that shorted out due to aluminum migration during programming and was therefore really an antifuse. Altera developed and introduced the first erasable PLD, the EP300, in 1984.

Altera made a short, 93-second video to celebrate its recent semi-independence from Intel, which previously bought the company in 2015. The video chronicles the company’s history and claims, rightfully, that Altera developed the first erasable PLD. I’d seen this video and was a bit nonplussed by its breathless marketing claims, but hey, that’s marketing from the minds of people who are not LUT heads.

More recently, Altera started advertising the video on LinkedIn with this image:

Altera made a 93-second video about its history and is using this image to advertise it. Yes, that’s Leonard Nimoy on the left. He provided celebrity advertising for Altera in the 1980s. Image credit: Altera

Altera’s LinkedIn posting that advertises this video then led to a bizarre interchange on LinkedIn between myself and Aurelian Lazarut, CTO at Adaptive Design ltd. Lazarut asserted that Altera did not invent the erasable PLD. General Electric (GE) did, in 1971. That was a shocker! Here’s the verbatim LinkedIn conversation that followed, starting with Altera’s initial LinkedIn post:

Altera on LinkedIn

“FPGAs have come a long way since the early 80s

“The first FPGA had only 64 logic cells. [Editor’s note: That was the Xilinx XC2064]

“Modern FPGAs can contain millions of logic cells, enabling complex AI and machine learning applications.

“FPGAs are used in everything from space exploration to medical imaging

“Find out more about our history in FPGA leadership in this video

“Innovators, what’s your favorite application of FPGA technology?”

Aurelian Lazarut, CTO at Adaptive Design ltd.

“The first FPGA was invented by Ross Freeman (R.I.P) from Xilinx as far as everybody knows. US patent US4870302A (https://patents.google.com/patent/US6191610B1/en)

“Does anyone have a link to patent before this one? please share.

“Maybe Altera marketing department didn’t get the memo…”

Steve Leibson, Principal Analyst Emeritus, Tirias Research/Editor/B2B Technology Marketer/Storyteller/Content Ninja/Evangelist/Engineer/IEEE Senior Member/Poet

“Aurelian Lazarut: If you listen to the very short video, Altera only claims to have made the first erasable PLD, not an FPGA. In fact, Altera purposely refused to use the term FPGA until the early 1990s. During the interim, Altera made complex PLDs based on replicating the PAL architecture. Eventually, Altera was forced to accept the scaling realities of CPLDs and started making FPGAs. The AMD/Xilinx and Altera FPGA duopoly has continued now for 35 years.

“I agree with you. The above graphic does not accurately represent the linked video, but it’s great to be reminded that Leonard Nimoy once shilled for Altera, ‘The Only Logical Choice.’”

Aurelian Lazarut, CTO at Adaptive Design ltd.

“It was in the text description (not in the video) they took it out. You came late to the party. Just trying to set the record straight. Btw they didn’t invent the EPLD either (listen to the voice in the video) it was GE (https://en.wikipedia.org/wiki/Programmable_Array_Logic) who cares about facts anyway on this flat earth…”

Steve Leibson, Principal Analyst Emeritus, Tirias Research/Editor/B2B Technology Marketer/Storyteller/Content Ninja/Evangelist/Engineer/IEEE Senior Member/Poet

“Aurelian Lazarut: Altera did invent the erasable PLD, as claimed in the video. Earlier PALs were burn once. I had a paper cup full of one-time programmable PALs on my desk in the early 1980s. Please see my 6-part series on FPGA history in EEJournal. Latest article just hit today.”

Aurelian LazarutView, CTO at Adaptive Design ltd.

“We can’t change the past as we please…

“In 1971, General Electric Company (GE) was developing a programmable logic device based on the new Programmable Read-Only Memory (PROM) technology. This experimental device improved on IBM’s ROAM [read-only associative memory] by allowing multilevel logic. Intel had just introduced the floating-gate UV EPROM so the researcher at GE incorporated that technology. The GE device was the first erasable PLD ever developed, predating the Altera EPLD by over a decade. GE obtained several early patents on programmable logic devices.[5][6][7]”

“The true part is they made the first in CMOS PLD I think (not sure) but they don’t say it in the video.

Steve Leibson, Principal Analyst Emeritus, Tirias Research/Editor/B2B Technology Marketer/Storyteller/Content Ninja/Evangelist/Engineer/IEEE Senior Member/Poet

“Aurelian Lazarut: “We can’t change the past as we please” I could not agree more.

“I’ve looked at the patents cited by the Wikipedia article you quoted. GE Solid State was never a factor in MOS development, and I find no evidence that GE ever produced an EPROM, much less an erasable FPGA. It appears that most of the patents you cited, including the drawings, are devoted to fusible links, as found in bipolar devices like Harris diode arrays and MMI’s PALs.

“So, it appears our disagreement centers around the word “invented.” GE’s patent certainly envisions FPGAs and even erasable FPGAs, but I find no evidence that GE ever had the process technology to produce such a complex device, especially not in 1971. After all, Intel first disclosed the 1702 PMOS EPROM in November 1971. How long do you think it would take GE to come up with a workable MOS process after that?

“My information about MOS development comes from Bassett’s ‘To The Digital Age,’ the definitive work on the subject with a ton of references. You’re quoting Wikipedia to me. Wikipedia is a great resource, but hardly a definitive one. I use Wikipedia a lot, but always need to confirm its ‘facts’ with more definitive references.”

(Note: If you’d like to see an opposite view crediting Altera with the first reprogrammable PLD, check out this Wikipedia entry about the FPGA: Altera was founded in 1983 and delivered the industry’s first reprogrammable logic device in 1984 – the EP300 – which featured a quartz window in the package that allowed users to shine an ultra-violet lamp on the die to erase the EPROM cells that held the device configuration.”)

In subsequent research, I found that the ideas about GE inventing the erasable PLD from the Wikipedia entry have spread across the Internet and can be found in reddit discussions and elsewhere, always citing the Wikipedia entry. People in my inner circle of PLD and FPGA experts have never heard of GE as a PLD developer or supplier. Together, we’ve got more than 100 years of PLD and FPGA experience.

I’ve looked at the three GE patents cited in the Wikipedia entry for “Programmable Array Logic.” What I see are schematics of multi-emitter bipolar transistors, much like the input transistors of TTL devices in popular use at the time, joined by wires and fuses. What I don’t see are complete logic gates. The GE design is very much a bipolar design concept, similar in nature to the Signetics and MMI PLDs. It appears to me that GE simply threw Intel’s EPROM technology into the patent application as a possible embodiment shortly after Intel announced the 1702 PMOS EPROM in 1971.

As far as I can tell, this patent concept was never reduced to practice. GE’s commercial semiconductor division was making bipolar power transistors, diodes, triacs, and optoelectronic devices during that period. What few ICs GE produced were bipolar power devices, based on what I remember of that time and based on some Google-fu searches. GE subsequently bought Intersil in 1980 and RCA’s semiconductor division in 1985, and started to offer ICs after that, but GE’s CEO Jack Welch soon soured on the cyclic nature and transient low-profitability of the semiconductor business and nuked GE Solid State by selling all of it to Harris Semiconductor in 1988. In 1999, Harris Semiconductor spun out of Harris and renamed itself, resurrecting the name Intersil. Renesas bought the resurrected Intersil in 2017.

So, I guess the question of GE’s PLD and erasable PLD invention all boils down to your definition of the word “invent.” If I ask you who invented the telephone, I’d expect your answer would be “Alexander Graham Bell,” because his patent is upheld over many other comers. Yet Elisha Gray, engineer and co-founder of Western Electric, could certainly be considered the original inventor of the telephone, and is by some, but Bell’s patent has priority and Bell subsequently systematized the entire telephone industry.

If I ask you who invented the airplane, I’d expect your answer to be “Orville and Wilbur Wright,” but Brazil’s Alberto Santos-Dumont also has a claim as does France’s Victor Tatin. However, the Wright brothers didn’t just build a one-off airplane. They systematically developed their aircraft concepts and brought commercial airplanes to market, so we remember them as the inventors.

We will give Mr. Lazarut the last word in this LinkedIn conversation. He replied to my last message above a day later:

Aurelian Lazarut, CTO at Adaptive Design ltd.

“Steve,

“I’m not trying to minimize Altera’s achievements, just stating the facts. The claims of marketing departments have to water down a bit. The EP300 was the first CMOS erasable PLD (with some key improvements) [with a link to a 1984 EDN article announcing Altera’s EP300, referenced below].

“Altera’s doesn’t have to ‘cook’ any claims because they are great innovators and nothing will change that.”

I think Mr. Lazarut is harping about a mistake made by a lower-level marketing minion who writes blurbs for Altera’s social media accounts and possibly never heard the terms “PLD” or “FPGA” before joining the company. That person and their errors should not be mistaken for the official position of Altera’s marketing department. I suspect the blurb writer’s work may get more senior-level scrutiny in the future, possibly from the Altera legal department, which usually rides herd on these sorts of claims. Apparently, the FPGA claim that triggered Mr. Lazarut’s initial LinkedIn comment was deleted quickly, before I had a chance to see it. Someone caught the mistake and fixed it. The more senior marketing managers in those companies are fairly well aware of their industry’s history. (Full disclosure: I worked in the marketing departments of both Xilinx (for five years) and Intel FPGA (now Altera, for two years), and I wrote blogs for both companies.)

I’m glad Mr. Lazarut found the EDN article about the Altera EP300. Period EDN articles like this one by Andy Rappaport can be valid sources for facts because they were written at the time. However, even those sorts of references can be wrong. Some editors are more technical than others. I worked for EDN for 11 years and served as its Editor in Chief for three years. That was a few years before the founding of EEJournal.

Look, I’ve got no dogs in this fight, only facts, and my facts don’t come from Wikipedia. Did GE invent the PLD and the erasable PLD as the Wikipedia entry claims, or did it merely envision them through the patents? My inner circle advises me that there are plenty of paper patents that envision products or devices that were never built. I’m keeping an open mind. If someone can show me that GE did more than just write a patent or three, I’m happy to write another article that explains GE’s contribution to PLDs. What do you think? Leave your comments and ideas below.

References

How the FPGA Came To Be, Part 1

How the FPGA Came To Be, Part 2

How the FPGA Came To Be, Part 3

How the FPGA Came To Be, Part 4

How the FPGA Came To Be, Part 5

How the FPGA Came To Be, Part 6

Andy Rappaport, “First CMOS reprogrammable logic array specs low power and UV erasability,” EDN, May 3, 1984

Ron Wilson, “In the Beginning,” Altera, 2013

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