of Pico Electronics Ltd
was a significant British computer maker who in the
1960s realised the need to progress its own semiconductor technology.
In 1966 the
established a facility in Glenrothes to manufacture Resistor-Transistor
, followed by the establishment of a MOS research laboratory.
Geoff Brookes, Alan Strath and George Stevenson relocated from
Borehamwood to Glenrothes to establish the MOS facility (1)
computer using MOS
technology, with George as the computer expert. In 1967 Elliott
Automation merged with English Electric,
and when GEC bought English Electric in 1969 they decided to close
their production plant in Glenrothes.
Alan Strath had predicted the closure in 1967. "Since English Electric
had recently completed a new microelectronics factory in Chelmsford,
Essex, we expected that the Glenrothes facilities would be closed, so
we successfully offered our services to General Instrument
to establish a new facility". The Glenrothes facilities were
complemented by the Hughes Aircraft
factory that had been established in 1960 to produce
germanium and silicon diodes and transistors, before moving into
MOS design and production during 1967/1968.
In 1970 four General Instrument design staff left
to form Pico Electronics Ltd. They were George Stevenson, David
Harry McLennan and Les Leech. George was the Director of Engineering
and the others were young, bright designers. All had previously been at
Elliott Automation. Moses Shapiro, the CEO of GI advanced some startup
capital on the basis that GI would get exclusive rights to the
manufacture of the single chip calculator ICs that the new
company were planning
to develop. They set up in a rented office in the
Postgate in Glenrothes and very quickly put their design ideas into
practice. The team already had a significant legacy in successful
calculator chip design with one of the last jobs they had completed in
GI being a five chip set for a Facit
calculator. The team had designs
calculators going back to the Elliott days for Bell
Location of Pico's First Design
David Campbell remembers the first IC development at Pico Electronics.
"We were certainly not aware that any other company in the world was
working to develop a single chip calculator at that time. George
Stevenson was the project leader and it was he who came up with the
advanced and novel architecture used in that first calculator chip. I
have always admired that achievement and give him full credit for it.
The other guys, myself included had the job of converting his design
ideas to a working chip using a 4 mask 10 micron metal gate PMOS
process. My own contribution was the design and layout of the
program ROM and the dynamic RAM memories and the timer. This first
machine was really advanced for its time, because it was a Reduced
Instruction Set (RISC) processor. For example an 8 bit floating point
addition of 2 numbers required just one line in the ROM. The whole
program for the calculator was only 70 lines of ROM. The ROM was wide
to allow the different parts of a calculation to be done in parallel.
This meant that although the clock speed of the ROM was very low, the
time to perform calculations was much quicker than other calculator
chips which emerged in the years after our chip. The layout of the chip
was done by hand because there were no software design tools for layout
at that time. The layout was done by drawing the 4 layers of the PMOS
transistors at 500 X scale onto a stable mylar film with a grid
pattern. The transistors were represented by rectangular boxes for the
drain, source, gate and contact, and the metal
interconnection layer was drawn as rectangular lines. There
was also no computer simulation of the design prior to layout. To prove
the design concept we built a fully functional but not very reliable
breadboard using off the shelf TTL logic chips soldered onto a
of stripboards which were just connected together by wires."
David Campbell continues. "The Pico calculator chip had stored program
memory in the form of a ROM
which worked in the same way as the ROM inside a microprocessor to
perform a series of pre-programmed instructions. Remember in those days
there was no OTP which could allow a microprocessor chip to be
re-programmed. All the initial single chip microprocessor applications
wired mask ROM code. Applications which used external ROM or RAM for
program memory and scratch pad memory were not single chip
applications". Re-programming was still possible through a change in
PICO1 Chip Layout
The design was completed very quickly and fabbed at GI's
David remembers the fab cycle time being a few weeks. GI's
those days was state of the art and the design worked very early on.
Towards end of 1970 they had working silicon and a working calculator
prototype to demonstrate to potential US and Japanese customers. Very
quickly the Monroe Calculator Company (Litton Industries) of New Jersey
signed up to become Pico and
also designed the styling and all the electronics for Monroe's
models. Later in 1971 or 1972 Clive Sinclair also used Pico's
his calculators Sinclair
. (Alan Strath remembers Clive Sinclair visiting GI in
Glenrothes not knowing anything about the technology, and two weeks
later he was back, an expert !)
Intel announced their 4004 microprocessor in
November 1971 Intel 4004 Website
This had been designed into a Busicom calculator earlier in 1971 but
had been an exclusive design. If you compare Pico to Intel in
those early days, the guys who
formed Pico had the combined experience of computer mainframe
architecture, the Elliott task to
create an 8 bit computer in MOS, and significant design experience on
for a number of different calculator manufacturers. Their vision in
setting up their independent company was to develop single chip
processor ICs for calculators. Intel had a couple of designers in a new
lab who happened to take on a design from Busicom. It was Busicom's
idea to develop a calculator platform on which a wide range of
calculators could be made. However in reality they couldn't develop
follow-on machines with better capabilities, and couldn't compete with
other solutions coming onto the market. It was this failed
strategy that encouraged Intel to seek alternative markets for their
device. Calculators were becoming the largest single market for
semiconductors and attracting increasing competition.
Calculator CCA With Intel
III With Pico/GI Chip
Instruments had also been designing more integrated versions of their
ICs for calculators, however they were behind Pico. David Campbell
remembered visiting TI in Houston
after the Pico chip had been in production at GI for some time.
"I remember visiting TI in Houston with George Stevenson in 1972 after
our chip had been in volume production for some time when they told us
about their one chip calculator. The chip size was huge and it was very
slow compared to ours. They called a chip a "Bar" rather than a die
which I thought was odd at that time. The visit was arranged by Monroe
response to TI's effort to try to replace our chips in the Monroe
If you examine Pico's patent 4,001,556
version filed in March 1971, US
version in July 1971) and compare with the often cited patents of Intel
and 3,753,011 Intel 4004 Patent Webpage
TI patents are the only ones to
make claims on single chip devices but Pico's pre-dates TI's and is
more integrated, having the processor on chip with ROM and RAM.
George Stevenson and the others originally came up from Borehamwood to
Elliott in Glenrothes their task was to create an 8-bit computer in MOS
technology. Borehamwood was the research centre for Elliott, a maker of
mainframe computers, so George already had a computer architecture
he architected the single chip calculator IC.
Much later on, TI
invested a huge amount of effort to get Michael Cochran and Gary
Boones' patent 6650317
filed which must have
been in response to the claims of Gilbert
Hyatt on the
invention of the microprocessor. The patent is incredibly well
researched and cites a massive amount of prior claims and publications
including George Stevenson's "Single Chip Calculator" and "documents
produced as exhibits to the deposition of George Earley Stevenson".
Michael Cochran and TI's
Single Chip Calculator
Manufactured and Marketed Pico's Chip Designs
George Stevenson and his team moved on to more complex chips including
a single chip scientific calculator and went on to design all of GI's
calculator chips. Pico eventually moved from the rented office in the
Postgate to the vacated Elliot Automation MOS Laboratory building on
the Eastfield Industrial Estate. Pico Electronics Ltd is still in
existence as part of X10 Ltd
David Campbell and Pico
continued to produce a number of innovations including the de-facto X10
for Home Automation. George Stevenson and Les Leech are still at X10 in
Hong Kong. Further Pico and X10 history can be found at Pico
and X10 History.
Pico Electronics still own the Elliott building, however most
business is now operated out of Hong Kong. Until his recent retirement,
Harry McLennan still worked at Pico in Eastfield. Another early Pico
employee, Dave Thompson who worked with David Campbell on the first X10
automation chips is still at Eastfield. David Campbell has been an
independent IC design consultant for a number of
General Instrument in Glenrothes continued to produce a number of
Pico's calculator IC designs and other consumer chips including X10 and
their US Hicksville NY facility to Arizona,
from which they spun out the PIC microcontroller business into
Microchip Technology in 1989. The GI wafer fab in Glenrothes still
operates as an independent wafer foundry.
Created Sep 2006, last updated Sep 2010.
2006 to 2010
(1) Alan Strath remembers, "I
Automation in 1965. We started up in Scotland in 1966 and I think the
EE takeover was in 1967.
started with GI in the same year, with temporary accommodation in
adjacent Glenrothes Development Corporation terraced houses in South
Parks road. George and some of his
recruits worked on designs on the ground floor while we pursued the
conversion of a standard advance factory as a semi plant and ordered
equipment. The Daily Express printed that the MD shared a bedroom in
the house with his secretary ! I
believe that GEC took over EE in 1968 or 1969, although I'm not sure.
may know, Elliott Auto had taken a licence with Fairchild,
for DTL. During this period we met Robert
Noyce, CEO of Fairchild and Gordon Moore, R& D manager. They left
Fairchild saying that it had mushroomed out of control.
The production unit at Queensway closed
in 1968 or 69 and partially moved to the R&D factory at Eastfield
An interesting if trivial footnote is that the Elliott Automation
production facility was established in part of the Cadco "pig factory"
in Queensway Industrial Estate. Cadco was an investment by the actor George Sanders.
Sanders was well known for playing the "cad" in films, and in
a remarkably ill-conceived business venture in the early '60s, having
always harboured dreams of becoming a tycoon, threw his name and
most of his money into a sausage-making scheme that went belly-up,
taking his company, Cadco Ltd., with it. He
was ruined financially and barely escaped prosecution.
The first electronics related facility in Glenrothes was actually
Beckman Instruments in 1958. Interestingly it was Beckman Instruments
who created the Shockley Semiconductor Laboratory division in Mountain
California in 1956. This was the very first Silicon Valley company and
the famous "treacherous
eight" who later founded Fairchild
including Gordon Moore, Robert Noyce and Jean Hoerni. Shockley had
moved west to be with his ailing mother who lived in Palo Alto.
The Royal Digital III retailed for $150 in 1971, equivalent to $746 in
2006, which is a huge figure for a handheld calculator. The Royal
Digital I desktop retailed for $250, $1244 in 2006. The advertisement
below is either from late 1970 or late 1971.