Eric Vittoz - IEEE

TECHNICAL LITERATURE
the launch of the Internet Time, a new decimal time
concept. Instead of dividing the virtual and real day
into 24 hours and 60 minutes per hour, Swatch's Internet
Time system divided the day into 1000 “beats”.
One of the goals of the system was to simplify the
way people in different time zones communicated
about time, mostly by eliminating time zones altogether.
Internet Time was also based on a new Meridian
(as opposed to the Greenwich Meridian) going
through Swatch’s office in Biel, Switzerland and is
called the BMT Meridian. So in addition to the standard
time format, the digital Swatch would also display
beats prefixed with an @ sign.
B. Need for Enhanced Display Technologies
Microcontrollers were first designed into watches with
analog and digital displays. Microcontrollers opened
new possibilities but also new needs especially on the
display side.
Higher end brands such as Omega and Rado have
also created models with mixed-mode displays or
specialty displays (e.g., full-dial LCD display with a
hole in the middle for the watch hands). Displays
available on the market didn't always meet the esthetical
standards (i.e., contrast, color) or physical
requirements (i.e., viewing angle, shape) of the
watchmakers. In 1986, EM Microelectronic installed
an LCD production infrastructure and started production
of LCD displays simultaneously for the watch
industry and for other industrial segments (e.g., avionics).
Initially producing display in TN technology, the
activity has since been diversified. Besides watch
applications, the company’s displays are widely used
today in white goods, portable electronic devices,
computer peripherals etc. In its latest move, still aiming
at miniaturization and increased design flexibility
for watches, EM Microelectronic and Asulab, the
Swatch Group’s corporate R&D lab, have co-developed
a flexible plastic LCD display technology (fig. 4).
VI. From Minimal Complexity Watch
Microcontrollers to Body Care Devices
A. 4-bit Microcontroller Gives the Tone
For some watch applications, an 8-bit microcontroller
was over-dimensioned, both from the point of view of
product cost and capability. In 1992, EM Microelectronic
asked the CSEM whether it would be feasible
to realize a 4-bit low-power microprocessor architecture
with no more than 1mm 2 footprint in a 2µm analog
low power technology (called ALP-2). The task
was given as diploma work to a student who came up
with the µPUS (acronym for microprocesseur ultrasimple)
architecture and the result caught the interest
of ETA who was looking for a solution for Swatch's
Musicall (fig. 5), a wristwatch featuring an alarm function
and playing a 7 tone melody. Japanese micro-
Fig. 5: 4-bit µPUS Microcontroller in Swatch Musicall and
electronic body care devices
controller alternatives were able to output only two
frequencies. EM Microelectronic built the microcontroller
and the first Musicall watch was launched in
1993 by Nicolas G. Hayek and French electronic
music composer and performer Jean-Michel Jarre in
the Palais de I’Unesco in Paris.
Several versions of µPUS-based microcontrollers
have been realized subsequently for different multifunctional
watches. Today this microcontroller family
is still at the heart of most analog quartz chronograph
watches made by Swatch and ETA's analog quartz
chronograph calibers.
B. Low Voltage in Body Care Devices
Expanding from watches into other portable, batteryoperated
applications, EM Microelectronic introduced
its first sub-1.0V microcontroller in 2004. The EM6682
is a 4-bit microcontroller with a voltage operating
range of 5.5 down to 0.9V. Sub-1Volt operation in this
circuit was achieved without artificial means; the
entire internal circuitry is running down to the lowest
voltage. Taking into account the discharge characteristics
of a 1.5V AA battery, a microcontroller operating
down to 0.9 volt will be able to extend the battery
life by 50%, compared to a 1.2V circuit (fig. 6). The
key point with such a technology is not only the
increased battery life-time, but also the fact that
devices can be operated with a single cell, instead of
two, which allows increased miniaturization and
36 IEEE SSCS NEWS Summer 2008