Michael P Andersen and David E. Culler

EECS Department, University of California, Berkeley

Technical Report No. UCB/EECS-2014-162

August 25, 2014

Over the course of the past decade, the evolution of ad- vanced low-energy microcontrollers has raised three ques- tions which this paper outlines and addresses. The first question is: Can a 32-bit platform be constructed that provides advanced features but fits within the energy constraints of a wireless sensor network? We answer this in the affirmative by presenting the design and preliminary evaluation of Storm – one such system based on an ARM Cortex-M4 that achieves 2.3μA idle current with a 1.5μS wake up time. The second question we answer is: Can this platform simultaneously meet the very different demands of both monitoring-type applications and cyber-physical systems? We demonstrate that this is indeed possible and present the design trade-offs that must be made to achieve this, yielding a module with a rich set of exported peripherals that fits in a 16mm x 26mm form factor. The final question explored by this paper is: If such a platform is possible, what new opportunities and challenges would it hold for embedded operating systems? We answer this by showing that the usage of modern 32 bit microcon- trollers requires reconsidering system architecture govern- ing power management, clock selection and inter-module de- pendencies, as well as offering opportunities for supervisory code and the coordination of common tasks without CPU in- tervention.

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BibTeX citation:

@techreport{Andersen:EECS-2014-162,
    Author= {Andersen, Michael P and Culler, David E.},
    Title= {System Design Trade-Offs in a Next-Generation Embedded Wireless Platform},
    Year= {2014},
    Month= {Aug},
    Url= {http://www2.eecs.berkeley.edu/Pubs/TechRpts/2014/EECS-2014-162.html},
    Number= {UCB/EECS-2014-162},
    Abstract= {Over the course of the past decade, the evolution of ad-
vanced low-energy microcontrollers has raised three ques-
tions which this paper outlines and addresses.
The first question is: Can a 32-bit platform be constructed
that provides advanced features but fits within the energy
constraints of a wireless sensor network? We answer this
in the affirmative by presenting the design and preliminary
evaluation of Storm – one such system based on an ARM
Cortex-M4 that achieves 2.3μA idle current with a 1.5μS
wake up time.
The second question we answer is: Can this platform
simultaneously meet the very different demands of both
monitoring-type applications and cyber-physical systems?
We demonstrate that this is indeed possible and present the
design trade-offs that must be made to achieve this, yielding
a module with a rich set of exported peripherals that fits in a
16mm x 26mm form factor.
The final question explored by this paper is: If such a
platform is possible, what new opportunities and challenges
would it hold for embedded operating systems? We answer
this by showing that the usage of modern 32 bit microcon-
trollers requires reconsidering system architecture govern-
ing power management, clock selection and inter-module de-
pendencies, as well as offering opportunities for supervisory
code and the coordination of common tasks without CPU in-
tervention.},
}

EndNote citation:

%0 Report
%A Andersen, Michael P 
%A Culler, David E. 
%T System Design Trade-Offs in a Next-Generation Embedded Wireless Platform
%I EECS Department, University of California, Berkeley
%D 2014
%8 August 25
%@ UCB/EECS-2014-162
%U http://www2.eecs.berkeley.edu/Pubs/TechRpts/2014/EECS-2014-162.html
%F Andersen:EECS-2014-162