Introduction to the Storm System

1. Microcontroller

  • Ultra low power

    The Storm System achives a "roughly equal to the current best" low power performance. We choose not to go lower power since that will sacrifice functionality.
    This choice is motivated by the observation that it is easier to predict the effects of increased energy efficiency – longer battery life – whereas the effects of a richer set of capabilities provides a more interesting area for research.

  • Architecture

    The Storm System decideds to use ARM architecture.
    ARM architecture has a wide range of benefits including low energy cost, widespread popularity, better adaptability and more.
    Among ARM, an ARM Cortex-M4 is the ideal candidate at this point.

  • Peripherals

    It is essential for the microcontroller to have sufficient GPIO and peripheral blocks, while simultaneously remaining low power and small.
    For this reason, the Storm platform uses an MCU that provides a wealth of peripherals, along with 12 indepen- dent DMA channels allowing most of these peripherals to be used without CPU intervention.

  • Advanced OS Support

    The Storm System provides a Memorry Protection feature to make over-the-air programming reliable.
    The key change here is that a malicious or logically in- correct payload is unable to bypass the grenade timer by direct manipulation of control registers – something that was possible with watchdog timers in previous generations of embedded wireless platforms.

2. Radio

  • Transceiver chip

    There are two major factors when considering the transceiver chip for constrained embedded wireless systems.
    The first ane the most important one is the time it takes for the radio to exit its low power sleep mode and transmit or receive.
    The second is the current drawn during transmission and reception.
    After the consideration and analysis, the possibility of automatic CS- MA/CA combined with the better power and signal strength characteristics was enough to convince us that the newer Atmel radio chip was the better choice.

  • Integration

    To reduce size, BOM cost and variability during manufacture, we decided to use a single integrated balun/filter that was designed specifically for matching the RF233 to a 50 Ω single-ended antenna since The radio subsystem extends beyond the choice of transceiver, and determines how the antenna will be matched and con- nected to the radio.
    The second major choice in the Storm’s radio subsystem is the use of an antenna diversity switch instead of using an assembly-time capacitor location as selector.

3. Flash

  • The storage platform storage is critical for many applications, and current generations of wireless platforms often utilize flash chips that are unable to operate at the low end of the system’s supply voltage range.
    Fortunately, at the time of design, Adesto Technologies had just released a new 64 Mbit flash chip - the AT45DB641E - that operates over a supply range of 1.7V to 3.6V. This de- velopment allows for the platform to truly run at low volt- ages while still retaining the ability to operate at higher voltages, a hitherto unreachable goal.

For a more detailed design process and analysis, along with the measurements of the energy performance of the Storm Platform, please read our publications about the Storm