Overview

ENS Box Architecture:

The ENS Box has two boards – the Slauson board which has the more-powerful Xscale processor and the high power (802.11) radio. There is the Saguaro board which has two low power processors (msp430) and the low power radio (CC2420 – IEEE 802.15.4/zigbee). The two processors have different duties – (1) MP – Management Processor that manages the overall system and controls the low power radio (2) SMP – Sensor Management Processor that connects to all the sensors and the flash. This combination makes the ENS box a very potent system with high computational capabilities while being able to adapt to low power needs.

TinyOS

TinyOS is an open source, component-based, event-driven operating system targeting wireless sensor networks. It is designed to be able to incorporate rapid innovation as well as to operate within the severe memory constraints inherent in sensor networks. It is the defacto OS used for most sensor network research in academia. TinyOS has been under development for about five years. There is a huge repository of components already available for use. Due to the inherent component-based structure of TinyOS, new applications could be rapidly developed by wiring together existing components if a port of TinyOS exists to the platform under use.

TinyOS presently works on all the sensor mote platforms – mica2 (ATmega128L), micaz, telos (MSP430), Atmel AVR, with different flash, radio chips and sensors on board.

Accomplishments

1. Both the MP and SMP run the core (timers, schedulers) TinyOS successfully which the debug tools such as LED’s and buzzers.
2. The radio interfaced with the MP over SPI bus, has been completely ported and the ENS box now is 802.15.4 compatible. The box can now successfully be part of a TelosB network.
3. Master / Slave I2C communication, under TinyOS has been successfully demonstrated between the two microcontrollers. This communication is important part of the porting process as it will enable the multi-processor RPC type calls between the MP and SMP. For the peripherals connected to SMP, the modules directly communicating to these peripherals (under HAL) will be modified to make I2C calls instead. The HAL will hide this I2C abstraction from all the above layers.
4. Presently we are working on porting the SST25VF020 flash to TinyOS on the SMP.

Future Directions

The next effort is to port TinyOS to the LEAP-II platform being built as part of the Low Power Energy Aware Processing project. This platform is very similar to the ENS box with a  high-power processor/high-power radio module and low-power processor/low-power radio module.With the experience gained by porting TinyOS to the ENS box architecture we hope to quickly port the hardware-specific components of TinyOS to work with the LEAP-II platform.

People

Faculty:

• Prof. Gaurav Sukhatme, USC CS Department
• Prof. William Kaiser,      UCLA EE Department

Graduate Students:

• Mansi Shah
• Karthik Dantu