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Wireless Sensor Networks (WISeNET) CPU Group

Second Presentation Almir DavisYong Zhang

Halligan Hall 03/03/2005

22

Agenda

Project Description

Sensor Card Diagram

Sensor & Transceiver

CPU Design

CPU Open Issues

Questions from the Preliminary Presentation

Current Questions

33

Project Description

The project’s objective is to design a network of independent sensors that would be able to sense the chemical structure of air’s particles and communicate the findings to the base computing station.

44

WSN Block Diagram

TRANCEIVERCPU

BASE STATIONFIXED LINE NETWORK

WIRELESS SENSOR

NETWORK

SENSOR CARD

TRANCEIVERCPU

SENSOR CARD

TR

AN

CE

IVE

RC

PUS

EN

SO

R C

AR

D

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Sensor Card

TRANCEIVER CPU

SENSOR CARD

TIO SIO

Sensor

I/O to WSN

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Biochemical Sensors:

A device incorporating a biochemical sensing element either intimately connected to or integrated within a transducer.

77

Biochemical Sensors Principles:

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Current Sensors’ Detection Techniques

Surface wave acoustic detection

Ion mobility spectroscopy

Mass spectroscopy

Gas chromatography

Smart dust

99

CPU Block Diagram

CPU

SENSOR 2

SENSOR 1

TRANSCEIVER

ALIVE1

READY1

DATA1

ALIVE2

READY2

DATA2

CLOCK RESET

RX_CTRL[1:0]

DATA_IN

TX_CTRL[1:0]

DATA_OUT

ADDR[2:0] RCV_DATA[8:0]

9

DV

1010

CPU Receive

sleep active sleep

valid

ADDR+DATAADDR+DATApreamblepreamble

value = 010000111

CLOCK

RX_CTRL[1:0]

DATA_OUT

DV

RCV_DATA[8:0]

1111

CPU Transmit (part a)

000111

CLOCK

ALIVE1

READY1

DATA1

READY_I

DATA_I[5:0]

1212

CPU Transmit (part b)

valid

sleep active sleep

010

ADDR+DATAADDR+DATApreamblepreamble

value = 000111

CLOCK

READY_I

DATA_I[5:0]

TX_CTRL[1:0]

DATA_OUT

ADDR[2:0]

1313

WSN CPU Arbitration

011011 011100

receiving 011100receiving 011100

receiving 011011receiving 011011

CLOCK

ALIVE1

ALIVE2

READY1

READY2

DATA1

DATA2

DATA_I[5:0]

READY_I

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Open Issues

Shared sensor data bus

Clock frequency

“Active”, “Sleep” duty cycles

Internal CPU registers programmable wirelessly

In-Band Hot reset

Preamble size

Piggy-backed multi-sensor packets

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Questions from the Preliminary Presentation Can you put the CPU to sleep as well as the transceiver?

– Transceiver can be put to sleep. CPU cannot.

In transceiver design you might want to separate RX & TX paths with different antennas to avoid collision.

– Good observation. We will have separate control/data paths for the RX and TX side (reflected in the CPU design)

For power efficiency: A lot has to do with MOSFET scaling, voltage level, logic style, I/O pins. Will you address these issues?

– We address the issue by reducing the number of IO pins, reducing the internal CPU memory size, and reducing the gate count by reducing the number of features. We will also address the issue of MOSFET scaling by choosing the vendor with a power efficient chip technology.

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Questions from the Preliminary Presentation Ambitious project, well thought through out, but will the

end-product work?

Warning! If everyone communicates to the base station it may lead to congestion, dropped messages etc… Need to clarify this transfer of data early on.

– Na Wang, PH.D. student and the member of Professor’s Chang project team is assigned to deal with network related issues including the congestion issues.

Automatic power optimization after behavioral HDL code.

– Good point. We do it at the RTL level but would appreciate your help if we are doing something wrong.

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Questions from the Preliminary Presentation

How are you going to test the CPU before you build the CPU?

– We will present the portion of the test right now …

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