Lab 4 ZigBee

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Lab 4ZigBee 802.15.4 with PICDEM Z Boards

• 55088
• Fall 2006

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Everyone has heard of 802.11 (Wi-Fi)

• IEEE 802.11 features
• Ethernet matching speed,
• Long range(30-90m)
• Complexity to handle seamless roaming
• Message forwarding
• Data throughput of 2-11Mbit/s

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so what is 802.15?

• Specializes in Wireless PAN (Personal Area
  Network) standards
• 802.15.1 a.k.a. Bluetooth(1 Mbps)
• 802.15.2 - Deals with coexistence of Wireless LAN
  (802.11) and Wireless PAN
• 802.15.3 - High-rate WPAN standards (Wireless
  USB)
• 802.15.4 a.k.a ZigBee, low-data rate, low-power
  networks

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What is ZigBee about?

• ZigBee can be found in embedded applications
  requiring low data rates and low power
  consumption
• Fortunately, it is (relatively) low complexity as
  well
• Applications include
• Embedded sensors
• Medical devices
• Smoke and intruder alarms
• Home automation
• PC peripherals

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ZigBee/802.15.4 features

• Transmission range
• 10m 75m
• Three operating bands
• 868 MHz (20kbps) (ch. 0)
• 915 MHz (40kbps) (ch. 1-10)
• 2.4 GHz (250kbps) (ch. 11-26)
• Three types of networks
• Star
• Cluster
• Mesh

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Channel Spacing
In the 2.4GHz band, each channel is about 3MHz
wide
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Types of IEEE 802.15.4 nodes

• Full Function Devices (FFDs)
• Every network needs to have at least one FFD that
  acts as a Coordinator
• FFDs are always powered on
• Maintain the state of the network so that RFDs
  can save battery power
• Require more system resources (memory especially)
  in order to keep track of network state,
  addresses, routes, messages

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Types of IEEE 802.15.4 nodes

• Reduced Function Devices (RFDs)
• Can only talk with FFDs
• Spend most of time powered down, will not receive
  messages when off
• Wake up occasionally and ask to see if they have
  a packet(s) waiting for them from their parent
  node (FFD)

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Types of ZigBee nodes

• Coordinator
• This is an FFD
• Only one per network, is in charge of forming it
• Router
• This is an FFD
• Optional node that extends the range of the
  network
• End
• This is an RFD (usually) the performs monitoring
  and/or control functions

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How does ZigBee form networks?

• Basic Type Star Networks

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How does ZigBee form networks?

• More Complex Cluster Network

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How does ZigBee form networks?

• Very Complex Mesh Networks

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What does this have to do with 55088?

• Lab 4 will be using 802.15.4 radios to create a
  wireless serial link between two nodes
• Each group will be provided with the pair of
  wireless radios on development boards from
  Microchip
• These kits are NOT to be removed from the lab

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PICDEM Z Boards
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CC2420 Radio IC

• 2.4 GHz RF Transceiver
• Connect to microcontrollers via SPI
• Comes on a daughter board with the PICDEM Z kit
• 250 kbps data rate
• 2.1V 3.6V
• 19.7 mA (RX)
• 17.4 mA (TX)

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18LF4620
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18LF4620

• Microcontroller found with the PICDEM Z kits
• Overall, very similar to the 18F452
• Biggest difference that will matter to you is
  that these operate at 3.3V, instead of 5V
• Use the MPLAB and C18 compiler to write code for
  the PIC

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18LF4620 on the PICDEMZ

• Pin 1 Reset Button
• Pin 2-3 LEDs
• Pin 11-12 Power
• Pin 13-14 4 MHz XTL
• Pin 15-18 CC2420
• Pin 23-24 CC2420
• Pin 25-26 USART
• Pin 31-32 Power
• Pin 33-36 CC2420
• Pin 37-38 Interrupt Buttons
• Pin 39-40 ICD 2

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Lab 4 Overview

• A text-input GUI on a computer will connect via
  RS-232 to one of the PICDEM Z boards (well call
  this the Base Station)
• The other PICDEM Z board will be connected to a
  Liquid Crystal Display (LCD) that will display
  the text messages from the base station (well
  call this the Remote Station)

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Lab 4 Overview

• The remote station will have a couple of
  switches which will either indicate an on or
  off state
• The switch states need to be sent back to the
  base station and displayed on the base station GUI

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Example Layout
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PICDEM Z with LCD
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GUI Layout on Base Station

• Use whatever language you wish to create the GUI

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Tools that you will use

• Microchip has developed code that makes
  interfacing with the 802.15.4 radios vastly
  easier
• This is called the stack

Template Your Code
ZigBee
IEEE 802.15.4
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Tools that you will use

• In order to utilize the stack
• MPLAB v 7.41
• C18 Compiler
• Microchip ZigBee stack v 3.5
• ZENA Stack Configuration Tool
• Look at example files
• C\MpZBee\DemoCoordinator\
• C\MpZBee\DemoRFD\
• Do NOT alter files in the Stack directory as this
  could cause the computer (or worse, the TA) to
  explode
• Look, but dont touch

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ZENA
Found in the MpZBee directory
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ZENA
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ZENA
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Profiles and Endpoints

• You will need to select a profile or create your
  own to detail how components interface with one
  another
• A functional block of code that supports a
  component is called an endpoint
• For the lab, best option is to use the
  zHCLighting.h profile provided with the stack and
  make a few changes

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Zigbee.def

• Created by ZENA
• It selects many key parameters that will define
  how a particular node will operate
• Specify Coordinator, Router, or End Device
• Frequencies (channels) to operate on
• Power mode
• Node address
• As well as many other network factors

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zLink.lkr

• Created by ZENA
• Allocates RAM and ROM
• Reserves space on the PIC for the stack (differs
  for RFD and FFD)
• Reserves space on the PIC for received messages
  and messages to be sent
• Dont modify what ZENA generated

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myZigBee.c

• Defines ZigBee network parameters
• ZigBee Device Object Endpoint
• References Zigbee.def to fill out some of the
  parameters
• Suggestion Compare to the myZigBee.c files found
  in the demo programs to help understand how
  endpoints work

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How is a message formatted?
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