Peek into TinyOS Programs

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Peek into TinyOS Programs

• Vinod Kulathumani

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Basics

• Application consists of one or more components
  assembled, or wired
• A component provides and uses interfaces.
• Interfaces are bidirectional
• they specify a set of commands
• and a set of events
• For a component to call the commands in an
  interface, it must implement the events of that
  interface.
• A single component may use or provide multiple
  interfaces and multiple instances of the same
  interface.
• Signature - The set of interfaces a component
  provides set of interfaces that a component uses

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Components

• Two types of components in nesC
• modules and configurations
• Modules provide the implementations of one or
  more interfaces
• Configurations are used to assemble other
  components together
• connect interfaces used by components to
  interfaces provided by others
• Every nesC application described by a top-level
  configuration

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Convention

• Header File abc.h
• Interface abc.nc
• Configuration abcAppC.nc
• Module Public abcC.nc
• Module Private abcP.nc

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HelloAppC Configuration

• configuration HelloAppC
• implementation

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HelloAppC Configuration

• configuration HelloAppC
• implementation
• components HelloC

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HelloC Module

• module HelloC
• implementation

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HelloC Module

• module HelloC
• uses
• interface Boot
• interface Leds
• implementation

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HelloC Module

• module HelloC
• uses
• interface Boot
• interface Leds
• implementation

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Boot Interface

• interface Boot
• event void booted()

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HelloC Module

• module HelloC
• uses
• interface Boot
• interface Leds
• implementation
• event void Boot.booted()

USE an interface, CAPTURE all of its events!
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Leds Interface

• interface Leds
• command void led0On()
• command void led0Off()
• command void led0Toggle()
• command void set(uint8_t val)

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HelloC Module

• module HelloC
• uses
• interface Boot
• interface Leds
• implementation
• event void Boot.booted()
• call Leds.led0On()

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HelloAppC Configuration

• configuration HelloAppC
• implementation
• components HelloC,
• MainC,
• LedsC
• // USES -gt PROVIDES
• HelloC.Boot -gt MainC.Boot
• HelloC.Leds -gt LedsC

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Hello Application
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Example 2 Blink

• Configuration BlinkAppC.nc
• Module BlinkC.nc

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Configuration

• configuration BlinkAppC
• implementation

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Implementation

• module BlinkC
• implementation

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Configuration components list

• configuration BlinkAppC
• implementation
• components MainC, BlinkC, LedsC
• components new TimerMilliC() as Timer0
• components new TimerMilliC() as Timer1
• components new TimerMilliC() as Timer2

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Module provides / uses

• Module BlinkC
• uses interface TimerltTMilligt as Timer0
• uses interface TimerltTMilligt as Timer1
• uses interface TimerltTMilligt as Timer2
• uses interface Leds
• uses interface Boot
• implementation
• // implementation code omitted

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Module provides / uses

• Module BlinkC
• uses interface TimerltTMilligt as Timer0
• uses interface TimerltTMilligt as Timer1
• uses interface TimerltTMilligt as Timer2
• uses interface Leds
• uses interface Boot
• implementation
• event void Boot.booted() call
  Timer0.start() .
• event Timer0.fired()
• event Timer1.fired()

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Configuration wiring

• configuration BlinkAppC
• implementation
• components MainC, BlinkC, LedsC
• components new TimerMilliC() as Timer0
• components new TimerMilliC() as Timer1
• components new TimerMilliC() as Timer2
• BlinkC.Boot -gt MainC.Boot
• BlinkC.Timer0 -gt Timer0
• BlinkC.Timer1 -gt Timer1
• BlinkC.Timer2 -gt Timer2
• BlinkC.Leds -gt LedsC

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Radio Stacks
Your Application
SplitControl
Receive
AMSend
Message Queue
ActiveMessage
CSMA / Acknowledgements
Transmit / Receive / Init
Radio Hardware
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Main Radio Interfaces

• SplitControl
• Provided by ActiveMessageC
• AMSend
• Provided by AMSenderC
• Receive
• Provided by AMReceiverC

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Main Serial Interfaces

• SplitControl
• Provided by SerialActiveMessageC
• AMSend
• Provided by SerialAMSenderC
• Receive
• Provided by SerialAMReceiverC

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Setting up the Radio Configuration

• configuration MyRadioAppC
• implementation
• components MyRadioC,
• MainC,
• ActiveMessageC,
• new AMSenderC(0) as Send0, // send an AM type
  0 message
• new AMReceiverC(0) as Receive0 // receive an
  AM type 0

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Setting up the Radio Module

• module MyRadioC
• uses
• interface Boot
• interface SplitControl
• interface AMSend
• interface Receive
• implementation

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Turn on the Radio

• event void Boot.booted()
• call SplitControl.start()
• event void SplitControl.startDone(error_t
  error)
• post sendMsg()
• event void SplitControl.stopDone(error_t error)
  

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Setting up the Radio Configuration

• configuration MyRadioAppC
• implementation
• components MyRadioC,
• MainC,
• ActiveMessageC,
• new AMSenderC(0) as Send0, // send an AM type
  0 message
• new AMReceiverC(0) as Receive0 // receive an
  AM type 0
• MyRadioC.Boot -gt MainC
• MyRadioC.SplitControl -gt ActiveMessageC
• MyRadioC.AMSend -gt Send0
• MyRadioC.Receiver -gt Receive0

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Payloads

• A message consists of
• Header
• Payload
• Optional Footer

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message_t

• typedef nx_struct message_t
• nx_uint8_t headersizeof(message_header_t)
• nx_uint8_t dataTOSH_DATA_LENGTH
• nx_uint8_t footersizeof(message_footer_t)
• nx_uint8_t metadatasizeof(message_metadata_t)
• message_t

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Payloads Use Network Types

• (MyPayload.h)
• typedef nx_struct MyPayload
• nx_uint8_t count
• MyPayload

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Send Messages

• message_t myMsg
• bool sendingfalse
• task void sendMsg()
• MyPayload payload (MyPayload )call
  ASMSend.getPayload(myMsg)
• payload-gtcount (myCount)
• if (sendingfalse)
• error_t p
• p call AMSend.send(AM_BROADCAST_ADDR,
  myMsg, 0)
• If (pSUCCESS) sendingtrue
• else post sendMsg()
• event void AMSend.sendDone(message_t msg,
• error_t error)
• sendingfalse

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Receive a Message

• event message_t Receive.receive(message_t msg,
  void
• payload, uint8_t length)
• MyPayload pkt (MyPayload )payload
• uint8_t ct pkt-gtcount
• call Leds.led0Toggle()
• return msg

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RealMainP

• module RealMainP
• provides interface Boot
• uses
• interface Scheduler
• interface Init as PlatformInit
• interface Init as SoftwareInit
• Implementation
• // platform initialization stuff
• call SoftwareInit.init()
• signal Boot.booted()
• // call scheduler task loop

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SoftwareInit in RealMainP

• Suppose user writes module RandomIntC
• provides an interface Init
• should be initialized before use (to generate
  seed)
• what if application developer forgets
• Instead write a configuration RandomC around
  RandomIntC
• Module RandomC
• provides interface Init
• Implementation RandomC
• components MainC, RandomIntC
• MainC.SoftwareInit -gt RandomIntc.Init

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SoftwareInit in RealMainP

• So far we didnt care in our examples
• All our examples were applications
• Did not provide interface
• Interior components that provide interface may
  need Init
• MainC.SoftwareInit may be wired to many Inits
• Each will be called in sequence

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References

• TinyOS Tutorials www.tinyos.net
• David Moss TinyOS 2 tutorial