TinyOS and nesC
Lesson 1
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Distributed Embedded Software and Networks
TDDI07#
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Ekhiotz Vergara
12/11/15
Summary
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Lab environment and rules
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TinyOS
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"
Goals
"
Features
"
Operation
nesC
"
Features supporting TinyOS
"
Keywords
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Component example
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Real interface example
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TinyOS Application example
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Lab environment
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Work in pairs
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Real sensor nodes
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Unscheduled time
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Lab preparation
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Report
Scheduled time
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Work in the labs with the sensor nodes
Deadlines
2
Lab rules
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Use of real hardware:
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Sensor nodes only available during lab hours
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You are responsible for the sensor nodes and USB cables
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You are required to demonstrate the labs running in the
nodes during lab hours
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You are required to prepare for the labs in advance to be
able to finish before the deadline
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Plagiarism cases will be reported
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Report template for each lab
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Labs
LESSON 2
LESSON 1
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Lab 1: PhotoMeter
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Illuminance measurement and display
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Lab 2: Traffic Light
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Lab 3: Energy efficient wireless communication
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Wireless communication
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Energy consumption
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Summary
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Lab environment and rules
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TinyOS
!
"
Goals
"
Features
"
Operation
nesC
"
Features supporting TinyOS
"
Keywords
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Component example
!
Real interface example
!
TinyOS Application example
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Sensing applications
Bridge vibration monitoring
Monitoring the microclimate
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Underwater sensing
Body sensor 6networks
Building monitoring
TinyOS Goals
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Hardware abstraction
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Limited resources
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Low cost and small devices
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Low power operation
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Flexibility
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Hardware
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Applications
TinyOS
Min. size
400 bytes!
Efficient processing
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TinyOS Platform example
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Resource constrained device
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Low power consumption
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MSP430 microcontroller
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8 MHz 16 bit RISC
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10kB RAM
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1 MB external flash
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250 kbps low power radio
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AA Batteries
TinyOS Features
10 KB
Stack
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Concurrency model: Reactive
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!
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Global
0 KB
Single stack
Applications are composed by components
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Sequential and event-driven processing
Simple memory model
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Modularity provided by components used as building blocks
Specialized operating system integrated with applications
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Application is built with the components that compose the
operating system
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Free
TinyOS is a “library”
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TinyOS Components
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Provide operating system abstraction layers
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Encapsulate set of services or functionalities
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Interfaces are bidirectional
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Interfaces
Use or provide a functionality
Modules implement components
Interface
Module X
Component X
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TinyOS Components - Wiring
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Applications created wiring components
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Reusability of components
Main component is application starting point
Component App
App Module
Interface
Interface
Module X
Component X
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TinyOS Operation
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Event-driven nature
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Asynchronous hardware interrupts (timer, radio, sensor…)
Synchronous sequential tasks
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Run to completion – keep tasks short!
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Standard scheduler FIFO policy
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Tasks are atomic to other tasks, but not to interrupt handlers
or commands and events they invoke
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Split-phase operation
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Commands
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Events
Interface A
Interface B
Module
Interface C
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TinyOS Operation example
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Asynchronous code
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Timer interruption (TI)
post a task that switches LEDs on/off according to a shared variable X
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Synchronous code (tasks)
TI LEDs
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Switch on/off the LEDs (LEDs)
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Heavy computation
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Update the shared variable X (U)
TI LEDs
Computation
Delayed hardware
interrupt!
Responsiveness
U TI LEDs U
Time
TI LEDs
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Computation
TI LEDs
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U TI LEDs
atomic
Time
Summary
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Lab environment and rules
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TinyOS
!
"
Goals
"
Features
"
Operation
nesC
"
Features supporting TinyOS
"
Keywords
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Component example
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Real interface example
!
TinyOS Application example
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nesC – Language support
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nesC: network embedded system C
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TinyOS written in nesC
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Component-based
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Similar to objects
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Discrete unit of functionality
Local namespace
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Implementing functions
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Declare functions that it calls
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nesC Keywords
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Includes
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Interface
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Module, configuration
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provide, uses, as
Implementation
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components
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Task – post
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Event – signal
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Command – call
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Atomic
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Configuration - Wiring
Component App
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Connect interfaces
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User -> provider
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Provider <- user
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Provider = provider
Interface X
Interface X
Module X
Component X
Interpretation of arrows:
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App Module
-> : Get functionality of this interface from this component
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ApplicationC.InterfaceX -> ComponentX;
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ApplicationC.InterfaceX -> ComponentX.InterfaceX;
= : forward the functionality from this component
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Summary
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Lab environment and rules
!
TinyOS
!
"
Goals
"
Features
"
Operation
nesC
"
Features supporting TinyOS
"
Keywords
!
Component example
!
Real interface example
!
TinyOS Application example
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Component example (1)
Status
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Provided Interfaces
Control
Baker
interface Status {
command uint32_t timeLeft();
command void setTime(uint32_t time);
}
interface Control {
command void startBaking(uint32_t cakeType);
event void cakeReady();
}
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Commands called by user and implemented by provider
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call
Events implemented by user and signalled by provider
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Oven
signal
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Component example (2)
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Used interface
interface Oven {
command void setTemperature(uint32_t temp);
event void temperatureReady();
}
Status
Control
Baker
Oven
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Component example (3)
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Implementation
module Baker {
provides
{
interface Control;
interface Status;
}
uses interface Oven;
}
implementation {
event void Oven.temperatureReady()
{
// do some stuff
}
}
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Status
Control
Baker
Oven
Component example (4)
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Status
Configuration
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Wiring
Status
configuration BakerC {
provides {
interface Control;
interface Status;
}
}
implementation {
components OvenC;
BakerC.Oven -> OvenC;
}
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Control
Control
Baker
Oven
Oven
OvenC
BakerC
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Summary
!
Lab environment and rules
!
TinyOS
!
"
Goals
"
Features
"
Operation
nesC
"
Features supporting TinyOS
"
Keywords
!
Component example
!
Real interface example
!
TinyOS Application example
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Real interface example
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Timer interface
interface Timer
{
command void startPeriodic (uint32_t dt);
command void startOneShot(uint32_t dt);
command uint32_t getNow();
event void fired();
…
}
…..
Timer
… = It has more commands and events
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Real application example
BlinkAppC.nc
BlinkAppC.nc
module BlinkC {
uses interface Timer<TMilli> as Timer0;
uses interface Timer<TMilli> as Timer1;
uses interface Leds;
uses interface Boot;
}
implementation
{
event void Boot.booted()
{
call Timer0.startPeriodic( 250 );
configuration BlinkAppC
{
}
implementation
{
components MainC, BlinkC, LedsC;
components new TimerMilliC() as Timer0;
components new TimerMilliC() as Timer1;
BlinkC -> MainC.Boot;
call Timer1.startPeriodic( 500 );
BlinkC.Timer0 -> Timer0;
BlinkC.Timer1 -> Timer1;
BlinkC.Leds -> LedsC;
}
event void Timer0.fired()
{
call Leds.led0Toggle();
}
}
How many different interfaces?
How many components?
How does the application start?
How many commands are used?
What is the flow of the application?
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event void Timer1.fired()
{
call Leds.led1Toggle();
}
}
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Application exercise
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Draw the diagram
Interface
Command
Component
Event
BlinkC
Boot
booted&
Timer0
Timer1
startPeriodic&
startPeriodic&
fired&
fired&
led0Toggle&
led1Toggle&
Boot
Timer0
Timer1
Leds
MainC
TimerMilliC
(Timer0)
TimerMilliC
(Timer1)
LedsC
BlinkAppC
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Leds
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TinyOS Directory
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TOSSIM
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TinyOS Simulator
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Python interface
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Simulate nodes using debug messages
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Same code of real hardware
http://docs.tinyos.net/tinywiki/index.php/TOSSIM#Compiling_TOSSIM
>>> m.isOn()
1
>>> m.turnOff()
>>> m.isOn()
0
>>> m.bootAtTime(560000)
>>> t.runNextEvent()
DEBUG (32): Application booted.
1
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AVRORA
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Simulator to test the programs
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Cycle accurate execution of AVR microcontrollers
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Same code of real hardware
http://avrora.cvs.sourceforge.net/avrora/
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References
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TinyOS: An operating system for sensor networks
P. Levis, S. Madden, J. Polastre, R. Szewczyk, K. Whitehouse, A. Woo, D. Gay, J. Hill,
M. Welsh, E. Brewer, and D. Culler. TinyOS: An operating system for sensor networks ambient
intelligence. In Werner Weber, Jan M. Rabaey, and Emile Aarts, editors, Ambient Intelligence,
chapter 7, pages 115–148. Springer Berlin Heidelberg, Berlin/Heidelberg, 2005.
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TinyOS programming
http://www.tinyos.net/tinyos-2.x/doc/pdf/tinyos-programming.pdf
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TinyOS website
http://www.tinyos.net
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Datasheet of TelosB sensor node
http://www.willow.co.uk/TelosB_Datasheet.pdf
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