Network Kernel Architectures and Implementation (01204423) - - PowerPoint PPT Presentation
Network Kernel Architectures and Implementation (01204423) Single-Node Architectures Chaiporn Jaikaeo chaiporn.j@ku.ac.th Department of Computer Engineering Kasetsart University Materials taken from lecture slides by Karl and Willig Contiki
Chaiporn Jaikaeo chaiporn.j@ku.ac.th Department of Computer Engineering Kasetsart University
Materials taken from lecture slides by Karl and Willig Contiki materials taken from slides by Adam Dunkels
Communication Device Controller Sensors/ Actuators Power Supply Memory
radio wave bit stream
inflexible
reception
receive ver can already process simple addresses
to stop reflecting
sent back to laser source
200 µm
hygrometer, …
http://en.wikipedia.org/wiki/Energy_density
How to recharge a battery?
Ambient energy sources
a shoe
(MEMS gas turbines)
Pactive Psleep time tevent t1 Esaved tdown tup Eoverhead
up sleep active sleep active down event
1
By Infineon, EU
Comm: Infineon radio modem TDA5250
By Sentilla (formerly Moteiv), USA
MCU:
Comm:
(IEEE 802.15.4)
By Crossbow, USA
Comm: Atmel's RF230 (IEEE 802.15.4)
3x radio range compared to Tmote
"Postage-stamp" form factor costs as low as $29 per unit (when purchased in large volumes)
HopeRF 433 MHz module based on Silicon Labs's SoC (~6 USD/module) Synapse Wireless 2.4 GHz module based on Atmel's SoC SNAP OS / embedded Python (~25 USD/module)
Radio transceiver 8-bit AVR Microcontroller USB Connector (for reprogramming and power) Analog/Digital sensor connectors External battery connector UART Connector Morakot Saravanee, Chaiporn Jaikaeo, 2010. Intelligent Wireless Network Group (IWING), KU
MHz
(virtualization)
hungry
node
efficiency
Poll sensor Process sensor data Poll transceiver Process received packet
anyway
Handle sensor process Handle packet process OS-mediated process switching
Idle/regular processing
Radio event handler Sensor event handler
protection against each other
Software Hardware
#include <motelib/system.h> #include <motelib/timer.h> #include <motelib/radio.h> #include <motelib/led.h> Timer timer; uint8_t counter; void timerFired(Timer *t) { counter++; radioRequestTx(BROADCAST_ADDR, 0, (char*)&counter, sizeof(counter), NULL); } void receive(Address source, MessageType type, void *message, uint8_t len) { ledSetValue(((char*)message)[0]); } void boot() { counter = 0; if (getAddress() == 0) { timerCreate(&timer); timerStart(&timer, TIMER_PERIODIC, 500, timerFired); } else radioSetRxHandler(receive); }
called when node receives a radio packet called when timer expires called when node booted
events
ring them together (akin to VHDL – hardware description language)
Components
program
Hierarchically arranged
from hardware
downward
TimerComponent
setRate fire init start stop fired
Event handlers Command handlers Frame Tasks
Clock
setRate fire init start stop fired
Timer StdCtrl
TimerComponent
Clock
HWClock
Clock Timer StdCtrl
TimerComponent
"Clock" interface provider "Clock" interface user
init
StdCtrl
start stop fired
Timer
configuration CompleteTimer { provides { interface StdCtrl; interface Timer; } implementation { components TimerComponent, HWClock; StdCtrl = TimerComponent.StdCtrl; Timer = TimerComponent.Timer; TimerComponent.Clock -> HWClock.Clock; } }
Active Messages Route map router sensor app
RFM Radio byte Radio Packet UART Serial Packet ADC Temp photo clocks bit byte packet application
HW SW
request to perform some action
Idle / Running task
task queue
Sensor event handler Radio event handler
Request Data Blocking Sensor Controller
Synchronous Operation Asynchronous Operation
Sensor Controller Request Ready Ack Read Data
Thread 1 Thread 2 Thread 3 Thread 4
Eventhandler 1 Eventhandler 2 Eventhandler 3
Eventhandler 4
Threads: sequential code flow Events: unstructured code flow
Events require one stack
Protothread 1 Protothread 2 Protothread 3 Protothread 4