Lab4

1. Lab4 Objectives Learn to read light sensor data from sensor board Learn to transmit a message containing the sensed data through Mote serial port (UART) connected directly to the programming board

2. Required Hardware and PC Setup • Two MICA Motes: standard editions of MICA2 (MPR4x0) or MICAz (MPR2600) • One sensor or data acquisition board: MDA100, MTS300 or MTS310 • One gateway board: MIB510, MIB520, or MIB600 and the associated hardware (cables, power supply) for each • A Windows PC with MoteWorks installed

3. MyApp Application Review • Under the directory /MoteWorks/apps/tutorials/lesson_ 2 • The Makefile and Makefile.component are exactly the same as the MyApp of lesson_1.

4. About MyApp • What does MyApp do? • a simple sensing application that samples the light sensor (photodetector) on a sensor board, packetizes the data, and sends the data back to the base station. • How does it differ from the application in lesson_1 ? • Take light readings using sensors boards • Use the Mote serial port (UART) to send sensor data to the base station • Blink the green LED when the sensor is sampled • Blink the yellow LED when the sensor data message is successfully sent to the base station

5. Sensor Application MyApp_Sensor • What’s new? • The sensorboardsApp.h file • What is it used for? • Define packet structure • Defines the XSensor header • Defines the sensor data payload • So you can understand what the bytes mean in a serial data stream • Defines the default values for critical fields • SENSOR_BOARD_ID • “Tags” the packet so XServe can identify what application sent it • Sensor data packets are put into the proper database table or flat file by XServe

6. MyApp Steps Makefile Makefile.component Top-level application configuration Top-level module Compile app and flash Motes nesC Auto documentation

7. MyApp – Makefile.component • Specify the sensorboard in the Makefile.component file • For example, the Makefile.component for MyApp is • What does this do? • Tells the nesC compiler to link in all the TinyOS components (drivers) required to access the sensors on the MTS310 sensorboard. • Drivers for the MTS310 sensorboard are located in the /MoteWorks/tos/sensorboards/mts310 folder. • NOTE: There are drivers for other sensorboards located in under /MoteWorks/tos/sensorboards. COMPONENT=MyApp SENSORBOARD=mts310 Note: we’ll need to use SENSORBOARD=mda100cb

8. Review: MyApp Steps Makefile Makefile.component Top-level application configuration Top-level module Compile app and flash Motes nesC Auto documentation

9. /MoteWorks/apps/tutorials/lesson_2/MyApp.nc Configuration – Sampling the Light Sensor Include a header file • includes sensorboardApp; • /** • * This module shows how to use the Timer, LED, ADC and Messaging • * components. • * Sensor messages are sent to the serial port • **/ • configuration MyApp { • } • implementation { • components Main, MyAppM, TimerC, LedsC, Photo, GenericComm as Comm; • Main.StdControl -> TimerC.StdControl; • Main.StdControl -> MyAppM.StdControl; • Main.StdControl -> Comm.Control; • MyAppM.Timer -> TimerC.Timer[unique("Timer")]; • MyAppM.Leds -> LedsC.Leds; • MyAppM.PhotoControl -> Photo.PhotoStdControl; • MyAppM.Light -> Photo.ExternalPhotoADC; • MyAppM.SendMsg -> Comm.SendMsg[AM_XSXMSG]; • } NEW! The Photo component is used to actuate the sensorboard photo sensor device. NEW! TheGenericComm component is used to send messages over the serial port or radio.

10. MyApp.nc Configuration – Sampling the Light Sensor • includes sensorboardApp; • /** • * This module shows how to use the Timer, LED, ADC and Messaging • * components. • * Sensor messages are sent to the serial port • **/ • configuration MyApp { • } • implementation { • components Main, MyAppM, TimerC, LedsC, Photo, GenericComm as Comm; • Main.StdControl -> TimerC.StdControl; • Main.StdControl -> MyAppM.StdControl; • Main.StdControl -> Comm.Control; • MyAppM.Timer -> TimerC.Timer[unique("Timer")]; • MyAppM.Leds -> LedsC.Leds; • MyAppM.PhotoControl -> Photo.PhotoStdControl; • MyAppM.Light -> Photo.ExternalPhotoADC; • MyAppM.SendMsg -> Comm.SendMsg[AM_XSXMSG]; • } The Photo component implements the StdControl interface for turning on and off the light sensor and the ADC interface for sampling the sensor value through the hardware ADC port.

11. MyApp.nc Configuration – Sampling the Light Sensor • includes sensorboardApp; • /** • * This module shows how to use the Timer, LED, ADC and Messaging • * components. • * Sensor messages are sent to the serial port • **/ • configuration MyApp { • } • implementation { • components Main, MyAppM, TimerC, LedsC, Photo, GenericComm as Comm; • Main.StdControl -> TimerC.StdControl; • Main.StdControl -> MyAppM.StdControl; • Main.StdControl -> Comm.Control; • MyAppM.Timer -> TimerC.Timer[unique("Timer")]; • MyAppM.Leds -> LedsC.Leds; • MyAppM.PhotoControl -> Photo.PhotoStdControl; • MyAppM.Light -> Photo.ExternalPhotoADC; • MyAppM.SendMsg -> Comm.SendMsg[AM_XSXMSG]; • } • MyAppM.PhotoControl (StdControl interface) to the Photo.PhotoStdControl (StdControl interface for the light sensor) • The MyAppM.Light (ADC interface) to the • Photo.ExternalPhotoADC (ADC interface for light sensor).

12. MyApp.nc Configuration – Sampling the Light Sensor • includes sensorboardApp; • /** • * This module shows how to use the Timer, LED, ADC and Messaging • * components. • * Sensor messages are sent to the serial port • **/ • configuration MyApp { • } • implementation { • components Main, MyAppM, TimerC, LedsC, Photo, GenericComm as Comm; • Main.StdControl -> TimerC.StdControl; • Main.StdControl -> MyAppM.StdControl; • Main.StdControl -> Comm.Control; • MyAppM.Timer -> TimerC.Timer[unique("Timer")]; • MyAppM.Leds -> LedsC.Leds; • MyAppM.PhotoControl -> Photo.PhotoStdControl; • MyAppM.Light -> Photo.ExternalPhotoADC; • MyAppM.SendMsg -> Comm.SendMsg[AM_XSXMSG]; • } • This wires the XSensor channel of GenericComm into the application’s send interface.

13. Review: MyApp Steps Makefile Makefile.component Top-level application configuration Top-level module Compile app and flash Motes nesC Auto documentation

14. Top Level Module • Located in MoteWorks/apps/tutorials/lesson_2/MyAppM.nc • How does this module differ from MoteWorks/apps/tutorials/lesson_1/MyAppM.nc? • It adds the functionality of sampling the light sensor when the timer fires • Then a sensor message is sent through the Mote’s serial (UART) port when the sampling is complete.

15. nesC Keywords – Implementation

16. MyAppM.nc – Specification • Hardware specific definitions for the MTS300/310. • Located in the application directory • includes sensorboardApp; • /** • * This module shows how to use the Timer, LED, ADC and Messaging • * components • * Sensor messages are sent to the serial port • **/ • module MyAppM { • provides { • interface StdControl; • } • uses { • interface Timer; • interface Leds; • interface StdControl as PhotoControl; • interface ADC as Light; • interface SendMsg; • } • }

17. MyAppM.nc – Implementation • implementation { • bool sending_packet = FALSE; • TOS_Msg msg_buffer; • XDataMsg *pack; • /** • * Initialize the component. • * • * @return Always returns <code>SUCCESS</code> • **/ • command result_t StdControl.init() { • call Leds.init(); • call PhotoControl.init(); • // Initialize the message packet with default values • atomic { • pack = (XDataMsg *)&(msg_buffer.data); • pack->xSensorHeader.board_id = SENSOR_BOARD_ID; • pack->xSensorHeader.packet_id = 2; • pack->xSensorHeader.node_id = TOS_LOCAL_ADDRESS; • pack->xSensorHeader.rsvd = 0; • } • returnSUCCESS; • }

18. nesC Keywords – Implementation

19. atomic Keyword (Review) • atomickeyword is used to denote a block of code that runs uninterrupted (interrupts disabled) • Prevents race conditions • When should it be used? • Required to update global variables that are referenced in async event handlers • Must use atomic block in all other functions and tasks where variable is referenced • nesC compiler will generate warning messages for global variables that need atomic blocks • Example: SensorAppM.nc:44: warning: non-atomic accesses to shared variable ‘voltage’

20. interface ADC { async command result_t getData(); async command result_t getContinuousData(); async event result_t dataReady(uint16_t data); } The ADC interface is specified with two commands: getData getContinuousData and one event dataReady What to do to sample the sensor? call the getData command This will start a process of sampling the light sensor through the processor hardware ADC interface At some later time this process will complete and receive the current light sensor value through the dataReady event nesC Interface -- ADC

21. event result_t Timer.fired() { call Leds.redToggle(); call PhotoControl.start(); call Light.getData(); … } async event result_t Light.dataReady(uint16_t data) { atomic pack->xData.datap1.light = data; atomic pack->xData.datap1.vref = 417; // a dummy 3V reference voltage, 1252352/3000 = 417 post SendData(); call Leds.yellowToggle(); …} In Timer.fired() event function, we first turn on the light sensor by calling the start() command through the StdControl interface. The red LED will blink (“heartbeat”) when this happens. Next we call the getData() command through the ADC interface to start the process of sampling the current value. At some time in the near future when the sampling has completed, we receive a callback in the form of a dataReady() event. Sample Sensor and Call Back with Value 1 2 3

22. event result_t Timer.fired() { call Leds.redToggle(); call PhotoControl.start(); call Light.getData(); … } async event result_t Light.dataReady(uint16_t data) { atomic pack->xData.datap1.light = data; atomic pack->xData.datap1.vref = 417; // a dummy 3V reference voltage, 1252352/3000 = 417 post SendData(); call Leds.yellowToggle(); …} The dataReady() event passes the 16-bit (10 significant bits) photodetector value that we store in our message packet. The last thing we do is to post a task (a split-phase operation) to send a message containing the sensor data and fire the yellow LED Sample Sensor and Call Back with Value 5 4

23. nesC Keywords – Implementation

24. Non-blocking commands initiate an operation Continue/idle Event indicates completion at some future time Split-Phase -- Request & Done Sequence Component1 Component2 commandA { … call Comp2.goCmdX; //continue return SUCCESS} goCmdX{ … post task1(); return SUCCESS} Task1{ //do stuff signal cmdXDone(); return SUCCESS} Event handler event cmdXDone{ //process result … return SUCCESS} TOS Scheduler

25. When to Use Split-Phase • Variable duration processes • Hardware I/O operations • e.g., ADC start conversion –> Data Ready • Slow devices • e.g., Flash memory, Write buffer –> Done • Asynchronous or Complex Processes • Send a message to communications stack and continue with operations until sendDone

26. Sending a Message Packet – GenericComm • How to send a packet of data to the outside world? • Use the TinyOS communication component named GenericComm. • GenericComm is able to send packets in two ways • The UART port or • Over the radio • How is that specified? • Through destination node address • Reserved node addresses • Broadcast 0xFFFF • UART Channel 0x007E • Otherwise send directly to a specific node ID in it’s RF neighborhood

27. implementation { components Main, MyAppM, TimerC, LedsC, Photo, GenericComm as Comm; Main.StdControl -> TimerC.StdControl; Main.StdControl -> MyAppM.StdControl; Main.StdControl -> Comm.Control; … MyAppM.SendMsg -> Comm.SendMsg[AM_XSXMSG]; … The GenericComm (aliased as Comm) is connected through its Comm.Control (StdControl) interface The MyAppM module connects to one instance of the Comm.SendMsg interface. The AM_XSXMSG identifies the active message type. It is used to distinguish between multiple messages you may wish to send. MoteWorks/apps/tutorials/lesson_2/MyApp.nc Configuration Revisited

28. interface SendMsg { command result_t send(uint16_t address, uint8_t length, TOS_MsgPtr msg); event result_t sendDone(TOS_MsgPtr msg, result_t success); } The SendMsg interface specifies one command Send and one event sendDone To send a message call the send command with the correct parameters A sendDone event is received after the message has been sent nesC Interface -- SendMsg

29. interface SendMsg { command result_t send(uint16_t address, uint8_t length, TOS_MsgPtr msg); event result_t sendDone(TOS_MsgPtr msg, result_t success); } Each message that is sent using the SendMsg interface is defined by a data structure named TOS_Msg nesC Interface -- SendMsg

30. typedef struct TOS_Msg { /* The following fields are transmitted/received on the radio. */ uint16_t addr; uint8_t type; uint8_t group; uint8_t length; int8_t data[TOSH_DATA_LENGTH]; } typedef TOS_Msg *TOS_MsgPtr; addr – the destination address type – the active message type (for this application it is AM_XSXMSG) group – group id specified during programming length – the payload length data – variable length payload area (sensor data) nesC Data Structure -- TOSMsg

31. command result_t StdControl.init() { … // Initialize the message packet with default values atomic { pack = (XDataMsg *)&(msg_buffer.data); pack->xSensorHeader.board_id = SENSOR_BOARD_ID; pack->xSensorHeader.node_id = TOS_LOCAL_ADDRESS; pack->xSensorHeader.rsvd = 0; } … The data region in the TOS_Msg is where we place our application specific payload. The code excerpt above is from the MoteWorks/apps/tutorials/lesson_2/MyAppM.nc module that shows how we initialize the payload area of the TOS_Msg for our specific sensor application MoteWorks/apps/tutorials/lesson_2/MyAppM.nc – Application Data Payload

32. void task SendData() { call PhotoControl.stop(); if (sending_packet) return; atomic sending_packet = TRUE; // send message to UART (serial) port if (call SendMsg.send(TOS_UART_ADDR,sizeof(XDataMsg),&msg_buffer) != SUCCESS) sending_packet = FALSE; …} event result_t SendMsg.sendDone(TOS_MsgPtr msg, result_t success) { call Leds.greenToggle(); atomic sending_packet = FALSE; …} MoteWorks/apps/tutorials/lesson_2/MyAppM.nc – Application Data Payload Notice first how the sendData task calls the stop command for the light sensor component. This is done in order to save power when we are not using the sensor. If we are currently in the process of sending a message (sending_packet = TRUE), we just return. This means the sendDone event has yet to be called and we must wait.

33. void task SendData() { call PhotoControl.stop(); if (sending_packet) return; atomic sending_packet = TRUE; // send message to UART (serial) port if (call SendMsg.send(TOS_UART_ADDR,sizeof(XDataMsg),&msg_buffer) != SUCCESS) sending_packet = FALSE; … event result_t SendMsg.sendDone(TOS_MsgPtr msg, result_t success) { call Leds.greenToggle(); atomic sending_packet = FALSE; … MoteWorks/apps/tutorials/lesson_2/MyAppM.nc – Application Data Payload We call the SendMsg.send command passing the destination node address, in this case TOS_UART_ADDR and a pointer to the actual message packet we wish to send.

34. void task SendData() { call PhotoControl.stop(); if (sending_packet) return; atomic sending_packet = TRUE; // send message to UART (serial) port if (call SendMsg.send(TOS_UART_ADDR,sizeof(XDataMsg),&msg_buffer) != SUCCESS) sending_packet = FALSE; …} event result_t SendMsg.sendDone(TOS_MsgPtr msg, result_t success) { call Leds.greenToggle(); atomic sending_packet = FALSE; …} MoteWorks/apps/tutorials/lesson_2/MyAppM.nc – Application Data Payload Finally the SendMsg.sendDone event is called notifying us the packet has been sent. We are now ready to start the whole process over again the next time the timer fires.

35. Review: MyApp Steps Makefile Makefile.component Top-level application configuration Top-level module Compile app and flash Motes nesC Auto documentation lab

36. MyApp – Compile and Install Program • Compile the MyApp sensor application • Install program to (“flash”) a mote • Watch the LED pattern. What is happening? • You should see the red, green and yellow LED’s blinking every second.

37. nesC Auto documentation • Follow steps stated in Lab 1

38. What you need to do? • Finish Lab4 (posted in HuskyCT)