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(01204423) Sensor Node Programming II (UART and Radio) Chaiporn - PowerPoint PPT Presentation

Dec 17, 2023 •212 likes •410 views

Network Kernel Architectures and Implementation (01204423) Sensor Node Programming II (UART and Radio) Chaiporn Jaikaeo chaiporn.j@ku.ac.th Department of Computer Engineering Kasetsart University Outline UART communication Single-hop

  1. Network Kernel Architectures and Implementation (01204423) Sensor Node Programming II (UART and Radio) Chaiporn Jaikaeo chaiporn.j@ku.ac.th Department of Computer Engineering Kasetsart University

  2. Outline UART communication  Single-hop radio communication  2

  3. Connecting Mote to PC USB connector on IWING-MRF and IWING-JN  3.3V RX TX GND USB dongles  3.3V 5V RX TX GND USB Dongle based on Silicon Labs’s CP2102 ThaiEasyElec’s USB Dongle (FDTI) 3

  4. UA UART RT API ( motelib/uart.h ) Enable UART (both TX and RX)  uartEnable(true,true); Send a single byte over UART  uartWriteByte(50); Send multiple bytes over UART  uint8_t buf[10]; : uartWrite(buf, 10); 4

  5. UART API (cont'd) Check whether there is any data received  from UART if (uartInputLen() > 0) ... Read a single byte from UART input buffer  uint8_t byte = uartReadByte(); Send formatted string over UART using  Standard I/O library #include <stdio.h> : : printf("Hello, world\n"); printf("i = %d\n", i); 5

  6. Processing UART Data on PC Locate UART device file  Run dmesg to find out  Usually /dev/ttyUSB0 or /dev/ttyACM0  $ dmesg : [70063.712091] usb 4-1: new low speed USB device using uhci_hcd and .. [70063.871042] usb 4-1: config 1 interface 1 altsetting .. [70063.871056] usb 4-1: config 1 interface 1 altsetting .. [70063.895220] cdc_acm 4-1:1.0: ttyACM0: USB ACM device For textual data  Run terminal program such as screen ,  gtk-term , putty on UART device For binary data  Any UART library can be used  E.g., Python's serial package  6

  7. USB-UART Implementation MoteLib provides UART-via-USB  implementation for IWING-MRF platform (>= rev. 388)  Emulated using V-USB library by Objective Development  Based on AVR-CDC project (http://www.recursion.jp/avrcdc/) Requires no USB dongle  Build your app with UART_VIA_USB=1  $ make UART_VIA_USB=1 ... 7

  8. Example: sense-to-uart.c Sense light intensity every second; send  values to display via UART void senseDone( uint16_t value) #include <stdio.h> { #include <motelib/system.h> printf("Light = %d\r\n", value); #include <motelib/timer.h> actorSetState(ACTOR_0, 0); #include <motelib/uart.h> } #include <motelib/sensor.h> #include <motelib/actor.h> void sense(Timer *t) { Timer t; actorSetState(ACTOR_0, 1); void senseDone( uint16_t value); sensorRequestAnalog(SENSOR_1, senseDone); void sense(Timer *t); } void boot() { uartEnable(true,true); timerCreate(&t); timerStart(&t, TIMER_PERIODIC, 1000, sense); } 8

  9. Testing sense-to-uart Build with UART_VIA_USB option  $ make UART_VIA_USB=1 flash Capture UART output using screen  (or gtk-term or putty) $ screen /dev/ttyACM0 9

  10. Radio Communication IWING-MRF: Microchip's MRF24J40 controller  IWING-JN: Built-in  IEEE 802.15.4 @ 2.4 GHz, 250 kbps  16 non-overlapping channels  16-bit node ID  16-bit PAN (Personal Area Network) ID  10

  11. Configuring Radio (IWING-MRF) Use config-mote.py script located in  $MOTELIB_DIR/platforms/iwing- mrf/tools Have mote enter bootloader, then run:  $ cd $MOTELIB_DIR/platforms/iwing-mrf/tools $ ./config-mote.py E.g., set address to 234 and PAN ID to 555  $ ./config-mote.py --address 234 --panid 555 Set channel to 0x1A  $ ./config-mote.py --channel 0x1A 11

  12. Configure Radio (IWING-JN) Set the following variables via make   DEFAULT_ADDR  DEFAULT_PANID  DEFAULT_CHANNEL Example:  $ make PLATFORM=iwing-jn DEFAULT_ADDR=50 12

  13. Radio Message Format Type Seq No. App Data Check 802.15.4 Header (1 byte) (1 byte) (max ~100 bytes) sum Type and application data are provided by  the application via Radio API 13

  14. Radio API ( motelib/radio.h ) Broadcast a message (type=7) containing  "HELLO" to all neighbors  Call txDone() when message has been sent radioRequestTx(BROADCAST_ADDR, 7, "HELLO", 5, txDone); : void txDone(RadioStatus status) { : }  Use NULL when callback is not needed radioRequestTx(BROADCAST_ADDR, 7, "HELLO", 5, NULL); 14

  15. Radio API (cont'd) Set a handler to process received  messages radioSetRxHandler(receive); : void receive(Address src, MessageType type, void *msg, uint8_t len) { : } 15

  16. Example: sense-to-base.c Every second, each sensor node measures light  intensity and reports to the base station Assume base station has address = 0  Base station reports light measurements over  UART Base station Sensor node Sensor nodes measuring light intensity 16

  17. sense-to-base.c #include <motelib/system.h> void sense(Timer *t) #include <motelib/timer.h> { #include <motelib/radio.h> actorSetState(ACTOR_0, 1); #include <motelib/sensor.h> sensorRequestAnalog( #include <motelib/actor.h> SENSOR_1, senseDone); } Timer t; void sense(Timer *t); void senseDone( uint16_t value) void senseDone( uint16_t value); { radioRequestTx(0, 1, &value, void boot() sizeof (value), NULL); { actorSetState(ACTOR_0, 0); timerCreate(&t); } timerStart( &t, TIMER_PERIODIC, 1000, sense); } 17

  18. base.c #include <stdio.h> #include <motelib/system.h> #include <motelib/radio.h> #include <motelib/uart.h> void receive(Address src, MessageType type, void *msg, uint8_t len) { if (type == 1) { printf("Node %d: Light = %d\n", src, *(( uint16_t *)msg)); } } void boot() { uartEnable(true,true); radioSetRxHandler(receive); } 18

  19. Exercise: Voting Machine Create an application for wireless voting  machine  Allow user to cast a vote using the USER button  Voting choices are: Red (1), Yellow (2), Green (3), or No Vote (0)  When the USER button is pressed, Set LED status accordingly  Report current vote to the base station (#1) with  message type 50 19

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