2011/9/301wireless sensor network and labs fall 2011

2011/9/30 1Wireless Sensor Network And Labs fall 2011

OutlinePlatforms and microcontrollers

Software

Electronics, schematics and datasheets

2011/9/30Wireless Sensor Network And Labs fall 2011 2

WSN PlatformA hardware device that enable wireless

sensor network researchTypical components

MicrocontrollerRadioPower supplySensors and/or actuatorsPeripherals

USB interface Storage


What Do We HaveTelosB (Taroko/TmoteSky/TIP700CM)

Original design: UC Berkeley


Crossbow TelosB

Moteiv Tmote Sky

CHNDS Taroko

Maxfor TIP700CM

CrossbowOriginal design: UC Berkeley

Commercial product: Crossbow

Other products from Crossbow Cricket Imote2 IRIS


Mica2MicaZ

IRISImoteCricket

Others (Research)BTnode (ETH Zurich)

Commercialized

XYZ (Yale University)

MSB (Freie Universitat Berlin)Modular Sensor Board (MSB)


Others (Commercial)Dustnetworks (spun out of UC Berkeley)

iDwaRF – NodeBoard

Worldsens – WSN430


Others (Industrial Control)Accsense

MicroStrain

Sensicast


Now !


TarokoOriginal design version TelosB

by UC BerkeleyModified version

Taroko (CHNDS, Taiwan)TelosB (Crossbow, USA)Tmote Sky (Moteiv, USA)TIP700CM (Maxfor, Korea)


On TarokoMicrocontroller

TI (Texas Instruments) MSP430F1611RadioTI Chipcon CC2420250kbps, 2.4GHzUSB interface8M-bit flash memoryExtension connectorsOptional sensorsLight, Humidity and Temperature


Microcontroller (MCU)The heart of the WSN platform

Control everything

It is all about programming this chip


What Is A MicrocontrollerNo general definitionCommon features

low speed Microcontroller -> ARM/DSP -> Pentium/AMD

no hierarchical MemoryBits – usually 8-bit, or 16-bitPower – consume less powerCost – usually it is much cheaperInput/Output (I/O) peripherals

many on chip peripherals available


List of MCUTexas Instruments (TI): MSP430Silabs: C8051Fxxx

There are many other companies making 8051 architecture microcontrollers

including Intel, Atmel, Dallas Semiconductor, and etc.

Microchip Technology: PICAtmel: ATmega128Freescale Semiconductor (Motorola): 68HCxxMany others

AMCC (IBM), Altera, Cypress MicroSystems, Infineon, Holtek, National Semiconductor, Parallax, Rabbit Semiconductor, NEC, STMicroelectronics, Analog Devices, Xemics, ZiLOG, NXP, OKI semiconductor, Renesas Technology, Samsung, and etc.


Today’s Personal Computer


Memory (DRAM)>1GB

CPU

IDE

SATA

Audio

VGAEthern

etFirewir

eWifi

USBComPo

rt

Peripherals

Keyboard, Mouse,

Monitor, Printer, etc

Motherboard

DMA

Storage (Harddisk)>120GB

Microcontroller Block Diagram


Clock System

Memory (RAM)10KB

ALU

GPIO

Timer

ADC

UART

SPI

I2C

DAC

USBEthern

et

Peripherals

Sensors and actuators

External storage, other

ICs, other circuits

Host PC, PDA, etc.

Microcontroller

DMA

Storage (Flash)48KB

Pins


Clock System

LEDsSwitches

Radio Chip

Motor

USB Chip

PC

Light Sensors

Temp/HumiditySensor

Infrared Sensors

MSP430 Family16-bit Reduced Instruction Set

Computer (RISC) CPU1K to 128K bytes Flash128 bytes to 10K bytes RAM14- to 100-pin I/O Ultra-low Power


Clock SignalAn oscillate signal generated by some

hardware

All processors, as well as many peripherals require clocks

Clock frequency is the speed of the processor

Usually, higher speed consume large energy


CrystalsA small block of quartz

Apply a voltage, it will vibrate

For a block of given size, it will vibrate at a

given and fixed frequency

They require a drive circuit to make them go


Generate ClockOscillator module

include crystal and drive circuit

Internal drive circuit + crystalmost common case

Digitally Controlled Oscillatoran oscillator circuit constructed

by some electrical componentscan control its frequencyfrequency varies with

temperature, voltage, and from device to device


MSP430 Clock system

Flexible clock sourcesAlways-on low frequency crystal (eg. 32.768KHz)On-demand high speed DCO (up to 25MHz)

DCO on and stable in < 1μs


Flexible Clock Sources in MSP430Oscillator consume energyHigher the speed, larger the energy

consumptionUse high speed DCO

for CPU for high speed peripheralswake up and get things done, go to sleep as

soon as possibleUse low frequency crystal oscillator

for peripherals that require always onSave energy


An Example: RTCReal-Time clock (RTC)

software routine that records second, minute, and hour

Calendar clocksecond, minute, hour, day, month, year.

Implementationconfigure a timer (counter), use low frequency

osc. (32.768KHz) as clock sourcewhen the timer counts to 32768 (exactly 1

second), it generates an interruptprocessor wake-up, execute the RTC routines


MemoryRAM (Random Access Memory)

volatile storagestore variables, stack, and etc.

Flashnon volatile storagestore program code, and data

Info Segments (on MSP430)A special segment in flashUsually use to store parameters


Memory Map of MSP430

PeripheralsTo communicate with the external worldSensors

switches, light, temperature, accelerometer, infrared, humidity, pressure, acoustic, camera, and etc.

Actuators and output controlsmotor, on/off control, LEDs, LCD display, and

etc.Other ICs or circuit

flash memory IC, SD card, USB flash disk, DSP processor, and etc.

Host PC, PDA, Industry PC, and etc.2011/9/30

Wireless Sensor Network And Labs fall 2011 26

Ways to CommunicateProgrammed I/O

The processor accepts or delivers data at times convenient to it

Interrupt-driven I/OExternal events control the processor by

requesting the current program be suspended and the external event be serviced

Direct Memory Access (DMA)DMA allows data to be transferred from I/O

devices to memory directly without the continuous involvement of the processor


Microcontroller Block Diagram


Clock System

Memory (RAM)10KB

ALU

GPIO

Timer

ADC

UART

SPI

I2C

DAC

USBEthern

et

Peripherals

Sensors and actuators

External storage, other

ICs, other circuits

Host PC, PDA, etc.

Microcontroller

DMA

Storage (Flash)48KB

GPIOGeneral purpose input/outputA pin on the MicrocontrollerFunction

Set as input or outputWhen input

Read the “value” on the pin (high/low) Generate an interrupt when transition occur

When output Set the output of the pin to high/low voltage

Usage Control LEDs, read switches input, communication,

etc2011/9/30


TimerIt is a counterMeasures time intervals


Internal Clock

SourceTimer

External Source

Setting

Generate Interrupt

PWM

Other Outputs(ex. count to

32768)

(ex. 32.768kHz Crystal)

Analog to Digital Converter(ADC)Convert Voltage to a digital numberSignal Path


Sensors Signal Conditioning

(if necessary)

Convert to voltage

• Amplification• Filtering

• Light• Temperature• Acceleration• Humidity• Pressure• etc.

• Resistance• Capacitance• Current• Voltage• etc.

Analog to Digital

Conversion

(ADC)

10011101

Produce a proper output

voltage level

Converts voltage to

digital number

Digital CommunicationsSending bits between each other

Serial communicationSending bits one by oneUART, SPI, I2C, USB, etc.

Parallel communicationSending multiple bits at one timeEthernet

A B10011101

A B1 0 0 1 1 1 0 1

A B

1

111

1

00

0

Our focus


Pins


Clock System

LEDsSwitches

Radio Chip

Motor

USB Chip

PC

Light Sensors

Temp/HumiditySensor

Infrared Sensors

ArduinoHardware

platformOpen source

Based on ATmega8MCU

Cheap, easily availableSparkfun


Arduino ShieldsBoards that can be plugged on top of the

Arduino PCB


Arduino Projects2d accelerometer + flash 3d stars

http://www.youtube.com/watch?v=49WBPIIo3EE

InteractionSoapBox based on Arduinohttp://www.youtube.com/watch?v=TwhOYmNC

qrgPiezo Film + flash

http://www.youtube.com/watch?v=nXLDyBFsqdg

Weekend Project: Arduino Rumble Robotshttp://www.youtube.com/watch?v=Qc6DKDFw

g9c2011/9/30Wireless Sensor Network And Labs fall 2011 36

Taroko “Shields”


Robot Cars


TI Embedded Processing Portfolio32-bit ARM

Cortex™-M3MCUs

16-bit ultra-low power MCUs

DSPDSP+ARM

ARM Cortex-A8 MPUs

Stellaris®

ARM® Cortex™-M3MSP430™Sitara™

ARM® Cortex™-A8& ARM9

C6000™

DaVinci™video processors

TI Embedded ProcessorsDigital Signal Processors (DSPs)Microcontrollers (MCUs) ARM®-Based Processors

OMAP™

Software & Dev. Tools

Up to 100 MHz

Flash8 KB to 256 KB

USB, ENET MAC+PHY CAN, ADC, PWM, SPIConnectivity, Security,Motion Control, HMI,Industrial Automation$1.00 to $8.00

300MHz to >1GHz

Cache, RAM, ROMUSB, CAN,PCIe, EMAC Industrial computing, POS & portable data terminals$5.00 to $20.00

Up to 25 MHz

Flash1 KB to 256 KB Analog I/O, ADCLCD, USB, RF

Measurement,Sensing, General Purpose

$0.25 to $9.00

300MHz to >1Ghz +Accelerator

Cache RAM, ROM

USB, ENET, PCIe, SATA, SPI

Floating/Fixed PointVideo, Audio, Voice,Security, Conferencing $5.00 to $200.00

32-bit real-time MCUs

C2000™

Delfino™

Piccolo™

40MHz to 300 MHz

Flash, RAM16 KB to 512 KB

PWM, ADC, CAN, SPI, I2CMotor Control, Digital Power, Lighting, Ren. Enrgy

$1.50 to $20.00

Ultra Low power DSP

C5000™

Up to 300 MHz+Accelerator

Up to 320KB RAMUp to 128KB ROMUSB, ADC McBSP, SPI, I2C

Audio, Voice

Medical, Biometrics

$3.00 to $10.00

Multi-coreDSP

C6000™

24.000 MMACS

Cache RAM, ROM

SRIO, EMACDMA, PCIe

Telecom test & meas, media gateways, base stations$40 to $200.00


MSP430F1xx


MSP430F4xx


MSP430F2xx



What Has Changed?1xx 2xx 4xx 5xx

Basic Clock System Basic Clock System + FLL, FLL + Unified Clock System UCS

Core voltage same as supply voltage



Programmable Core Voltage with integrated PMM

16-bit CPU 16-bit CPU, CPUX 16-bit CPU, CPUX 16-bit CPUXV2

GPIO GPIO w/ pull-up and pull-down

GPIO GPIO w/pull-up and pull-down, drive strength

N/A N/A N/A CRC16

Software RTC Software RTC Software RTC with Basic Timer, Basic Timer + RTC

True 32-bit RTC w/Alarms

USART USCI, USI USART, USCI USCI, USB, RF

DMA up to 3-ch DMA up to 3-ch DMA up to 3-ch DMA up to 8-ch

MPY16 MPY16 MPY16, MPY32 MPY32

ADC10,12 ADC10,12 ADC12 ADC12_A

4-wire JTAG 4-wire JTAG, some devices with Spy-Bi-Wire

4-wire JTAG 4-wire JTAG and Spy-Bi-Wire


F5xx vs. Prior MSP430 Generations2xx 4xx 5xx

CPU Clock (max) 16MHz 8MHz 25MHz

*Active Current

(3.0V, typ)

515uA @ 1MHz

4.2mA @ 8MHz

9.1mA @ 16MHz

600uA @ 1MHz

4.8mA @ 8MHz

N/A

290uA @ 1MHz

1.84mA @ 8MHz 230 uA/MHz

8.90mA @ 25MHz

120KB / 8KB (Flash / RAM) 120KB / 8KB (Flash / RAM) 256KB / 16KB (Flash / RAM)

Wake-up Time From LPM3 1us 6us 5us

Standby LPM3 Current 0.9 – 1.1uA 1.1 – 2.5uA 2.6uA (with active true RTC)

LPM4 Current 0.1uA 0.1uA 1.6uA (LPM4) / 0.1uA (LPM5)

Flash ISP Minimum DVCC 2.2V 2.7V 1.8V

Port I/O Interrupt Capability P1/P2 P1/P2 P1/P2

Some devices also P3/P4

Prog. Port Pin Drive Strength N/A N/A All port pins

Prog. Pull-ups/-downs All port pins N/A All port pins

Available MCLK Sources DCO

LFXT1

XT2 (if available)

VLO

FLL

LFXT1

XT2 (if available)

FLL

LFXT1

UCS XT2 (if available)

VLO

REFO

Available FLL Reference Clocks

N/A LFXT1 LFXT1, REFO, & XT2 (if available)

MSP430 Roadmap

100+ devices

2xx-Catalog• 16 MIPS• 120 kB Flash• 8 kB RAM• 500 nA Standby• 1.8 – 3.6V

75+ devices

1xx-Catalog• 8MIPS• 60 kB Flash• 10 kB RAM• 1.8 – 3.6 V

G = Value LineF = FlashFR = FRAM

100+ devices

4xx: LCD • 16 MIPS• 120 kB Flash• 8 kB RAM• LCD Controller, 160

segments• 1.8 – 3.6V

F23x0

The New Generation

5xx-6xx• 25MIPS• 256 kB Flash• 16 kB RAM• 1.8 – 3.6V• FRAM, USB, RF• 6xx: LCD Controller• 160 uA/MIPS

Production

Development

Device

F23x-F24x

F261xF241x

F20xxF21x1

F21x2

F22xx

F13x-F14xF15x-F16x

F541x F543xA

Fx42x0Fx42x

F44x

Fx43x

FG461x

FE42x2

F47x4

Fx47xF43x

F23x0

F11xxF12xx

F41xF41x2

FR57xxFRAM

F550x USB

F51x2Lighting

L0920.9V Native

F53xxGen Purpose

F6/563xBGM, Catalog

G2xx1

F552xUSB

CC430RF

G2xx2G2xx5

F471xx


The eZ430 Family of MSP430 Tools The eZ430 is a tradition of low-cost, easy-to-use tools for MSP430

Options include RF, energy-harvesting, RFID, even a wireless sports watch development kit!


Programming Tools Parallel FET

Supports ALL MSP430 devices Supports 4-Wire JTAG mode

only Fixed output voltage of 2.8V No JTAG fuse blow Simple hardware circuit,

possible to implement as part of a product

USB FET Supports ALL MSP430 devices Supports 4-Wire and 2-Wire

(Spy-Bi-Wire) JTAG Adjustable output voltage:

1.8 - 3.6V, 100mA JTAG fuse blow Fast operation


Gang Programmer GANG430


Target Boards for Device Programming

100-pin target board exclusive to the F543x(A) / F541x(A) devices

Development board with 100-pin TSSOP (PW) ZIF socket (MSP-TS430PZ5x100)

All pins brought out to pin headers for easy access

Programming via JTAG, Spy-bi-wire or BSL

A FET board exists for most variants of MSP430

Only $49


MSP430 Software ToolsWireless Networking Protocols

Z-Stack (CC2520 + MSP430F5438 ZigBee)TI-MACSimpliciTI (on MSP430 MediaWiki) DASH7 Wireless M-Bus6LoPAN

Example Code for the MSP-EXP430F5438 Experimenter Board (www.ti.com/msp430tools)Drivers for hardware peripherals, LCD, USB conn.

Operating SystemsuC-OSIIIAR PowerPacSalvo FreeRTOS2011/9/30


www.ti.com/msp430

User’s GuidesDatasheetsCode Libraries100+ Application Reports1000+ Code ExamplesProduct BrochureLatest Tool Software3rd Party ListingSilicon Errata


Typical PC Program


# include# define…….

main () { do something;

wait for input; terminate;}

1. Other sub-functions ()

External response (mouse/keyboard)

Typical Structure of Our Program


# include# define…….

main () { System and Peripherals initialization

for(;;) // forever loop { 1. wait for interrupt(sleep) 2. do something after return from interrupt }}

1. Peripherals initialization routines ()

2. Other sub-functions ()

(ISR) Interrupt Service Routines () { 1. Quickly do something or Setting flags}

Internal/External Events

InitializationConfigure hardware into a proper stateHow to configure

set registersRegisters

each hardware subsystem has its own registersstore configuration, status, buffer, and etc.set these registers properly in order to get it

worksHow to set the registers properly

MSP430x1xx family user ‘s guide2011/9/30


InterruptA specific internal/external event occur that

suspend current program

Mostly, it is defined by you

some exceptions, for example – reset

Usually, you have to handle it immediately

You have to define how to react while this

event occur


maskable/non-maskableNon-maskable interrupts

Interrupts that cannot be disableeg. reset, oscillator fault

Maskable interruptsInterrupts that can be disable in the programMost of the interrupts you need to handle is

maskable


What happen when it occur


main() {

for(;;) { MCU is executing or sleeping }}

1. Set interrupt flag2. Main program suspended3. Store state variables 4. Jump to ISR

(ISR) Interrupt Service Routines () { 1. Quickly do something or setting flags}

2. Restore state variables3. Return to main program, resume process

Interrupt flag: a special register indicates a particular interrupt occurState variables: information CPU will need to resume to normal processing

Where to JumpInterrupt vector

a special segment in the memorystore the address of the ISRby following code

#progma vector=0xFFFA__interrupt void Timer_B0 (void)

where is the interrupt vector specified in datasheet


Memory Map of MSP430

Address of Interrupt Vector

More than oneMore than one interrupts occur simultaneously

serve higher priority firstWhen one interrupt is being serve, it will

disable the other interruptsmeans the other ISR cannot execute before this

one finishif more than one occur while serving one

interrupt wait until it finish, serve the highest priority one first

You can enable interrupt in the ISRnot recommended


Masked twiceWhile interrupt A is being serve, interrupt B

occurred, twicewhen interrupt A is finished, the ISR of

interrupt B will be serve, only onceyou miss one event!!

KEEP YOUR ISR SHORT!!!!


Protect Your DataExample:


Packet receive interrupt occurred{ 1. packet stored in a receive buffer 2. copy receive buffer to temporal buffer 3. return}

In main program{ 1. copy temporal buffer to some data structure 2. process data}

Another packet receive interrupt occurred in the middle of copying data

In main program{ 1. disable global interrupt 2. copy temporal buffer to some data structure 3. enable global interrupt 4. process data}

Software ArchitecturesRound Robin with Interrupts

Problem: no proirity


for(;;) // forever loop { 1. wait for interrupt(sleep) if( Event 1 occurred) { do something } if( Event 2 occurred) { do something } if( Event 3 occurred) { do something } }

(ISR) Interrupt Service Routines 1 () { 1. do critical things 2. set event 1 occurred flag}(ISR) Interrupt Service Routines 2 () { 1. do critical things 2. set event 2 occurred flag}(ISR) Interrupt Service Routines 3 () { 1. do critical things 2. set event 3 occurred flag}

Software ArchitecturesFunction-Queue-Scheduling

Worst wait for highest priority taskbounded by the longest function


for(;;) // forever loop { 1. wait for interrupt(sleep) While (function queue is not empty) { call first function on queue } }

(ISR) Interrupt Service Routines 1 () { 1. do critical things 2. put function_1 on queue}



Software ArchitecturesReal-Time Operating System (RTOS)

load an operating system into the MCUthere are many RTOS availableit is beyond the scope of this class


How To Program


FET (Flash Emulation Tool)A tool that allow you to program and debug MSP430Connects to the JTAG port on MSP430A generic term used in MSP430 world

JTAG (Joint Test Action Group)IEEE 1149.1 standard: “standard Test Access Port and

Boundary-Scan Architecture”A standard interface defined for testing and debugging

Video


TinyOS“System architecture directions for network

sensors”, Jason Hill, Robert Szewczyk, Alec Woo, Seth Hollar, David Culler, Kristofer Pister . ASPLOS 2000, Cambridge, November 2000

System software for networked sensorsTiny Microthreading Operating System: TinyOS

Component-basedEvent-driven

TinyOS is written in nesC programming language


TinyOS is very powerful Modern operating system and language

techniques in an embedded systemA lot of libraries, support code, and community

development“TinyOS has a steep learning curve”

It can take time to use all of its capabilities

Wireless Sensor Network And Labs fall 2011

Why TinyOS?

Slides from TinyOS-IPSN20092011/9/30 69

nesCnesC programming language

An extension to CDesigned for sensor network nodes

Basic concepts behind nesCSeparation of construction and composition

Many components, “wired”(link) those you wantComponent provide a set of interfacesInterfaces are bidirectional

Command (down call), event (up call)

nesC compiler signals the potential data races


Support Multiple Platforms Hardware platforms

eyesIFXv2, ETH Zurich TI MSP430F1611, Infineon TDA5250

Intelmote2, Intel PXA271 XScale Processor, TI (Chipcon) CC2420

Mica2, UCB Atmel128, TI (Chipcon) CC1000

Mica2dot, UCB Atmel128, TI (Chipcon) CC1000

Micaz, UCB Atmel128, TI (Chipcon) CC2420

Telosb, UCB (Taroko) MSP430F1611, TI (Chipcon) CC2420

Tinynode, EPFL Switzerland MSP430F1611, Semtech radio transceiver XE1205

Three different microcontrollers, four different radio transceivers and many other peripheral ICs


ContikiContiki – a dynamic operating system for

networked embedded systemsLoadable modules, multiple network stacks,

multiple threading modelsOpen source; 3-clause BSD licence

Small memory footprintDesigned for portability

14 platforms, 5 CPUs in current CVS codeMany pioneering featuresProvides IP communication, both

for IPv4 and IPv6.


Demohttp://www.youtube.com/watch?

v=ievpE6nkj0Q


Something To NoteYou won't get very far without at least a very

rudimentary understanding of electronicsBut electronics is a vast and complex fieldWhat we provide here is just some very basic

principlesWe assume you have some common sense

about electronicsWe will try to make it as simple as possible


Voltage, Current and PowerVoltage

Symbol: VUnit: Volt, (V)

CurrentSymbol: IUnit: Ampere, (A)

PowerP = V * IUnit: Watt, (W)


DC and ACDC: Direct Current

Definition: current that travels in one direction we usually refer to constant voltage

AC: Alternating CurrentDefinition: opposed to DCwe usually refer to varying voltage

DC component vs AC componentDC component: average of signalAC component: the varying signal


Relationship between V and IOhm’s Law

V = I * RResistor

Most widely used elementSymbol: RUnit: Ohm (Ω)Schematic symbol:


Variable resistor

Resistors in seriesResistors in series


=R = R1 + R2

V

V1

V2I2I1

I

21

2

1

21

2

21

1

III

RR

RVV

RR

RVV

Resistors in parallelResistor in parallel


=21

21

21

11

1

RR

RR

RR

R

V

V1

V2I2

I1

I21

2

1

21

21

1

2

21

2

1

III

RR

RI

R

VI

RR

RI

R

VI

VVV

CapacitorsCapacitor store chargeSymbol: CUnit: Farads (F)

Typical range we use is from μF to pFCircuit symbols

Bipolar: no polarityUnipolar: has a positive and a negative lead


Charge and dischargeApply a voltage chargingRemove voltage discharging

Provide a temporary voltage and current source

DecouplingStable the DC voltage source


DiodesPass a current in one direction, block it from

anotherSymbol: D Forward voltage drop

A voltage different between anode and cathodeExample

For a typical voltage drop of 0.7V If Vanode is 3.3V, than Vcathode is 2.6V

This value will be specified in datasheet


Vanode Vcathode

LEDsLight-emitting diode (LED)Limited amount of current can pass through

Will damage if current is too largeNeed a current-limiting resistor

If voltage drop of this LED is 1.6V, and we want 20mA pass through


3.3V

Ground

Vanode Vcathode

R

I

8502.07.1

7.13.3 _

IVR

VVVV dropvoltagecathode

Other componentsCrystals

Symbol: X, YSwitches

symbols: SWInductors

symbol: L


Understanding Schematic


Component

Net Labels

Power Ports

Nets Crossing

Nets Cross Multiple Sheet

Real Schematic -- Taroko


Reading DatasheetEvery component should have a datasheetContain every information about the componentIf you are designing you own embedded system

Read it thoroughly and feel you understandGo back and reread itGet the latest datasheets and errata

Lets take a look at the MSP430F1611 datasheet


Next Two LabsLab 1: GPIO

Control LEDsReading switches, keypads input

Lab 2: TimerGenerate different time intervalGenerate PWM signal, control servo motor


LEDsThis is a typical connectionWhen P1.1 set to high

DVcc = VP1.1

no current flowWhen P1.1 set to low

VP1.1 = 0Current flow through, turn on the LED

GPIO can use as an On/Off control

DVcc

Vanode Vcathode

R


SwitchesOperation

Open: A and B are not connected in normal state

Close: When you press the button, A and B are connected

Typical circuitWhen the switch is open, voltage of USERINT stay at highWhen the switch is close, voltage of will be low

A B


KeypadThis is a 3x4

matrix keypadWhen you press a

button, a pin in X and a pin in Y is connected

How to interface to MSP430?


Next Two LabsLab 1: GPIO

Control LEDsReading switches, keypads input

Lab 2: TimerGenerate different time intervalGenerate PWM signal, control servo motor


Time IntervalsGenerate different time intervals Flash different LED with different time

interval


Robot CarServo motors

Robot Power (Vcc)

RedRobot Ground

(GND) Black

Robot SignalWhite Battery

GroundBlack Battery

PowerRed


Pulse Width Modulation

Pulse Width Modulation (PWM)varying the pulse width

Usage of PWMControl motor, telecommunication, voltage

regulation, and etc.

Pulse

Pulse width

Period


Pulse

Pulse width

Period ≈ 20 ms

Servo MotorA PWM input controls it angular position

Pulse width = 1.5 ms; position = 90o (neutral)Example

pulse width = 1.25 ms; position = 0o

pulse width = 1.75 ms; position = 180o

Varies between brands and models

The servo motor we used is Continuous Rotation modelOther models will just move to the

programmed position and stop


Control Servo Motor

The servo motors we used are 1.5 ms neutralIf pulse width = 1.5 ms stopIf pulse width > 1.5 ms rotate in one directionIf pulse width < 1.5 ms rotate in another

direction

Pulse

Pulse width

Period ≈ 20 ms


Install IARWe will begin our labs next weekInstall the programming software ahead

Go to www.ti.comClick Microcontroller In MSP430 menu, click Tools & SoftwareFind IAR-KICKSTART and click on itDownload software and install


2011/9/301wireless sensor network and labs fall 2011

Documents