2011/9/30
Wireless Sensor Network And Labs fall 2011
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Outline
 Platforms and microcontrollers
 Software
 Electronics, schematics and datasheets
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Wireless Sensor Network And Labs fall 2011
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WSN Platform
 A hardware device that enable wireless sensor
network research
 Typical components
 Microcontroller
 Radio
 Power supply
 Sensors and/or actuators
 Peripherals


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USB interface
Storage
Wireless Sensor Network And Labs fall 2011
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What Do We Have
 TelosB (Taroko/TmoteSky/TIP700CM)
 Original design: UC Berkeley
CHNDS Taroko
Crossbow TelosB
Moteiv Tmote Sky
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Wireless Sensor Network And Labs fall 2011
Maxfor TIP700CM
4
Crossbow
 Original design: UC Berkeley
 Commercial product: Crossbow
Mica2
 Other products from Crossbow



Cricket
Imote2
IRIS
Cricket
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MicaZ
Wireless Sensor Network And Labs fall 2011
Imote
IRIS
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Others (Research)
 BTnode (ETH Zurich)
 Commercialized
 XYZ (Yale University)
 MSB (Freie Universitat Berlin)
 Modular Sensor Board (MSB)
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Others (Commercial)
 Dustnetworks (spun out of UC Berkeley)
 iDwaRF – NodeBoard
 Worldsens – WSN430
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Others (Industrial Control)
 Accsense
 MicroStrain
 Sensicast
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Now !
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Taroko
 Original design version  TelosB
 by UC Berkeley
 Modified version
 Taroko (CHNDS, Taiwan)
 TelosB (Crossbow, USA)
 Tmote Sky (Moteiv, USA)
 TIP700CM (Maxfor, Korea)
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On Taroko
 Microcontroller
 TI (Texas Instruments) MSP430F1611
 Radio
 TI Chipcon CC2420
 250kbps, 2.4GHz
 USB interface
 8M-bit flash memory
 Extension connectors
 Optional sensors
 Light, Humidity and Temperature
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Microcontroller (MCU)
 The heart of the WSN platform
 Control everything
 It is all about programming this chip
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What Is A Microcontroller
 No general definition
 Common features
 low speed

Microcontroller -> ARM/DSP -> Pentium/AMD
 no hierarchical Memory
 Bits – usually 8-bit, or 16-bit
 Power – consume less power
 Cost – usually it is much cheaper
 Input/Output (I/O) peripherals

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many on chip peripherals available
Wireless Sensor Network And Labs fall 2011
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List of MCU
 Texas Instruments (TI): MSP430
 Silabs: C8051Fxxx
 There are many other companies making 8051 architecture
microcontrollers
 including Intel, Atmel, Dallas Semiconductor, and etc.
 Microchip Technology: PIC
 Atmel: ATmega128
 Freescale Semiconductor (Motorola): 68HCxx
 Many 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.
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Today’s Personal Computer
Motherboard
Storage
(Harddisk)
>120GB
Peripherals
IDE
SATA
Audio
VGA
CPU
Memory
(DRAM)
>1GB
Ethernet
Keyboard, Mouse,
Monitor, Printer,
etc
Firewire
DMA
Wifi
USB
ComPort
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Microcontroller Block Diagram
Microcontroller
Clock System
Peripherals
GPIO
Timer
Sensors and
actuators
ADC
ALU
Memory
(RAM)
10KB
Storage
(Flash)
48KB
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UART
SPI
DMA
External storage,
other ICs, other
circuits
I2C
DAC
Host PC, PDA, etc.
USB
Ethernet
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Pins
Light Sensors
Temp/Humidity
Sensor
Infrared Sensors
Motor
Clock System
USB Chip
PC
Radio Chip
Switches
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LEDs
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MSP430 Family
 16-bit Reduced Instruction Set Computer
(RISC) CPU
 1K to 128K bytes Flash
 128 bytes to 10K bytes RAM
 14- to 100-pin I/O
 Ultra-low Power
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Clock Signal
 An 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
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Crystals
 A 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
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Generate Clock
 Oscillator module
 include crystal and drive circuit
 Internal drive circuit + crystal
 most common case
 Digitally Controlled Oscillator
 an oscillator circuit constructed by
some electrical components
 can control its frequency
 frequency varies with temperature,
voltage, and from device to device
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MSP430 Clock system
 Flexible clock sources
 Always-on low frequency crystal (eg. 32.768KHz)
 On-demand high speed DCO (up to 25MHz)
 DCO on and stable in < 1μs
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Flexible Clock Sources in MSP430
 Oscillator consume energy
 Higher the speed, larger the energy consumption
 Use high speed DCO
 for CPU
 for high speed peripherals
 wake up and get things done, go to sleep as soon as
possible
 Use low frequency crystal oscillator
 for peripherals that require always on
 Save energy
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An Example: RTC
 Real-Time clock (RTC)
 software routine that records second, minute, and hour
 Calendar clock
 second, minute, hour, day, month, year.
 Implementation
 configure a timer (counter), use low frequency osc.
(32.768KHz) as clock source
 when the timer counts to 32768 (exactly 1 second), it
generates an interrupt
 processor wake-up, execute the RTC routines
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Memory
 RAM (Random Access Memory)
 volatile storage
 store variables, stack, and etc.
 Flash
 non volatile storage
 store program code, and data
 Info Segments (on MSP430)
 A special segment in flash
 Usually use to store parameters
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Memory Map of MSP430
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Peripherals
 To communicate with the external world
 Sensors
 switches, light, temperature, accelerometer, infrared,
humidity, pressure, acoustic, camera, and etc.
 Actuators and output controls
 motor, 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.
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Ways to Communicate
 Programmed I/O
 The processor accepts or delivers data at times
convenient to it
 Interrupt-driven I/O
 External 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
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Microcontroller Block Diagram
Microcontroller
Clock System
Peripherals
GPIO
Timer
Sensors and
actuators
ADC
ALU
Memory
(RAM)
10KB
Storage
(Flash)
48KB
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UART
SPI
DMA
External storage,
other ICs, other
circuits
I2C
DAC
Host PC, PDA, etc.
USB
Ethernet
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GPIO
 General purpose input/output
 A pin on the Microcontroller
 Function
 Set as input or output
 When 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, etc
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Timer
 It is a counter
 Measures time intervals
Generate
Interrupt
(ex. 32.768kHz Crystal)
Internal
Clock Source
Timer
External
Source
Setting
(ex. count to 32768)
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PWM
Wireless Sensor Network And Labs fall 2011
Other Outputs
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Analog to Digital Converter(ADC)
 Convert Voltage to a digital number
 Signal Path
Signal Conditioning
Sensors
• Light
• Temperature
• Acceleration
• Humidity
• Pressure
• etc.
Produce a
proper output
voltage level
(if necessary)
• Resistance
• Capacitance
• Current
• Voltage
• etc.
• Amplification
• Filtering
Convert to
voltage
Analog to
Digital
Conversion
(ADC)
10011101
Converts
voltage to
digital number
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Digital Communications
 Sending bits between each other
10011101
A
B
 Serial communication
Our focus
10011101
 Sending bits one by one
A
 UART, SPI, I2C, USB, etc.
 Parallel communication
1
0
 Sending multiple bits at one time
0
1
1
A
 Ethernet
1
B
B
0
1
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Pins
Light Sensors
Temp/Humidity
Sensor
Infrared Sensors
Motor
Clock System
USB Chip
PC
Radio Chip
Switches
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Wireless Sensor Network And Labs fall 2011
LEDs
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Arduino
 Hardware platform
 Open source
 Based on ATmega8
 MCU
 Cheap, easily available
 Sparkfun
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Arduino Shields
 Boards that can be plugged on top of the Arduino PCB
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Arduino Projects
 2d accelerometer + flash 3d stars
 http://www.youtube.com/watch?v=49WBPIIo3EE
 InteractionSoapBox based on Arduino
 http://www.youtube.com/watch?v=TwhOYmNCqrg
 Piezo Film + flash
 http://www.youtube.com/watch?v=nXLDyBFsqdg
 Weekend Project: Arduino Rumble Robots
 http://www.youtube.com/watch?v=Qc6DKDFwg9c
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Wireless Sensor Network And Labs fall 2011
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Taroko “Shields”
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Robot Cars
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Wireless Sensor Network And Labs fall 2011
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TI Embedded Processors
TI Embedded
Processing
Portfolio
ARM®-Based Processors
Microcontrollers (MCUs)
16-bit ultralow power
MCUs
MSP430™
32-bit
real-time
MCUs
C2000™
Delfino™
Piccolo™
32-bit ARM
Cortex™-M3
MCUs
Stellaris®
ARM®
Cortex™-M3
ARM
Cortex-A8
MPUs
ARM® Cortex™-A8
& ARM9
C6000™
DaVinci™
Up to
100 MHz
300MHz to
>1GHz
Flash
1 KB to 256 KB
Analog I/O, ADC
LCD, USB, RF
Flash, RAM
16 KB to 512 KB
Flash
8 KB to 256 KB
Measurement,
Sensing, General
Purpose
PWM, ADC,
CAN, SPI, I2C
Motor Control,
Digital Power,
Lighting, Ren. Enrgy
USB, ENET
MAC+PHY CAN,
ADC, PWM, SPI
Cache,
RAM, ROM
USB, CAN,
PCIe, EMAC
Connectivity, Security,
Motion Control, HMI,
Industrial Automation
$1.00 to $8.00
Industrial computing,
POS & portable
data terminals
$5.00 to $20.00
Multi-core
DSP
C6000™
Ultra
Low power
DSP
C5000™
video processors
OMAP™
40MHz to
300 MHz
$1.50 to $20.00
DSP
DSP+ARM
Sitara™
Up to
25 MHz
$0.25 to $9.00
Digital Signal Processors (DSPs)
300MHz to >1Ghz
+Accelerator
Cache
RAM, ROM
USB, ENET,
PCIe, SATA, SPI
Floating/Fixed Point
Video, Audio, Voice,
Security, Conferencing
$5.00 to $200.00
24.000
MMACS
Up to 300 MHz
+Accelerator
Cache
RAM, ROM
Up to 320KB RAM
Up to 128KB ROM
USB, ADC
McBSP, SPI, I2C
SRIO, EMAC
DMA, PCIe
Telecom test & meas,
media gateways,
base stations
$40 to $200.00
Audio, Voice
Medical, Biometrics
$3.00 to $10.00
Software & Dev. Tools
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Wireless Sensor Network And Labs fall 2011
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MSP430F1xx
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MSP430F4xx
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MSP430F2xx
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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
Core voltage same as supply
voltage
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-BiWire
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F5xx vs. Prior MSP430 Generations
2xx
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)
N/A
LFXT1
Available FLL Reference
Clocks
2011/9/30
UCS
FLL
LFXT1
XT2 (if available)
VLO
REFO
LFXT1, REFO, & XT2 (if
available)
Wireless Sensor Network And Labs fall 2011
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MSP430 Roadmap
FR57xx
BGM, Catalog
Production
F53xx
Development
F51x2
16 MIPS
120 kB Flash
8 kB RAM
500 nA Standby
1.8 – 3.6V
G = Value Line
F = Flash
FR = FRAM
F23x0
F23x0
G2xx2
1xx-Catalog
•
•
•
•
8MIPS
60 kB Flash
10 kB RAM
1.8 – 3.6 V
•
•
•
•
•
•
•
F543xA
F541x
F15x-F16x
F13x-F14x
G2xx5
75+ devices
5xx-6xx
F21x2
F20xx
G2xx1
The New Generation
RF
USB
F22xx
F21x1
0.9V Native
CC430
F552x
F12xx
FG461x
Fx43x
F44x
F11xx
Fx42x
Fx42x0
F41x
FE42x2
F41x2
Wireless Sensor Network And Labs fall 2011
25MIPS
256 kB Flash
16 kB RAM
1.8 – 3.6V
FRAM, USB, RF
6xx: LCD Controller
160 uA/MIPS
F471xx
F43x
Fx47x
F47x4
USB
L092
Lighting
F261x
F241x
F23x-F24x
2xx-Catalog
•
•
•
•
•
F550x
Gen Purpose
100+ devices
2011/9/30
FRAM
F6/563x
Device
100+ devices
4xx: LCD
•
•
•
•
16 MIPS
120 kB Flash
8 kB RAM
LCD Controller, 160
segments
• 1.8 – 3.6V
45
The eZ430 Family of MSP430 Tools
The eZ430 is a tradition of low-cost,
easy-to-use tools for MSP430

Options include RF, energyharvesting, RFID, even a wireless
sports watch development kit!

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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
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Gang Programmer GANG430
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Target Boards for Device Programming
 100-pin target board exclusive to the





2011/9/30
F543x(A) / F541x(A) devices
Development board with 100-pin
TSSOP (PW) ZIF socket (MSPTS430PZ5x100)
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
Wireless Sensor Network And Labs fall 2011
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MSP430 Software Tools
 Wireless Networking Protocols
 Z-Stack (CC2520 + MSP430F5438 ZigBee)
 TI-MAC
 SimpliciTI (on MSP430 MediaWiki)
 DASH7
 Wireless M-Bus
 6LoPAN
 Example Code for the MSP-EXP430F5438 Experimenter
Board (www.ti.com/msp430tools)
 Drivers for hardware peripherals, LCD, USB conn.
 Operating Systems
 uC-OSII
 IAR PowerPac
 Salvo

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FreeRTOS
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www.ti.com/msp430









User’s Guides
Datasheets
Code Libraries
100+ Application Reports
1000+ Code Examples
Product Brochure
Latest Tool Software
3rd Party Listing
Silicon Errata
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Typical PC Program
# include
# define
…….
1. Other sub-functions ()
main ()
{
do something;
wait for input;
terminate;
}
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External response
(mouse/keyboard)
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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 ()
Internal/External Events
(ISR) Interrupt Service
Routines ()
{
1. Quickly do something
or Setting flags
}
}
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Initialization
 Configure hardware into a proper state
 How to configure
 set registers
 Registers
 each hardware subsystem has its own registers
 store configuration, status, buffer, and etc.
 set these registers properly in order to get it works
 How to set the registers properly
 MSP430x1xx family user ‘s guide
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Interrupt
 A 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
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maskable/non-maskable
 Non-maskable interrupts
 Interrupts that cannot be disable
 eg. reset, oscillator fault
 Maskable interrupts
 Interrupts that can be disable in the program
 Most of the interrupts you need to handle is maskable
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What happen when it occur
1.
2.
3.
4.
main()
{
for(;;)
{
MCU is executing
or sleeping
}
}
Set interrupt flag
Main program suspended
Store state variables
Jump to ISR
(ISR) Interrupt Service Routines ()
{
1. Quickly do something
or setting flags
}
2. Restore state variables
3. Return to main program, resume
process
Interrupt flag: a special register indicates a particular interrupt occur
State variables: information CPU will need to resume to normal processing
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Where to Jump
Memory Map of MSP430
 Interrupt vector
 a special segment in the memory
 store the address of the ISR
 by following code
Address of
Interrupt Vector
#progma vector=0xFFFA
__interrupt void Timer_B0 (void)
 where is the interrupt vector

2011/9/30
specified in datasheet
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More than one
 More than one interrupts occur simultaneously
 serve higher priority first
 When one interrupt is being serve, it will disable the
other interrupts
 means the other ISR cannot execute before this one
finish
 if more than one occur while serving one interrupt

wait until it finish, serve the highest priority one first
 You can enable interrupt in the ISR
 not recommended
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Masked twice
 While interrupt A is being serve, interrupt B occurred,
twice
 when interrupt A is finished, the ISR of interrupt B will
be serve, only once
 you miss one event!!
 KEEP YOUR ISR SHORT!!!!
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Protect Your Data
 Example:
Packet receive interrupt occurred
{
1. packet stored in a receive buffer
2. copy receive buffer to temporal buffer
3. return
}
In main program
{In main program
{ 1. disable global interrupt
1. copy temporal buffer to some data structure
2.
2. enable
processglobal
data interrupt
3.
} 4. process data
}
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Another packet receive
interrupt occurred in the
middle of copying data
62
Software Architectures
 Round Robin with Interrupts
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
}
}
 Problem: no proirity
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(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
}
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Software Architectures
 Function-Queue-Scheduling
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
}
(ISR) Interrupt Service Routines 2 ()
{
1. do critical things
2. put function_2 on queue
}
(ISR) Interrupt Service Routines 3 ()
{
1. do critical things
2. put function_3 on queue
}
 Worst wait for highest priority task
 bounded by the longest function
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Software Architectures
 Real-Time Operating System (RTOS)
 load an operating system into the MCU
 there are many RTOS available
 it is beyond the scope of this class
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How To Program
 FET (Flash Emulation Tool)
 A tool that allow you to program and debug MSP430
 Connects to the JTAG port on MSP430
 A 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
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Video
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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 sensors
 Tiny Microthreading Operating System: TinyOS
 Component-based
 Event-driven
 TinyOS is written in nesC programming language
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Why TinyOS?
 TinyOS is very powerful
 Modern operating system and language techniques in an
embedded system
 A lot of libraries, support code, and community
development
 “TinyOS has a steep learning curve”
 It can take time to use all of its capabilities
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Slides from TinyOS-IPSN2009
69
nesC
 nesC programming language
 An extension to C
 Designed for sensor network nodes
 Basic concepts behind nesC
 Separation of construction and composition

Many components, “wired”(link) those you want
 Component provide a set of interfaces
 Interfaces are bidirectional
 Command (down call), event (up call)
 nesC compiler signals the potential data races
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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
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Contiki
 Contiki – a dynamic operating system for networked
embedded systems
 Loadable modules, multiple network stacks, multiple
threading models
 Open source; 3-clause BSD licence
 Small memory footprint
 Designed for portability
 14 platforms, 5 CPUs in current CVS code
 Many pioneering features
 Provides IP communication, both for IPv4 and IPv6.
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Demo
 http://www.youtube.com/watch?v=ievpE6nkj0Q
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Something To Note
 You won't get very far without at least a very
rudimentary understanding of electronics
 But electronics is a vast and complex field
 What we provide here is just some very basic
principles
 We assume you have some common sense about
electronics
 We will try to make it as simple as possible
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Voltage, Current and Power
 Voltage
 Symbol: V
 Unit: Volt, (V)
 Current
 Symbol: I
 Unit: Ampere, (A)
 Power
 P=V*I
 Unit: Watt, (W)
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DC and AC
 DC: Direct Current
 Definition: current that travels in one direction
 we usually refer to constant voltage
 AC: Alternating Current
 Definition: opposed to DC
 we usually refer to varying voltage
 DC component vs AC component
 DC component: average of signal
 AC component: the varying signal
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Relationship between V and I
 Ohm’s Law
 V=I*R
 Resistor
 Most widely used element
 Symbol: R
 Unit: Ohm (Ω)
 Schematic symbol:
Variable resistor
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Resistors in series
 Resistors in series
R = R1 + R2
=
I1
I
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V1
I2
V
V2
 R1 
V1  V  

 R1  R 2 
 R2 
V2  V  

 R1  R 2 
I  I1  I 2
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Resistors in parallel
 Resistor in parallel
R
=
I1
I2
I
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V1
V2
V
1
1
R1
1

R2
R1  R2
R1  R2
V  V1  V2
V 
 R2 
I1     I  

R
1
R
1

R
2
 


V 
 R1 
I2  

I




R
2
R
1

R
2




I  I1  I 2
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Capacitors
 Capacitor store charge
 Symbol: C
 Unit: Farads (F)
 Typical range we use is from μF to pF
 Circuit symbols
 Bipolar: no polarity
 Unipolar: has a positive and a negative lead
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Charge and discharge
 Apply a voltage  charging
 Remove voltage  discharging
 Provide a temporary voltage and current source
 Decoupling
 Stable the DC voltage source
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Diodes
 Pass a current in one direction, block it from another
 Symbol: D
 Forward voltage drop
Vanode
Vcathode
 A voltage different between anode and cathode
 Example


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
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LEDs
 Light-emitting diode (LED)
 Limited amount of current can pass through
 Will damage if current is too large
 Need a current-limiting resistor
I
R
3.3V
Vanode
Vcathode
Ground
Vcathode  3.3V  Vvoltage_ drop  1.7V
R  V  1.7
 85
I
0.02
 If voltage drop of this LED is 1.6V, and we want 20mA
pass through
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Other components
 Crystals
 Symbol: X, Y
 Switches
 symbols: SW
 Inductors
 symbol: L
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Understanding Schematic
Net Labels
Component
Power Ports
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Nets Cross
Multiple Sheet
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Real Schematic -- Taroko
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Reading Datasheet
 Every component should have a datasheet
 Contain every information about the component
 If you are designing you own embedded system
 Read it thoroughly and feel you understand
 Go back and reread it
 Get the latest datasheets and errata
 Lets take a look at the MSP430F1611 datasheet
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Next Two Labs
 Lab 1: GPIO
 Control LEDs
 Reading switches, keypads input
 Lab 2: Timer
 Generate different time interval
 Generate PWM signal, control servo motor
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LEDs
 This is a typical connection
 When P1.1 set to high
 DVcc = VP1.1
 no current flow
DVcc
Vanode Vcathode
 When P1.1 set to low
 VP1.1 = 0
 Current flow through, turn on the LED
R
 GPIO can use as an On/Off control
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Switches
A
B
 Operation
 Open: A and B are not connected in normal state
 Close: When you press the button, A and B are
connected
 Typical circuit
 When the switch is open, voltage of
USERINT stay at high
 When the switch is close, voltage of
will be low
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Keypad
 This is a 3x4 matrix
keypad
 When you press a
button, a pin in X and
a pin in Y is
connected
 How to interface to
MSP430?
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Next Two Labs
 Lab 1: GPIO
 Control LEDs
 Reading switches, keypads input
 Lab 2: Timer
 Generate different time interval
 Generate PWM signal, control servo motor
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Time Intervals
 Generate different time intervals
 Flash different LED with different time interval
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Robot Car
Servo
motors
Robot Power
(Vcc) Red
Robot Ground
(GND) Black
Robot Signal
White
Battery Ground
Black
Battery Power
Red
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Pulse Width Modulation
Pulse width
Pulse
Period
 Pulse Width Modulation (PWM)
 varying the pulse width
 Usage of PWM
 Control motor, telecommunication, voltage regulation,
and etc.
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Servo Motor
 A PWM input controls it angular position
 Pulse width = 1.5 ms; position = 90o (neutral)
Pulse
 Example


Pulse width
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
Period ≈ 20 ms
Rotation model
 Other models will just move to the
programmed position and stop
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Control Servo Motor
Pulse width
Pulse
Period ≈ 20 ms
 The servo motors we used are 1.5 ms neutral
 If pulse width = 1.5 ms  stop
 If pulse width > 1.5 ms  rotate in one direction
 If pulse width < 1.5 ms  rotate in another direction
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Install IAR
 We will begin our labs next week
 Install the programming software ahead
 Go to www.ti.com
 Click Microcontroller
 In MSP430 menu, click Tools & Software
 Find IAR-KICKSTART and click on it
 Download software and install
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