presentation title here - · pdf fileoxygenation level of blood that is passing through it....

1

Case studies of applications of

MSP430

Atul Lele, Ramakrishna Reddy K,

MSP430 Design,

Texas Instruments India Pvt Ltd.

LECTURE - 9

17-10-2011

2

Outline of today’s session

• What have we learnt so far

• Agenda for this session

– Biomedical Applications

– Metering Applications

– Wireless Applications

• Wrap-Up

• Q&A

17-10-2011

What have we learnt so far

• Motivation for Low Power Embedded Systems

• MSP430 Architecture

• MSP430 families

• Programming MSP430 using Code Composer Studio (CCS)

• Interrupts and Low Power Modes (LPM)

• Peripherals – DMA

– LCD

– Interfacing LCD

4

Biomedical applications

Biomedical applications

• Therapeutic Instruments

– Takes certain action based on the measurements

– The Microcontrollers must satisfy the 0 defective parts

per million (DPPM) criteria

– Ex: Automated External Defibrillator (AED)

• Diagnostic Instruments

– Only measures a physiological parameter

– Ex: Thermometer, Blood Glucose Meter (BGM),

Cholesterol meters, Thermometer, Electrocardiogram

(ECG), Heart rate monitor, Pulsoximeter

Pulsoximeter

• The Pulsoximeter is a medical instrument for

monitoring the blood oxygenation of a patient

• By measuring the oxygen level and heart rate, the

instrument can sound an alarm if these drop

below a pre-determined level

• Especially useful for new born infants and during

surgery

Source: focus.ti.com/lit/an/slaa274a/slaa274a.pdf

Theory of Operation

• The calculation of the level of oxygenation of blood (SaO2) is based on

measuring the intensity of light that has been attenuated by body

tissue

• SaO2 is defined as the ratio of the level oxygenated Hemoglobin over

the total Hemoglobin level (oxygenated and depleted)

• Body tissue absorbs different amounts of light depending on the

oxygenation level of blood that is passing through it. This

characteristic is non-linear

SaO2 = HbO2

Total Hemoglobin


Theory of Operation (Continued)

Log(Iac,λ1) SaO2 α Log(Iac, λ2)

R = R ;

• Two different wavelengths of light are used such that

– λ1 which is absorbed by tissue in proportion to the amount of SaO2 Eg.

Red

– λ2 that is least absorbed by any tissue, Eg. Infra red (IR)

• Each source is turned on and measured alternately

• By using two different wavelengths, the mathematical complexity of

measurement can be reduced

Iac,λ1 – Current measured at the detector with first light source (λ1)

Iac,λ2 - Current measured at the detector with second light source (λ2)

Note: There are a DC and an AC component in the measurements. It is assumed that the DC component

is a result of the absorption by the body tissue and veins. The AC component is the result of the absorption

by the arteries


Pulsoximeter Block Diagram


System Operation

• The two LEDs are time multiplexed at 500 times per second The PIN diode is alternately excited by each LED light source

• The PIN diode signal is amplified by the built in operational amplifiers OA0 and OA1. The ADC12 samples the output of both amplifiers

• The samples are correctly sequenced by the ADC12 hardware and the MCU software separates the infra-red and the red components

• The SaO2 level and the heart rate are displayed on an LCD

• Apart from the MCU, LCD panel, sensor probe and four transistors, only passive components are needed for this design


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Metering applications

MSP430 in Metering applications

• Water meter

• Gas meter

• Automated Meter Reading (AMR)

• Advanced Metering Infrastructure (AMI)

• Heat Cost Allocation

• Energy meter (1-phase, 2-phase, 3-phase)

Energy Meter (E-Meter)

• An energy meter is a device that measures amount of electrical energy consumed

• The energy is measured in kilo-watt-hours (kWh)

• Energy is the product of instantaneous voltage and current over time E= v*i*t

Source: focus.ti.com/asia/download/TechDay09kr_Track1_2.pdf

Types of Energy Meters

• Electromechanical meters – Most commonly used meters today

– Operates by counting number of revolutions of an aluminium disc

– The aluminium disc rotates at a speed proportional to the power usage

– Reading of meter is done manually

– Limited accuracy

• Electronic meters – Extremely favorable metrology with absolutely no moving parts

– Uses microcontrollers, DSP processors or ASIC for the metrology

– Extremely accurate measurements with digital display

– Robust tamper protection

– Self-energy consumption is negligible

– Some of the latest meters have automatic meter reading (AMR)


Types of measurements

• Single phase measurement – Common in most residential complexes

– One voltage and one current

– Supports low to medium load

• Dual phase measurement – Not common

– Two voltage separated by 180 degrees

– Supports medium to large load

• Three phase measurement – Industrial, agricultural, urban residential

– Consists of 3 separate phases or wires to distribute AC current

– Each phase is 120 degrees out of phase with the others

– It is more efficient to transmit current via 3-phases that are out of phase than a single phase system

– Especially designed for applications that service large loads


Why choose MSP430?

• Low-power + High performance

• Modern 16-bit RISC CPU

• Up to 192KB Flash and up to 16KB RAM

• Powerful clock system: Up to 25MHz, <6μs clock start-up

• Powerful analog front-end to form a System-on-Chip (SoC)

• Intelligent peripherals that boost performance

• 0.1μA power down / 0.8μA standby mode

• Integrated LCD driver with charge pump to support up to

160 segments

• Embedded emulation


MSP430 for E-metering

• Powerful 16-bit A/D converter (SD16, SD16_A) – Programmable gain amplifier

– Supports differential input

• Multiple SD16/SD16_A for simultaneous sampling of voltage and current channels

• Hardware multiplier to support up to 32-bit x 32-bit multiply for better accuracy

• Multiple communication peripherals that support a variety of wired and wireless protocols

• Enables tamper detection (anti-tampering)

• Calculates a comprehensive set of parameters with the use of a CPU independent metrology engine (Embedded Signal Processor, ESP)


System-on-Chip (SoC) solution

• Single-chip solution in place

of multi-chip

• Interfaces to a variety of

current sensors

• Support for various

wired/wireless protocols

• Metrology engine in

Hardware/Software

Analog

Front

End

(AFE)

Hardware

Multiplier Metrology

LCD Driver

Communication

Peripherals

Display

Wired & wireless

interfaces

MSP430

Calibration

Sensors

Shunt/

Current Transformer/

Rogowski Coil


http://en.wikipedia.org/wiki/Rogowski_coil

http://en.wikipedia.org/wiki/Rogowski_coil

Voltage Sensor - Resistor

• Simple and extremely cheap

• Values of R1 and R2 chosen depending on Vmains and desired range for Vin to A/D

• No level shifter necessary for differential inputs

• Gain amplifier stage not required

110V/ 230V 60Hz or 50Hz Mains

i

R1

R2

Vin

to MSP430

R2

R1 + R2 Vin = Vmains


Vmains

Line

Neutral

Current Sensor - Shunt

• Commonly used current sensor

• Simple to design, based on Ohm’s law

• Inexpensive

• Always in micro-ohms range to support a wide dynamic range of currents

• No magnetic effects

• Absolutely no inherent phase shifts

• Can be used only with single phase measurement systems

110V/ 230V 60Hz or 50Hz Mains

imains RSh

Vin

to MSP430

Vin = imains RSh

• In almost all cases, resistance is not constant, stable or perfectly linear over temperature

• Limited accuracy, resistor tolerances a concern for high precision meters

• No electrical isolation provided

• Self-heating due to power dissipation is a concern, posing limitations


Vmains

Line

Line

Current Sensor – Current Transformer

(CT)

• Provides electrical isolation protecting the measuring device

• Current in secondary is proportional to current in primary.

• With zero losses, the secondary current is the primary current divided by N (number of turns on the core)

• Provides best accuracy

• Subject to internal phase shift that needs to be compensated

• Burden resistor (load) control the maximum input current to CT

• Load must never be disconnected from secondary when current is flowing at the primary


Line

Line

Phase error due to CT

• CT introduces additional phase shift between V and I

• Phase compensation needed is measured during

calibration time

• A simple FIR filter is used to provide this compensation


SD16 Overview

• MSP430FE42x &

MSP430FE42xA

• Multiple channels

• Single external

input per channel

• Up to 256 OSR

• 1MHz modulation

frequency


PGA = Programmable Gain Amplifier

SD16_A Overview

• MSP430F47x4

• Multiple channels

• 30kHz to 1.1MHz

modulation

frequency

• Modulation

frequency divider

• Up to 1024 OSR

• Temperature

sensor

• AVCC measure


Analog Input Range

Depends on

• VREF

• PGA gain setting

• Applies to all

inputs in a

channel & OSR

settings

Note: Diagram shows the differential input voltage VIN


VREF/2

GAINPGA VFSR =

Hardware Multiplier

• Ideal for energy calculation to multiply voltage and current

readings

• Signed and unsigned multiply

• Signed and unsigned multiply and accumulate (MAC)

• 16-bit HW multiplier

– supports 16×16 bits, 16×8 bits, 8×16 bits, 8×8 bits

• 32-bit HW multiplier

– supports in addition all combinations with 24-bit and 32-bit data

– supports fractional mode for operands

• DMA trigger available on devices with DMA module

• Available for all devices on MSP430 E-metering portfolio


MSP430 Communication peripherals

• Flexible on-chip synchronous and asynchronous interfaces

– Asynchronous UART, IrDA

– Synchronous SPI, I2C

• High speed protocols possible

– Up to 16 MHz frequency available

• Support for Smart metering

– Automatic Meter Reading (AMR)

– Advanced Metering Infrastructure (AMI)

– Power line communication (PLC)

– Radio Frequency communication

• Easy interface to wired and wireless devices


MSP430 E-meter Metrology Portfolio

ESP430

MSP430FE42x

MSP430FE42xA

MSP430FE42x2

No ESP430

MSP430F47xx

MSP430F471xx

Merits

1. Ease of use

2. Faster time to market

3. Comprehensive sets of results

De-merits

1. Limited flexibility

2. Limited set of communication peripherals

3. 8MHz CPU frequency

Merits

1. Flexibile metrology

2. Better control of accuracy

3. 16MHz CPU

4. Variety of communication peripherals

De-merits

1. Effort of implementation


MSP430 E-metering metrology engine

ESP430 • Embedded signal

processor present on all devices that have an “E” in its nomenclature

• Energy metrology engine running parallel to CPU activity

• Dedicated use of SD16s and Hardware multiplier

• Combines analog and digital signal processing

• Returns energy, power, voltage, current and power factor measurements


MSP430FE42x(A) Energy meter

Tamper

Detection



Tamper

Detection


Load current


Tamper

Detection


Load voltage


Tamper

Detection


Return current

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Wireless applications

MSP430 in Wireless applications

• Alarm system, smoke/fire detector

• Home control and automation

• Wireless asset tracking

• Wireless Sensor Networks (WSN) with

ChipCon (CC) RF interfaces

Wireless Sensing Application

C Gateway Repeater

CO Sensor Occupancy

Sensor

Door

Lock

Smoke

Alarm

Glass

Break

Sensor

Occupancy

Sensor

Smoke

Alarm

Repeater

Peer to Peer message

Message to

Access point

Message repeated

through range extenders

Access point

Range Extender

End Device

Key

Fob

CO Sensor Glass

Break

Sensor

Range can be extended through repeaters. The circles represent the RF

range of the gateways and the extended RF range of repeaters.

Source: Borrowed from Gill Instruments presentation on MSP430

Applications of Wireless Sensor Networks

(WSN)

Emergency response

Asset tracking

Manufacturing process flow

Wildlife habitats

Ubiquitous computing environments


Precision Agriculture

Saving watering and fertilizing expenses

Increasing crop yield

Improving fruit size

Timing crop ripeness to match best price in the market

Saving labor expenses by wireless automatic data collection

Crop specific researches

Basic Measurements: Leaf CO2 exchange rate & Leaf transpiration rate & temperature Air CO2 concentration Absolute air humidity Soil moisture Sap flow rate


Building Automation


Available Global Frequencies

Power and other restrictions apply to different regions

http://processors.wiki.ti.com/index.php/Low_Power_RF_Solutions_Workshop

Low Power Wireless Protocols

• Standards Based

– Wi-Fi

– Bluetooth

– ZigBee (standard, Pro, Z-Accel)

– 802.15.4 (MAC)

– RFID

– Wireless USB

– RF4CE • Proprietary

– 6LoWPan (IPv6 over 802.15 networks)

– SimpliciTI™

– BlueTooth LE

– WHART

– EnOcean

– OneNet

– Others …


Short-Range Wireless Communications

1000m

Headsets

PC Peripherals

PDA/Phone

Building Automation

Residential Control

Industrial

Tracking

Sensors

Home Automation / Security

Meter Reading

Data Rate

(bps) 100k 1M 10M 10k 1k

Range

100m

10m

1m

ZigBee/IEEE 802.15.4

PC Networking

Home Networking

Video Distribution

Wi-Fi/802.11

Proprietary Low Power Radio

Gaming

PC Peripherals

Audio

Meter Reading

Building Mgt.

Automotive

UWB


Network Topologies

STAR

MESH

PAN COORDINATOR

FULL-FUNCTION DEVICE

REDUCED-FUNCTION DEVICE

CLUSTER

TREE


Demo

• Wireless Sensor Network for Temperature

measurement

eZ430-RF2500

USB

Powered

Spy Bi-Wire &

UART Interface

MCU pins

accessible

2x LEDs

MSP430F2274

Button CC2500

Chip

Antenna

Emulation Removable

Target Board

eZ430-RF Emulator

• Supports all MSP430

Spy Bi-Wire devices – Compatible with original eZ430-F2013

and -T2012 target boards

• MSP430 Application UART – Allows communications from PC Virtual

COM port to MSP430 target

– Available in or out of a debug session

Detachable Target Board

• Separate emulator to

debug remotely

• Includes 2xAAA batteries

and expansion board

for instant deployment

• Easy interface to external

sensors and projects

• Separate target boards

orderable by 2Q 2008

MSP430 + LPW for Applications

• A perfect fit for low power

wireless solutions

– Designed for low power

– Simple connection through SPI

• Compatible with ALL

MSP430 devices

• Standard based protocols

(ZigBee / 802.15.4) and

proprietary stacks available

*transmitter only

MSP430 FG461x

F261x F241x

F23x/F24x

F22xx

F41x

Suggested Devices High End General Purpose Cost Efficient

CC2xxx (CC2420, CC2500, 2520, 2550*) 2.4GHz

CC1xxx (CC, 1100, 1150*, CC1101) <1GHz Low Power

Wireless

Z-Accel

• ZigBee Certified Network Processor solution

• MSP4302274 + CCZACC – Communicates over SPI or

UART

• Easy to Use: SimpleAPI – 10 API Calls

– Device configuration

– Binding of devices

– Sending and receiving data

MSP430 + CC2560 (Bluetooth)

• Integrates CC2560 and MSP430BT5190

• Pre-flashed eZ430-RF2560 SDK with MindTree’s Ethermind Bluetooth stack, serial port profile (SPP) and embedded sample applications running on FreeRTOS

• Interactive sample PC game for demonstration of Bluetooth use in a remote control application using accelerometer data

• Removable USB stick enclosure, 2 LEDs, 3 pushbuttons

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Wrap-Up

17-10-2011

52

Wrap-Up

• MSP430 in a Pulsoximeter

• MSP430 in a single-phase Energy meter

• MSP430 in Wireless Sensor Networks (WSN)

17-10-2011

53

References

• Few slides on the applications were borrowed

from Gill Instruments presentation on MSP430

• Processors wiki on TI LPRF solutions http://processors.wiki.ti.com/index.php/Low_Power_RF_Solutions_Workshop

• MSP430 for E-meter Kevin Yoon http://focus.ti.com/asia/download/TechDay09kr_Track1_2.pdf

• A Single-Chip Pulsoximeter Design Using the

MSP430, Vincent Chan, Steve Underwood, http://focus.ti.com/lit/an/slaa274a/slaa274a.pdf

17-10-2011

http://focus.ti.com/asia/download/TechDay09kr_Track1_2.pdf

http://focus.ti.com/lit/an/slaa274a/slaa274a.pdf

54 17-10-2011

presentation title here - · pdf fileoxygenation level of blood that is passing through it....

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