Basics of Embedded Systems
IAX0230
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Course Organisation
Prof. Dr. Kalle Tammemäe
Prof. Dr.-Ing. Thomas Hollstein
Dr. Uljana Reinsalu
Goals
© Uljana Reinsalu, Thomas Hollstein
• The course is intended for Bachelorlevel students to get theoretical and
practical knowledge on embedded
systems (ES) design and
implementation
3
Organization/Contacts
•
Lecture:
 Prof. Dr. Kalle Tammemäe
[email protected], phone: 620-2260
room: ICT-528
 Prof. Dr.-Ing. Thomas Hollstein
[email protected], phone: 620-2260
room: ICT-528
© Uljana Reinsalu, Thomas Hollstein
 Dr. Uljana Reinsalu
[email protected], phone: 620-2259
room: ICT-520
•
Labs:
 Siavoosh Payandeh Azad, MSc
[email protected], phone: 620-2267
room: ICT-522
 Mairo Leier, PhD
[email protected], phone: 620-2265
room: ICT-512
 Dr. Uljana Reinsalu
4
© Uljana Reinsalu, Thomas Hollstein
ES on Moodle
Moodle Enrollment
Key:
5
Course-internal Communication
© Uljana Reinsalu, Thomas Hollstein
1. Moodle: Please update your data in
Moodle (with picture – helps to learn
the names)
2. E-Mail: [email protected]
All your mail’s subjects start with:
“ES:” <your subject>
Please send today an E-Mail with the following
content:
FIRST NAME: <e.g. Toomas Hendrik>
FAMILY NAME: < e.g. Ilves>
STUDENT-ID: <e.g. 08154711 IASM>
MOBILE: <your mobile phone number>
EMAIL: <your email-address>
6
Course Structure
© Uljana Reinsalu, Thomas Hollstein
•
•
•
•
5 ECTS
32 hours lectures
32 hours labs
62 hours individual work




Reading of course material
Planning labs and writing lab reports
Preparation for examinations
Communication with tutors and other
students
7
© Uljana Reinsalu, Thomas Hollstein
Lecture Content
1. Pre-course test and Introduction (lecture)
2. Introduction to Microcontrollers
3. Introduction to ARM Cortex-M Processors
4. Microcontroller Input/Output
5. Modular Programming and Debugging
6. Microcontroller programming in C
7. Serial and Parallel Port Interfacing
8. Sensors and Actuators
9. Midsemester exam !!!
10. Interrupt Programming
11. Analog I/O Interfacing
12. HW/SW Synchronization (semaphores?)
13. Low-Power Design of Embedded Systems
14. Time Interfacing
15. Advanced Serial Interfacing (USB, WiFi)
16. Advanced topics
8
Labs
© Uljana Reinsalu, Thomas Hollstein
Main supported platform:
ARM Cortex-M
Microcontroller Based System
• ARM® Cortex®-M4F Based
MCU TM4C123G LaunchPad™
Evaluation Kit
Unsupported alternative:
TI microcontroller-based
Embedded System Design
•
MSP430F5529 USB LaunchPad
Evaluation Kit
Lab room: ICT-502A/B
Source: TI
9
Assessment
Final exam
• Labs:
 11 labs reported and defended
• Mid-term written exam
• Final written examination
Labs
40%
40%
20%
Midterm Exam
• Prerequisites for midterm exam:
© Uljana Reinsalu, Thomas Hollstein
 5 labs for midterm
• Prerequisites for final:
 Midterm exam (positive)
 11 labs (= 100%)
• Final grade = exam grade – # of missing labs(!)
10
Course book + additional reading
© Uljana Reinsalu, Thomas Hollstein
• Jonathan W Valvano, Embedded Systems:
Introduction to Arm® CortexTM-M
Microcontrollers , Fifth Edition (Volume 1) 5th
Edition, 2015 (3rd printing), ISBN-10:
1477508996 | ISBN-13: 978-1477508992
http://users.ece.utexas.edu/~valvano/arm/
• Marwedel „Embedded Systems Design“
• Wayne Wolf „Computers as Components.
Principles of Embedded Computing System
Design“
• Elecia White „Making Embedded Systems“
• Kopetz „Real-Time Systems“
• E. A. Lee, S. A. Seshia „Introducation to
Embedded Systems: A cyber-physical
systems approach“
11
Basics of Embedded Systems
© Uljana Reinsalu, Thomas Hollstein
IAX0230
Introduction
Prof. Kalle Tammemäe
Prof. Dr.-Ing. Thomas Hollstein
Dr. Uljana Reinsalu
What is an Embedded System?
Definition: Embedded systems (ES) are
information processing systems embedded
into enclosing products. [Marwedel, 2003]
© Uljana Reinsalu, Thomas Hollstein
Main reason for buying is not information processing
Embedded software is software
integrated with physical processes. The
technical problem is managing time and
concurrency in computational systems.
[Lee, 2006]
Definition: Cyber-Physical Systems
(CPS) are networked integrations of
computation and physical processes.
13
© Uljana Reinsalu, Thomas Hollstein
Examples of embedded systems
•
•
•
•
•
•
•
•
Cars
Avionics
House control systems
Military
Consumer electronics
Health care systems
Production systems
etc.
Source: auto123.com
Source: www.robotplatform.com
Source: retis.sssup.it
14
Example structure of embedded
system
•
•
•
•
Dedicated towards certain application
Communicates with environment
May have human interface
Usually is a part of a bigger system
© Uljana Reinsalu, Thomas Hollstein
Human interface
sensors
Network
fabric
Information
processing
actuators
environment
15
Embedded systems importance
© Uljana Reinsalu, Thomas Hollstein
2001 National Research Council Report:
“Information technology (IT) is on the verge of another
revolution. Driven by the increasing capabilities and ever
declining costs of computing and communications
devices, IT is being embedded into a growing range of
physical devices linked together through networks and
will become ever more pervasive as the component
technologies become smaller, faster, and cheaper…These
networked systems of embedded computers… have the
potential to change radically the way people interact with
their environment by linking together a range of devices
and sensors that will allow information to be collected,
shared, and processed in unprecedented ways… The use
of [these embedded computers] throughout society could
well dwarf previous milestones in the information
revolution.”
16
© Uljana Reinsalu, Thomas Hollstein
Embedded systems importance
• 4 billions of users of mobile phones at
2013, 5 billions at 2019 [statista.com]
• 403 million global smartphones sale in
fourth quarter of 2015 [gartner.com]
• More smart phones are sold worldwide
than PCs at 2011 [www.infacts.biz]
• Electronics makes more than 25% of
todays car price. [EE Times 2010],
some high-end cars contain more than
100 processors.
• The year profit of home healthcare
systems at 2011 is ca. 225 mln. USD
(2006 – 70 mln.)[www.itfacts.biz]
17
© Uljana Reinsalu, Thomas Hollstein
Examples of embedded systems
In Cars:
• ABS: anti-lock breaking systems
• ESP: electronic stability control
• Air bag control systems
• Engine control systems
• Air condition
control systems
• Anti-theft
protection
• Parking assistance
• Collision avoidance
• Adaptive cruise control, etc.
Source: iec.org
18
Examples of embedded systems
© Uljana Reinsalu, Thomas Hollstein
In Avionics:
• Flight control systems
• Anti-collision systems
• Pilot information systems
• Entertainment systems
• Others
 Dependability is of utmost importance
Source: retis.sssup.it
19
Examples of embedded systems
© Uljana Reinsalu, Thomas Hollstein
In Consumer electronics:
• MP3 audio
• Digital camera
• Home electronics: washing machine,
microwave etc.
• Game consoles
Source: www.sciencedirect.com
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Examples of embedded systems
In information systems:
• Mobile phones
• End-user equipment
• Routers and digiboxes
• Wireless LAN
• others
© Uljana Reinsalu, Thomas Hollstein
Source: www.ccartoday.com
Source: www.techspot.com
21
Examples of embedded systems
© Uljana Reinsalu, Thomas Hollstein
In fabrication equipment:
Controlling the valve
Source: P. Marwedel: Embedded System Design
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Industry 4.0
Source: www.seas.upenn.edu
Industry Automation based on
Cyber-Physical Systems
Control Systems
© Uljana Reinsalu, Thomas Hollstein
Assembly line
Loom
4th Revolution:
driven by
Networks / cyberspace
3rd Revolution:
driven by
electronics & computers
2nd Revolution:
driven by
electrical power
1st Revolution:
driven by
water & steam power
1784
1870
1970
2000
23
© Uljana Reinsalu, Thomas Hollstein
Internet of Things
•
•
Uniquely identifiable objects, having communicating
virtual representations in the internet
New SmartX services for the convenient organisation
of live, work, cities, energy supply, services, …
24
© Uljana Reinsalu, Thomas Hollstein
Examples of embedded systems
In:
• Smart buildings
• Robotics
• Health care
• Logistics
• Security
• Railways
• Military
• Etc.
25
Characteristics of embedded
systems
© Uljana Reinsalu, Thomas Hollstein
Must be efficient:
1. Energy efficient
2. Run-time efficient
3. Code size efficient
4. Weight efficient
5. Cost efficient
Dedicated towards a certain application.
Knowledge about behavior at design time
can be used to minimize resources and to
maximize robustness
Dedicated user-interface: push-buttons,
steering wheels, pedals etc.
26
© Uljana Reinsalu, Thomas Hollstein
Characteristics of embedded
systems (2)
Many ES must meet real-time constraints:
• A real-time system must react to stimuli
from the controlled object (or the operator)
within the time interval dictated by the
environment.
• For real-time systems, right answers arriving
too late are wrong
• A time-constraint is called hard if not
meeting that constraint could result in a
catastrophe [Kopetz, 1997]
• All other time constraints are soft
• A guaranteed system response has to be
explained without statistical arguments 27
© Uljana Reinsalu, Thomas Hollstein
Characteristics of embedded
systems (3)
• Frequently connected to the physical
environment through sensors, actuators
• Many ES are Hybrid systems (analog
and digital parts)
• Typically, ES are reactive systems
A reactive system is one that is in
continual interaction with its environment
and executes at a pace determined by the
environment. [Bergé, 1995]
• Behavior depends on input and current
state -> automata model is often
appropriate
28
© Uljana Reinsalu, Thomas Hollstein
Characteristics of embedded
systems (4)
Must be dependable:
1. Reliability: the probability that a
system will not fail
2. Maintainability: probability that a
failing system can be repaired within a
certain time-frame
3. Availability: probability that the
system is available
4. Safety: no harm to be caused
5. Security: confidential and authentic
communication
29
Characteristics of embedded
systems (5)
© Uljana Reinsalu, Thomas Hollstein
Even perfectly designed systems can fail if
the assumptions about the workload and
possible errors turn out to be wrong.
[Kopetz, 1997]
Making the system dependable must not
be an after-thought, it must be considered
from the very beginning. [Kopetz, 1997]
30
Challenges in Embedded Systems
Design
Dynamic environment
Must meet real-time constraints
Profoundly concurrent
How to validate real-time embedded
software
• HW/SW co-design
• Efficient implementation
© Uljana Reinsalu, Thomas Hollstein
•
•
•
•
31
Iterative design process
© Uljana Reinsalu, Thomas Hollstein
• Model specify what system does
• Design specify how system does what it does
• Analysis specify why a system does what is does
32
Simplified design flow
application
knowledge
© Uljana Reinsalu, Thomas Hollstein
specification
HW-components
design repository
design
application
mapping
test
optimization
System software
(RTOS, ..)
evaluation & validation
test
33
© Uljana Reinsalu, Thomas Hollstein
Goals
• Getting practical experience with
embedded microcontrollers (SW
programming with close HW
relation)
• Issues: timing (real-time), I/O
handling, power efficiency,
dependability
34
What is a Microcontroller???
© Uljana Reinsalu, Thomas Hollstein
Microprocessor
+ RAM
+ Flash Memory (non-volatile)
+ Timers
+ I/O (digital and analog)
+ Communication (eg. UART,
Wireless)
35
Source: Atmel.com
MSP430g2553
© Uljana Reinsalu, Thomas Hollstein
UART
(mini USB)
Analog
(ADC)
inputs
Buttons
36
Microcontrol
ler
GPIO
Design Flow/Tool Flow (Code
Composer)
© Uljana Reinsalu, Thomas Hollstein
• Link to TI resourses:
http://www.ti.com/ww/en/launchpa
d/launchpads-msp430-mspexp430g2.html#tabs
37
© Uljana Reinsalu, Thomas Hollstein
How to use Datasheets
MSP430 User guide
MSP430 datasheet
• Functional diagram
• Pin description
• Description: read thoroughly
• Operational modes
• Application examples
• Concrete section of your current
interest
38
Memory-mapped I/O for MSP430
© Uljana Reinsalu, Thomas Hollstein
• ...picture
The MSP430
von-Neumann
architecture
has one address space
shared with:
-SFRs
-peripherals
-RAM
-Flash/ROM memory
The addressible
memory space is
128 KB
39
Microcontroller Program Structure
© Uljana Reinsalu, Thomas Hollstein
#include <msp430g2553.h>
unsigned int i = 0;
void main(void)
{
WDTCTL = WDTPW + WDTHOLD;
// Stop watchdog timer.
// P1DIR is a register that configures the direction (DIR) of a port pin as an output or an input.
P1DIR |= 0x01;
// To set a specific pin as output or input, we write a '1' or '0' on the appropriate bit of the
register.
// P1DIR = <PIN7><PIN6><PIN5><PIN4><PIN3><PIN2><PIN1><PIN0>
// Since we want to blink the on-board red LED, we want to set the direction of Port 1, Pin 0
(P1.0) as an output
for (;;)
{
P1OUT ^= 0x01;
// Toggle P1.0 using exclusive-OR operation (^=)
// P1OUT is another register which holds the status of the LED.
// '1' specifies that it's ON or HIGH, while '0' specifies that it's OFF or LOW
for(i=0; i< 20000; i++);
// Delay between LED toggles. This for-loop will run until the condition is met.
}
}
40
Labs Overview
© Uljana Reinsalu, Thomas Hollstein
• 5 introductory labs:
1. Introduction to board and tools;
blinking LEDs application
2. Use internal Timers to generate
delay; using debugging equipement
3. Using UART; reading inputs with
interrups and polling; SPI; I2C
4. Reading processor temperature,
generating PWM signal; motor
control
5. Power management
41
© Uljana Reinsalu, Thomas Hollstein
Achieved Skills
• Microcontroller programming using
C with close HW relation
• Toolchain usage
• Design embedded system with
off-the-shelf components
• Understanding the manuals
• Lab equipment usage
42
Basics of Embedded Systems
IAX0s30
Click to edit Master title style
Basics: Binary Numbers and
Operations
Prof. Dr. Kalle Tammemäe
Dr. Uljana Reinsalu
Prof. Dr.-Ing. Thomas Hollstein
Microcontrollers: Number Systems
• Decimal:
 Digits 0..9
 578 = 5*102 + 7*101 + 8*100
• Binary:
© Uljana Reinsalu, Thomas Hollstein
 Digits 0..1
 578D = 512 + 64 + 2 = 0010 0100 0010B
• Hexadecimal:
 Digits 0..F
(10D=A, 11D=B,...,15D=F)
 578D = 0010 0100 0010B
2
4
2H
= 2*162 + 4*161 + 2*160
44
Microcontrollers: Number Systems
• Octal:
 Digits 0..7
 578D = 001 001 000 010B
1
1
0
2O
© Uljana Reinsalu, Thomas Hollstein
= 1*83 +1*82 + 0*81 + 2*80
• Conversion Dec2Hex:
578/16 = 36
36/16 = 2
2/16 = 0
Remainder: 2
Remainder: 4
Remainder: 2
242H
45
Microcontrollers: Arithmetics
© Uljana Reinsalu, Thomas Hollstein
Subtraction
46
Microcontrollers: 2‘s Complement
© Uljana Reinsalu, Thomas Hollstein
• 2K:
37D =
127D =
00100101B
11011010B (Bit complement)
+1B
-------------11011011B = -37D
01111111B
10000000B
+1B
-------------10000001B = -127D
47
Microcontrollers: 2‘s Complement
• 2K:
© Uljana Reinsalu, Thomas Hollstein
0D =
-128D =
Overflow: sign bit
changed
00000000B
11111111B (Bit complement)
+1B
-------------100000000B = 0D
10000000B
01111111B
+1B
-------------10000000B = -128D
48
© Uljana Reinsalu, Thomas Hollstein
Microcontrollers: Signed Arithmetics
49
Microcontrollers: Arithmetics
Fixed-point arithmethics:
Sign bit
23 22 21 20 2-1 2-2 2-3
© Uljana Reinsalu, Thomas Hollstein
Decimal point
• After multiplication and division operations
normalizing shift operations are required
• Multiplications/Divisions can be dangerous,
since result could be rounded to 0
50
Setting one Bit in a Control Register
• How to set one bit in a Register to 1:
© Uljana Reinsalu, Thomas Hollstein
Original Register Content:
1 0 1 1 0 1 1 1
Operator:
Bitwise OR
Bit Mask:
0 0 0 0 1 0 0 0
Final Register Content:
1 0 1 1 1 1 1 1
51
Clearing one Bit in a Control Register
• How to set one bit in a Register to 0:
Original Register Content:
© Uljana Reinsalu, Thomas Hollstein
Operator:
1 0 1 1 0 1 1 1
Bitwise AND
Bit Mask:
1 1 1 1 1 1 0 1
Final Register Content:
1 0 1 1 0 1 0 1
52
Toggling one Bit in a Control Register
• How to toggle an individual bit in a
Register:
Original Register Content:
© Uljana Reinsalu, Thomas Hollstein
Operator:
1 0 1 1 0 1 1 1
Bitwise XOR
Bit Mask:
0 0 0 1 0 0 0 0
Final Register Content:
1 0 1 0 0 1 1 1
53
Bitwise Clear in a Register
© Uljana Reinsalu, Thomas Hollstein
• Clearing bits in Register according to
control bits:
Original Register Content:
1 0 1 1 0 1 1 1
Operator:
BIC (bitwise Clear)
Control:
1 0 0 1 1 0 1 0
Final Register Content:
0 0 1 0 0 1 0 1
54