EL-GY 6483: REAL TIME EMBEDDED SYTEMS NYU TANDON SCHOOL OF ENGINEERING Spring 2025 1 EL-GY 6483: REAL TIME EMBEDDED SYTEMS • Instructor: • Professor Matthew Campisi • Office:

370 Jay Street, 8th Floor • Email:

[email protected] • Teaching Assistants: • TBD 2 Logistics • Class Meeting Times and Locations: • 370 Jay Street Rm. 202/ZOOM • Textbook – No required Text, but many reference

materials.. • Quizzes: • 2 Open Book

• Embedded Challenge Spring 2025 • TBD (More info discussed in class) 3 • Grading Policy • Exams 40% (20% each) • Homework (Given weekly) 20% • Embedded Challenge 40% 4 EMBEDDED SYSTEMS  EMBEDDED SYSTEMS 5  EMBEDDED SYSTEMS 6 What are Embedded Systems? • Anything that uses a microprocessor but isn’t a general-purpose computer

 Smartphones?  Set-top boxes  Televisions  Video Games  Refrigerators  Cars  Planes  Elevators  Remote Controls  Alarm Systems • The user “sees” a smart (special-purpose) system as opposed to the computer inside

the systems • “how does it do that?” • “it has a computer inside of it” • “oh, BTW, it does not or cannot run Windows or MacOS” • The end-user typically does not or cannot modify or upgrade the internals 7 What about this course? • Hardware • I/O, peripherals: sensors/actuators, memory, busses, devices, control

logic, interfacing hardware to software • Software

• Lots of C and assembly, device drivers, low-level real-time issues,

scheduling • Concurrency; interrupts • Software/Hardware interactions • Where is the best place to put functionality – hardware or software? • What are the costs: • Performance • Memory requirements (RAM and/or FLASH ROM) • Integration of hardware and software • Programming, logic design, architecture • Algorithms, mathematics and common sense 8 Careers in Embedded? • Automotive systems • Perhaps designing and developing “drive-by-wire” systems • Self-driving vehicles • Telecommunications • Medical Devices • Consumer electronics • Cellular phones, MP3 devices, integrated cellular/tablet • Set-top box and HDTV • Home and Internet appliances/ IOT • Your refrigerator will be on the internet more than you are! • Defense and weapons systems • Process control • Gasoline processing, chemical refinement • Automated manufacturing • Supervisory Control and Data Acquisition (SCADA) • Space communications

• Satellite communications 9 Goals of the Course • High-level Goals • Understand the scientific principles and concepts behind embedded systems • Obtain hands-on experience in programming embedded systems By the end of the course, you should be able to • Understand the “big ideas” in embedded systems • Obtain direct hands-on experience on both hardware and software elements

commonly used in embedded systems design • Understand the basics of embedded system application concepts such as signal

processing and feedback control • Understand and be able to discuss and communicate intelligently about: • Embedded processor architecture and programming • OS primitives for concurrency, timeouts, scheduling, communication and

synchronization 10 The Big Ideas • HW/SW Boundary • Non processor centric view of architecture • Bowels of the operating software • Specifically, basic real-time operation with interrupts • Concurrency • Real-world design • Performance vs. cost tradeoffs • Analyzability • How do you “know” that your drive-by-wire system will function correctly? • Application-level techniques • Signal processing, control theory • Semaphores, locks, atomic sections

11 What is an Embedded system? • An embedded system is a computer system with a dedicated function within a larger

mechanical or electrical system, often with real-time computing constraints. It

is embedded as part of a complete device often including hardware and mechanical

parts. Embedded systems control many devices in common use today. • Typically dedicated software (may be user customizable) • Often replaces previously electromechanical components • Often no “real” keyboard • Often limited display or no general purpose display device

However, every system is unique – there are always exceptions 12 CPU: An All-Too-Common View of Computing • Measured by: • Performance 13 An Advanced Computer Engineer’s View • Measured by: Performance • Compilers matter too… 14 An Enlightened Computer Engineer’s View • Measured by: Performance, Cost

• Compilers & OS matters 15 An Embedded Computer Designer’s View • Measured by: Cost, I/O connections, Memory Size,

Performance 16 An Embedded Control System Designer’s View • Measured by: Cost, Time to Market, Cost, Functionality, Cost

& Cost 17 Atmel | SMART SAM D21 Processor (ARM Cortex M0+) 18 Atmel | SMART SAM D21 Processor (ARM Cortex M0+) • Data sheet (All 1100 Pages!) 19 A Customer’s View • Reduced Cost • Increased Functionality • Improved Performance • Increased Overall Dependability 20 Why are Embedded Systems Different? Four General Categories of Embedded Systems 1. General Computing

• Applications similar to desktop computing, but in an embedded

package • Video games, set-top boxes, wearable computers, automatic tellers • Tablets, Phablets 2. Control Systems • Closed loop feedback control of real-time system • Vehicle engines, chemical processes, nuclear power, flight control 3. Signal Processing • Computations involving large data streams • Radar, Sonar, Video compression 4. Communication & Networking • Switching and information transmission • Telephone system, Internet • Wireless everything 21 Typical Embedded System Constraints • Small Size, Low Weight • Handheld electronics • Transportation applications weight costs money • Low Power • Battery power for 8+ hours (laptops often last only 2 hours) • Limited cooling may limit power even if AC power available • Harsh environment • Heat, vibration, shock • Power fluctuations, RF interference, lightning • Water, corrosion, physical abuse • Safety critical operation • Must function correctly • Must not function incorrectly • Extreme cost sensitivity • $0.05 adds up over 1,000,000 units 22 Embedded System Design World-View A complex set of tradeoffs: • Optimize for more than just speed

• Consider more than just the computer • Take into account more than just initial product design Multi-Discipline • Electronic Hardware • Software • Mechanical Hardware • Control Algorithms • Humans • Society/Institutions Multi-Phase • Requirements • Design • Manufacturing • Deployment • Logistics • Retirement Multi-Objective • Dependability • Affordability • Safety • Security • Scalability • Timeliness X X 23 Embedded System Designer Skill Set • Appreciation for multidisciplinary nature of design • Both hardware & software skills • Understanding of engineering beyond digital logic • Ability to take project from specification through production • Communication and Teamwork skills • Work with other disciplines, manufacturing, marketing • Work with customers to understand the real problem being solved • Make a good presentation; even better – write “trade rag” articles • And, by the way, technical skills too….. • Low-level: Microcontrollers, FPGA/ASIC, assembly language, A/D, D/A • High-Level: Object oriented design, C/C++, Real Time Operating Systems • Meta-level: Creative solutions to highly constrained problems • Likely in the future: Unified Modeling Language, embedded networks 24 25 Microprocessor or Microcontroller? 26 A Little History What is a computer?  One that computes; specifically: programmable electronic device that can

store, retrieve and process data (from Merriam-Webster Dictionary)  A computer is a machine that manipulates data according to a list of

instructions (from Wikipedia) Classifications of Computers:  Personal computers  Mainframes  Supercomputers  Dedicated controllers – Embedded controllers 27 MAINFRAMES  Massive amounts of memory  Use large data words – 64 bits or greater  Mostly used for military defense and large business data

processing  Examples: IBM 4381; Honeywell DPS8 28 Personal Computers  Any general-purpose computer  Intended to be operated directly by

an end user  Range from small microcomputers that

work with 4-bit words to PCs working

with 32-bit words or more  They contain a Processor – called

different names

 Microprocessor – built using Very- Large-Scale Integration technology;

the entire circuit is on a single chip  Central Processing Unit (CPU)  Microprocessor Unit (MPU) –

similar to CPU 29 Supercomputers  Fastest and most powerful mainframes  Contain multiple central processors (CPU)  Used for scientific applications and number

crunching  Now have petaflops performance –

FLoating-point Operations Per Second

(FLOPS)  Used to measure the speed of the

computer  Examples of special-purpose supercomputers:  Belle, Deep Blue, and Hydra, for playing chess

 GRAPE, for astrophysics and molecular

dynamics  Deep Crack, for breaking the DES cipher  MDGRAPE3, for protein structure computation 30 Microcontrollers – Embedded Systems  An embedded system is a special-purpose computer system

designed to perform one or a few dedicated functions often

with real-time  An integrated device which consists of multiple devices  Microprocessor(MPU)  Memory  I/O (Input/Output) ports  Often has its own dedicated software 31 A little about

Microprocessor-based Systems …. 32 Evolution  First came transistors  Integrated circuits  SSI (Small-Scale Integration) to ULSI  Very Large Scale Integration circuits (VLSI)  1 – Microprocessors (MPU)  Microcomputers (with CPU being a microprocessor)  Components: Memory, CPU, Peripherals (I/O)  2 – Microcontroller (MCU)  Microcomputers (with CPU being a microprocessor)  Many special function peripheral are integrated on a single

circuit  Types: General Purpose or Embedded System (with special

functionalities) 33 Microprocessor-Based Systems  Central Processing Unit

(CPU)  Memory  Input/Output (I/O) circuitry  Buses  Address bus  Data bus

 Control bus 34 35 Microprocessor-Based System with Buses:

Address, Data and Control 36 Microprocessor-Based Systems Microprocessor  The microprocessor (MPU) is a computing and logic device that

executes binary instructions in a sequence stored in memory  Characteristics:  General purpose central processing unit (CPU)  Binary  Register-based  Clock-driven  Programmable 37  The Evolution of CPUs 38 Transistors  Vacuum Tube: A device to control,

modify, and amplify electronic

signals  Then came Transistors  Designed by John Bardeen,

Will Shockley, and walter

Brattain – scientists at the Bell

Telephone Laboratories in

Murray Hill, New Jersey, 1947  In 1960, Jack Kilby and Robert

Noyce designed the first

integrated circuit (IC)  Fairchild company manufactured

logic gates 39 Integrated Circuits  Advances in

manufacturing allowed

packing more transistors

on a single chip  Transistors and

Integrated Circuits from

SSI(Small-Scale

Integration) to ULSI  Birth of a

microprocessor and its

revolutionary impact

40 Microprocessors  Noyce and Gordon Moore

started Intel  Intel designed the first

calculator  Intel designed the first

programmable calculator  Intel designed the first

microprocessor in 1971  Model 4004  4-bit; 2300 transistors,

640 bytes of memory,

108 KHz clock speed 41 First Processors  Intel released the 8086, a 16-bit microprocessor, in 1978  Motorola followed with the MC68000 as their 16-bit processor  The 16-bit processor works with 16 bit words rather than 8

bit words  Instructions executed faster  Provide single instructions for more complex instructions

such as multiply and divide  16-bit processors evolved into 32-bit processors  Intel released the 80386  Motorola released the MC 68020 42 Evolution of CPUs In 1965, Gordon Moore, co-founder of Intel, indicated that the number of transistors per square inch

on integrated circuits had doubled every year since the integrated circuit was invented. Moore

predicted that this trend would continue for the foreseeable future. 43 Evolution of CPUs  Intel®Core i7  Intel®Core i7-5960X Processor Extreme

Edition  20M Cache, up to 3.50 GHz  8 Cores, 16 Threads  64-bit Instruction Set 44 Microprocessor-based Systems Memory Types  R/W: Read/Write Memory; also called RAM  It is volatile (losses information as a power is removed)  Write means the processor can store information  Read means the processor can retrieve information from the memory  Acts like a Blackboard!  ROM: Read-Only Memory  It is typically non-volatile (permanent) – can be erasable  It is similar to a page from your textbook 45 Microprocessor-Based Systems Memory Classification 46 Microprocessor-Based Systems  Memory Classification Electronically Erasable PROM Onetime programmable • One transistor and capacitor to

store a bit • Leakage problems, requires

refreshing • Used for dynamic data/program

storage • Cheap & slow • 4/6 transistor to save a single bit • Volatile • Fast but expensive 47 Erasable ROMs • Masked Programmable ROM • Programmed by the manufacturer • Programmable ROM (PROM) • Can be programmed in the field via the programmer • Erasable Programmable ROM (EPOM) • Uses ultraviolet light to erase (through a quartz window) • OTP refers to One-Time Programmable • Electrically Erasable Programmable ROM (EEPROM) • Each program location can be individually erased • Expensive • Requires programmer • FLASH • Can be programmed in-circuit (in-system) • Easy to erase (no programmer) • Only one section can be erased/written at a time (typically 64 bytes at a

time) 48 Microprocessor-based Systems I/O Ports  The way the computer communicates with the outside world devices  I/O ports are connected to Peripherals  Peripherals are I/O devices  Input devices  Output devices  Examples  Printers and modems  Keyboard and mouse  Scanner  Universal Serial Bus (USB) 49 Microprocessor-based Systems BUS  The three components – MPU, memory, and I/O, are connected by a BUS  Address Bus  Consists of 16, 20, 24, or 32 parallel lines (wires) – unidirectional  These lines contain the address of the memory location to read or

written  Control Bus  Consists of 4 to 10 (or more) parallel signal lines  CPU sends signals along these lines to memory and to I/O ports  Examples: Memory Read, Memory Write, I/O Read, I/O Write  Data Bus  Consists of 8, 16, or 32 parallel lines  Bi-directional  Only one device at a time can have its outputs enabled  This requires the devices to have three-state output 50 Expanded Microprocessor-Based System  Note the direction

of the busses.  What is the width

of the address bus?  What is the value

of the Address bus

to access the first

register of the

R/WM? Remember: 111 1111 1111 = 2^11=2K 51 Now what about Microcontrollers??? 52 First Microcontrollers  IBM started using Intel processors in its PC  Intel started its 8042 and 8048 (8-bit microcontroller) –

using in printers  Apple Macintosh used Motorola 68000  In 1980 Intel abandoned microcontroller business  By 1989, Microchip was a major player in designing

microcontrollers  PIC: Peripheral Interface Controller 53 Embedded Controllers Software Characteristics  No operating systems  Execute a single program, tailored exactly to the controller hardware  Assembly language (vs. High-level language)  Not transportable, machine specific  Programmer needs to know CPU architecture  Speed  Program size  Uniqueness 54 Microcontroller Unit (MCU) Block Diagram  An integrated electronic computing

and logic device that includes three

major components on a single chip  Microprocessor  Memory  I/O ports  Includes support devices  Timers  A/D converter  Serial I/O  Parallel Slave Port  All components connected by common

communication lines called the system

bus 55 MCU Architecture  RISC (Harvard)  Reduced instruction set computer  Simple operations  Simple addressing modes  Longer compiled program but faster to execute  Uses pipelining  CISC (Von Neuman)  Complex instruction set computer  More complex instructions (closer to high-level language

support) Bench marks: How to compare MCUs together MIPS: Million Instructions / second (Useful when the compilers are the same) 56 Main 8-bit Controllers  Microchip -PIC® Microcontrollers  RISC architecture (reduced instruction set computer)  Has sold over 2 billion as of 2002  Cost effective and rich in peripherals  Motorola – now Freescale  CISC architecture  Has hundreds of instructions  Examples: 68HC05, 68HC08, 68HC11  Intel – now Marvell  CISC architecture  Has hundreds of instructions  Examples: 8051, 8052  Many different manufacturerers: Philips, Dallas/MAXIM

Semiconductor, etc.  Atmel  RISC architecture (reduced instruction set computer)  Cost effective and rich in peripherals  AVR 57 Software: From Machine to

High-Level Languages (1 of 3)  Machine Language: binary instructions  All programs are converted into the

machine language of a processor for

execution  Difficult to decipher and write  Prone to cause many errors in writing High-Level Language Assembly Language Machine Language 58 Software: From Machine to

High-Level Languages (2 of 3)  Assembly Language: machine

instructions represented in

mnemonics  Has one-to-one correspondence with

machine instructions  Efficient in execution and use of

memory; machine-specific and not

easy to troubleshoot High-Level Language Assembly Language Machine Language 59 Software: From Machine to

High-Level Languages (3 of 3)  High-Level Languages: Such as

BASIC, C, and C++  Written in statements of spoken

languages (such as English)  Machine independent  Easy to write and troubleshoot

 Requires large memory and less

efficient in execution High-Level Language Assembly Language Machine Language 60  Data Format (8-bit) (1 of 4)  Unsigned Byte: All eight bits (Bit0

to Bit7) represent the magnitude

of a number

 Range 0 to FF in Hex and 0 to 255 in

decimal

Unsigned Signed 61  Data Format (8-bit) (2 of 4)  Signed Byte: Seven bits (Bit0 to Bit6)

represent the magnitude of a number  The eighth bit (Bit7) represents the sign of the

number. The number is positive when Bit7 is zero and

negative when Bit7 is one.  Positive Numbers: 0 to 7F (0 to 127)  Negative Numbers: 80 to FF (-1 to -128)  All negative numbers are represented in 2’s

compliment Unsigned Signed 62  Data Format (8-bit) (3 of 4)  Binary Coded Decimal Numbers (BCD)  8 bits of a number divided into groups of four, and

each group represents a decimal digit from 0 to 9  Four-bit combinations from A through F in Hex are

invalid in BCD  Example:

0010 0101 represents the binary coding of

the decimal number 25d which is different in value

from 25H 63  Data Format (8-bit) (4 of 4)  American Standard Code for Information

Interchange (ASCII)  Seven-bit alphanumeric code with 128 combinations (00 to FF)  Represents English alphabet, decimal digits from 0 to 9, symbols, and

commands 64 Storing Bits in Memory  We can store in different memory types  EEPROM, FLASH, RAM, etc.  In an 8-bit RAM  Each byte is stored in a single

memory register  Each word is stored in two memory

locations (registers)  DATA 0x1234  0x12 REG11 (High-order byte)  0001 0010  0x34REG10 (Low-order byte)  0011 0100 Remember: -8 -> 111 1000 (in two’s complement)

65 Design Examples ….. Microcontrollers vs. Microprocessors 66 MPU-Based Time and Temperature System

67 MCU-Based Time and Temperature System

68 51作业君版权所有