microprocessor – intro! md. atiqur rahman ahad. introduction to microcontrollers parts of...
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Microprocessor – Intro!
Md. Atiqur Rahman Ahad
Introduction to Microcontrollers
Parts of computer: CPU, memory, I/O
• CPU: Control and data path
• Memory: Stores instruction and data
• Input/output: Interact with the outside of computers
Why Study Microprocessor Design?
Why Study Microprocessor Design?
° (as reported in Microprocessor Report, Vol 13, No. 5)• Emotion Engine: 6.2 GFLOPS, 75 million polygons per second
• Graphics Synthesizer: 2.4 Billion pixels per second
• Claim: Toy Story realism brought to games!
Sony Playstation 2000
Why Study Microprocessor Design?Wireless Sensor Networks PlatformPower Metering Application
Microcontrollers vs Microprocessors
• A microprocessor is a CPU on a single chip.
• If a microprocessor, its associated support circuitry, memory and peripheral I/O components are implemented on a single chip, it is a microcontroller.
What is an Embedded System?
• A combination of computer hardware and software, and perhaps additional mechanical or other parts, designed to perform a dedicated function.
• In some cases, embedded systems are part of a larger system or product, as is the case of an anti-lock braking system in a car. Contrast with general-purpose computer.
• Examples range from washing machines, cellular phones to missiles and space shuttles.
• Embedded Systems– Operations managed behind the scenes by a
microcontroller
• Microcontroller (MCU)– An integrated electronic computing device that
includes three major components on a single chip
• Microprocessor (MPU)
• Memory
• I/O (Input/Output) ports
What is an Embedded System?
• Electronic devices that incorporate a computer (usually a microprocessor) within their implementation.
• A computer is used in such devices primarily as a means to simplify the system design and to provide flexibility.
• Often the user of the device is not even aware that a computer is present.
Killer apps!
• Communications network routers, switches, hubs.
• Children’s toys • Fuel injection control, passenger environmental
controls, anti-lock braking systems, • Air bag controls, • GPS mapping.• Automotive Navigation systems, automatic landing
systems, flight attitude controls, • Engine controls, space exploration ……..
Where are the embedded devices?
• Instrumentations: Data collection, oscilloscopes, signal generators, signal analyzers, power supplies.
• Industrial: Elevator controls, surveillance systems, robots.
• Home: Dishwashers, microwave ovens, VCRs, televisions, stereos, fire/security alarm systems, lawn sprinkler controls, thermostats, cameras, clock radios, answering machines.
• Printers, scanners, keyboards, displays, modems, hard disk drives, CD-ROM drives.
Embedded Rocks!
• Embedded processors account for 100% of worldwide microprocessor production!
• Embedded:desktop = 100:1
• Embedded Systems is a big, fast growing industry
$ 40 billions in 2000
$92.0 billion in 2008
$112.5 billion (estimated) by the end of 2013• Embedded hardware was worth $89.8 billion in
2008 and is expected to reach $109.6 billion in 2013
• Embedded software generated $2.2 billion in 2008. This should increase to $2.9 billion in 2013
• Microprocessors/Microcontrollers are the core of embedded systems.
http://www.bccresearch.com/report/embedded-systems-technologies-markets-ift016c.html
Computer Technology Dramatic Change• Processor
– 2X in speed every 1.5 years; 100X performance in last decade
• Memory– DRAM capacity: 2X / 2 years; 64X size in last decade– Cost per bit: improves about 25% per year
• Disk– capacity: > 2X in size every 1.0 years– Cost per bit: improves about 100% per year– 250X size in last decade
Computer Technology Dramatic Change!
• State-of-the-art PC (at least…)
– Processor clock speed: 5000 MegaHertz (5.0 GigaHertz)
– Memory capacity: 4000 MegaBytes (4.0 GigaBytes)
– Disk capacity: 2000 GigaBytes (2.0 TeraBytes)
– New units! Mega => Giga, Giga => Tera
(Kilo, Mega, Giga, Tera, Peta, Exa, Zetta, Yotta = 1024)Kilo, Mega, etc. are incorrect Terminologies!
Microprocessorsare everywherein our life.
Microcontroller Components – Memory
• Each memory location has a specific address
• We must supply an address to access the corresponding location
• R/W allows us to select reading or writing
• Various types of memory for different functions and speeds
Memory location 0
Memory location 1
Memory location n-1
Memory location n-2
address data
r/w
Microcontroller Components – Memory
• Read Only Memory - Memory that can only be read– Holds the program code for a microprocessor used in an
embedded system where the code is always the same and is executed every time the system is switched on
– Computer BIOS, boot-up information• Other types of Read Only Memory
– Erasable Programmable Read Only Memory (EPROM) – Similar to ROM but can be erased (exposure to ultraviolet light) and reprogrammed
– Electrically Erasable Programmable Read Only Memory (EEPROM) – more common that EPROM because it can be erased by the microprocessor
– Flash Memory, Ferroelectric RAM (FRAM), Magnetic Random Access Memory (MRAM)
Microcontroller Components – Memory
• Random Access Memory – used to store dynamic data when processor is running– Holds program code and data during execution – Can be accesses in any random order – unlike takes or disks
• Some types of RAM– Static RAM (SRAM) – Uses transistors to store bits, fast SRAM is used
for cache – Dynamic RAM (DRAM) – Uses capacitors to store bits, must be
refreshed, smaller and cheaper than SRAM• Fast Page Mode (FPM), Extended Data Out (EDO)• Synchrounous DRAM (SDRAM) – introduced in 1997 and replaced most
DRAM in computers by 2000• Double Data Rate (DDR SDRAM) – uses both clock edges found today in
most computers• Direct Rambus DRAM (RDRAM) – somewhat of a flop
Microcontroller Components – CPU
• Smart part – Processes instructions and data– All the parts of a microprocessor
• Registers – fast memory used to store operands and other information– Condition register –
positive/negative result– Exception register – overflow
condition– Loop count register
• Load-store architecture
Register 0
Register 1
Register n-1
dataaddress
r/w
CPU
ALUinst
Microcontroller Components – I/O
• Connection to the outside world
• Examples– Analog to Digital Converter– Temperature Sensor– Display– Communications Circuit
Microcontroller Components – BUS
• Group of wires used to transport information• CPU to Memory
– Address bus– Data bus
• CPU to I/O– Port mapped I/O – used when address space is limited,
special instructions are needed for I/O– Memory mapped I/O – I/O looks like memory
locations, easier to use and common in Reduced Instruction Set Computing (RISC)
MPU-Based Systems
• System hardware– Discrete components
• Microprocessor, Memory, and I/O
– Components connected by buses• Address, Data, and Control
• System software– A group of programs that monitors the
functions of the entire system
MPU-Based Time and Temperature System
MCU-Based Systems
• Includes microprocessor, memory, I/O ports, and support devices (such as timers) on a single semiconductor chip
• Buses are generally not available to a system designer
• I/O ports are generally multiplexed and can be programmed to perform different functions
MCU-Based Time and Temperature System
Read -- Computer Architectures
• Princeton versus Harvard Architecture
• CISC versus RISC processors
• Microprocessors and Microcontrollers
Processor Performance
CPU Time
= # Cycles × Cycle Time
= # Instructions × CPI × Cycle Time
CPI: Cycles per instruction
Embedded System Programming
• Key factors in embedded programming– Speed – timing constraints, limited processing power– Code size – limited memory, power
• Programming methods– Machine Code – bits – Low level language – assembly– High level language – C, C++, Java– Application level language – Visual Basic, Access
• Levels of abstraction – factor out details to focus on few concepts at a time
Embedded System Programming
• Why use C in embedded programming?– Ease of management of large embedded projects
– Provides an additional level above assembly programming
– Fairly efficient
– Supports access to I/O
• Why use assembly?– High speed, low code size
– However, difficult to do a large project in assembly
• From various sources