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? Examples of why you want low-power solutions. Here are two wristwatches, one from IBM which runs Linux and one from Samsung which is the world’s smallest cellphone. It is voice-controlled and also works as a watch! Here are two prototype devices for helping blind people to see. The upper one is a system which converts visual data into sounds. The special glasses contain a miniature camera and the computer in the backpack convert the visual images into a sound picture which enable the wearer to see in a very useful way. In this example, the lady is able to pinpoint the location of her stick and pick it up purely by interpreting the sound signals she receives. Below is a more sophisticated and altogether more scary system. This one also builds a camera into a special pair of glasses but them feeds the signals directly into an implant in the visual cortex in the brain. I didn’t include the pictures of that bit because they made me a bit queasy! Finally, a research project which is currently going on at MIT in the States to build a complete wearable computing platform, complete with wireless connections, optical sensors and displays and so on. It doesn’t look up to much and you wouldn’t win any fashion awards in it but they do say that it looks very nice when built into a smart blue shirt.

Why Study Microprocessor Design? Sony Playstation 2000 (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!

Why Study Microprocessor Design? Wireless Sensor Networks Platform Power 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.

Microcontroller (MCU) 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? Mention the ubiquity of handheld devices and things that run on one battery

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 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!

Microprocessors are everywhere in 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 address data Memory location n-2 Memory location n-1 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 data address Register 1 r/w Register n-1 inst ALU CPU

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 System software 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 ELEC 330

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