MCU Microcontroller Unit 1 MCU 1 cip or

MCU – Microcontroller Unit – 1 MCU 1 cip or VLSI core – applicationspecific Md. Atiqur Rahman Ahad

• We use more number of microcontrollers compared to microprocessors. • Microprocessors are primarily used for computational purpose, whereas microcontrollers find wide application in devices needing real time processing / control. • Embedded system: is a system whose principal function is not computational, but which is controlled by a computer embedded within it.

• The microprocessor is a processor on one silicon chip. • The microcontrollers are used in embedded computing. • The microcontroller is a microprocessor with added circuitry.

? ? ? • • Processor? Microprocessor? Microcomputer? Microcontroller? Embedded system? Sensor? What is inside a calculator? Smartphone? i. Pad? Laptop? Desktop PC? Supercomputer? Clustered computing system?

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 antilock 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.

Where are the embedded devices?

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 ……. .

Appli. • 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.

Appli! • Application of microcontrollers are numerous. – Domestic applications such as in washing machines, TVs, air-conditioners, – Automobiles, process control industries, cell phones, electrical drives, robotics and in space applications. – Biomedical instruments – Communication systems – Controller, Control systems – Instrumentations, etc.

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-ift 016 c. html

Examples: Refrigerator

Examples: Car Door

Examples: Derbot Autonomous Guided Vehicle

Examples: Derbot Autonomous Guided Vehicle

Microcontrollers

• How to convert a microcomputer into a microcontroller?

Microcontroller Packaging and Appearance From left to right: PIC 12 F 508, PIC 16 F 84 A, PIC 16 C 72, Motorola 68 HC 05 B 16, PIC 16 F 877, Motorola 68000 Some slides above are from - Dr. Gheith Abandah

Types of MCU – 8/16/32 -bit mcu – internal bus & instruction size, ALU – Instruction sets – RISC/CISC • Complicated instruction set comp [CISC] – It has an instruction set that supports many addressing modes. – It offers flexibility in choosing various ways of performing the data transfer and ALU ops. • Reduced ISC [RISC] – Supports 1/2 addressing modes – Need many registers – so need less fetching from external memories for operations… so higher performance in computing than CISC… e. g. , ARM

Types of MCU – Memory architecture • Harvard mem has a distinct mem address space for i. Program mem & ii. Data mem It has separate instructions , hence separate control signal[s], for data transfers from these two memories. • Princeton mem has a common mem space for both. So no need for separate …

Types of MCU – Family • 8051 – – – • • • Intel Philips Atmel Siemens Dallas Motorola PIC - Peripheral Interface Controller Hitachi Texas ARM - Advanced RISC Machine (previously known as Acorn RISC Machine) • Others

Microcontrollers • Microcontroller (MCU) – An integrated electronic computing device that includes three major components on a single chip • Microprocessor (MPU) • Memory • I/O (Input/Output) ports

Microcontrollers • Support Devices – Timers – A/D converter – Serial I/O • Common communication lines – System Bus

Block Diagram of Microcontroller

Microprocessor (MPU) • MPU (CPU) – Read instructions – Process binary data

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 address Register 0 Register 1 r/w Register n-1 data inst ALU CPU

Microcontroller Components – I/O • Connection to the outside world • Input Devices – Switches and Keypads – Provide binary information to the MPU • Output devices – LEDs and LCDs – Receive binary information from the MPU • 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

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

Microprocessor-Based Systems

MPU-Based Time and Temperature System

MCU-Based Time and Temperature System

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