01. Embedded Systems

TRUE

(TRUE or FALSE) Computer systems are everywhere.

Embedded system

It is nearly any computing system other than a desktop, laptop, or mainframe computer.

consumer electronics, house appliances, office automation, business equipment, automobiles

Where are embedded systems found? (HINT: CHOBA)

consumer electronics

cellphones, pagers, digital cameras, camcorders, videocassette recorders, portable video games, calculators, and personal digital assistants

home appliances

microwave ovens, answering machines, thermostat, home security, washing machines, and lighting systems

office automation

fax machines, copiers, printers, and scanners

business equipment

cash registers, curbside check-in, alarm systems, card readers, product scanners, and automated teller machines

automobiles

transmission control, cruise control, fuel injection, anti-lock brakes, and active suspension

single-functioned, tightly constrained, reactive and real-time

What are the common characteristics of embedded systems? (HINT: STR)

single-functioned

It is a characteristic in which an embedded system usually executes only one program, repeatedly.

TRUE

(TRUE or FALSE) A pager is single-functioned.

FALSE. A desktop system executes a variety of programs, like spreadsheets, word processors, and video games, with new programs added frequently.

(TRUE or FALSE) A desktop system is single-functioned.

TRUE

(TRUE or FALSE) All computing systems have constraints on design metrics, but those on embedded systems can be especially tight.

design metric

It is a measure of an implementation’s features, such as cost, size, performance, and power.

Reactive and real-time

Many embedded systems must continually react to changes in the system’s environment, and must compute certain results in real time without delay.

TRUE

(TRUE or FALSE) A delayed result could result in a failure to maintain the system’s control.

A2D and D2A

They convert analog images to digital and digital to analog, respectively.

Charge-coupled Device preprocessor

CCD preprocessor meaning?

JPEG codec

It compresses and decompresses an image using the JPEG compression standard, enabling compact storage in the limited memory of the camera.

Pixel coprocessor

It aids in rapidly displaying images.

Memory controller

This controls access to a memory chip also found in the camera.

DMA controller

It enables direct memory access without requiring the use of the microcontroller.

UART

It enables communication with a PC’s serial port for uploading video frames.

ISA bus interface

It enables a faster connection with a PC’s ISA bus.

LCD ctrl and Display ctrl

They control the display of images on the camera’s liquid-crystal display device.

Multiplier/Accum

This assists with certain digital signal processing.

microcontroller

At the heart of the system, this is a processor that controls the activities of all the other circuits.

microcontroller

This is a more general processor designed for general tasks.

design metric competition

“Decreasing one may increase others.”

design metric

It is a measurable feature of a system’s implementation.

unit cost

It is the monetary cost of manufacturing each copy of the system, excluding NRE cost.

Non-Recurring Engineering cost

What does NRE in NRE cost stand for?

NRE cost

The monetary cost of designing the system. Once the system is designed, any number of units can be manufactured without incurring any additional design cost.

\
One-time monetary cost of designing the system.

size

It is the physical space required by the system, often measured in bytes for software, and gates or transistors for hardware.

bytes

size measurement in a software?

gates or transistors

size measurement in a hardware

performance

The execution time or throughput of the system.

power

The amount of power consumed by the system, which determines the lifetime of a battery, or the cooling requirements of the IC, since more power means more heat.

TRUE

(TRUE or FALSE) More power means more heat.

flexibility

It is the ability to change the functionality of the system without incurring heavy NRE cost. Software is typically considered very flexible.

TRUE

(TRUE or FALSE) Software is typically considered very flexible.

Time-to-market

The amount of time required to design and manufacture the system to the point the system can be sold to customers.

Time-to-prototype

The amount of time to build a working version of the system, which may be bigger or more expensive than the final system implementation, but can be used to verify the system’s usefulness and correctness and to refine the system’s functionality.

Maintainability

The ability to modify the system after its initial release.

correctness

Our confidence that we have implemented the system’s functionality correctly. We can check the functionality throughout the process of designing the system, and we can insert test circuitry to check that manufacturing was correct.

test circuitry

What is used to check if the manufacturing was correct?

safety

The probability that the system will not cause harm.

unit cost, NRE cost, size, performance, power, flexibility, time-to-market, time-to-prototype, correctness, and safety + maintainability

What are the 10 design metrics? (HINT: UNSPPFTTCS + M)

TRUE

(TRUE or FALSE) The design metrics typically compete with one another: improving one often leads to a degradation in another (a wheel with numerous pins).

TRUE

(TRUE or FALSE) To best meet the optimization challenge, the designer must be comfortable with a variety of hardware and software implementation technologies, and must be able to mitigate form one technology to another, in order to find the best implementation for a given application and constraints. Thus, t**he designer must be an expert in both areas (hardware and software).**

Semiconductor Industry Association

What association said that the rate at which designers can produce transistors has not kept up with this increase, resulting in a widening gap.

technology

It is a manner of accomplishing task, especially using technical processes, methods, or knowledge.

processor technologies, IC technologies, design technologies

What are the 3 technologies central to embedded system design?

Processor technology

It involves the architecture of the computation engine used to implement a system’s desired functionality.

General-Purpose processor

A device that is suitable for a variety of applications, to maximize the number of devices sold.

program memory

It is a feature of general-purpose processors in which the designer does not know what program will run on the processor, so cannot build the program into the digital circuit.

general datapath

Another feature of general-purpose processor in which the datapath must be general enough to handle a variety of computations, so typically has a larger register file and one or more general-purpose arithmetic-logic units (ALUs).

Program Counter

PC meaning?

Instruction Register

IR meaning?

Gordon Moore

The co-founder of Intel who predicted in 1965 that the transistor density of semiconductor chips would double roughly every 18-24 months.

1965

When did Gordon Moore predict that the transistor density of semiconductor chips would double roughly every 18-24 months?

Moore’s Law

Gordon Moore’s very accurate prediction is known as what?

TRUE

(TRUE or FALSE) General-purposed processors are software-based.

single-purpose processor

It is a digital circuit designed to execute exactly one program.

TRUE

(TRUE or FALSE) In single-purpose processors, all of the components other than the microcontroller are single-purpose processors.

single-purpose processor

Many people referred to this as the “hardware” portion of implementation.

Application-Specific Instruction-set Processor (ASIP)

This can serve as a compromise between the general-purpose and single-purpose processors.

ASIP (application-specific instruction-set processor)

This is designed for a particular class of applications with common characteristics, such as digital-signal processing, telecommunications, embedded control, etc.

assembly language

Due to the lack of ratargetable compilers that can exploit the unique features of a particular ASIP, designers using ASIPs often write of the software in this language.

Digital-signal processors (DSPs)

These are a common class of ASIP.

DSP (digital-signal processor)

It is a processor designed to perform common operations on digital signals, which are the digital encodings of analog signals like video and audio.

TRUE

(TRUE or FALSE) Every processor must eventually be implemented on an IC.

IC technology

This involves the manner in which we map a digital (gate-level) implementation onto an IC.

IC (Integrated Circuit)

It is often called a “chip,” is a semiconductor device consisting of a set of connected transistors and other devices.

CMOS (Complementary Metal Oxide Semiconductor)

What is the most popular IC?

transistors

The bottom layers of IC consist of what material?

logic gates

What do the middle layers of IC form?

connect the logic gates with wires

What do the top layers of IC do?

photo-sensitive chemicals are deposited on the chip surface and then shining light through masks to change regions of the chemicals.

How are the layers of IC created?

a layout

What is a set of masks called?

feature size

What is the term for the narrowest line that we can create on a chip?

below one micrometer (sub-micron)

What is the value for feature mask?

Full-custom IC design

It has very high NRE cost and long turnaround times (typically months) before the IC becomes available, but can yield excellent performance with small size and power. It is usually used only in high-volume or extremely performance-critical operations.

VLSI (Very Large Scale Integration) design

Full-custom IC design is often referred to as what?

Application-Specific IC

ASIC

Semi-custom ASIC (gate array and standard cell)

The remaining task is to arrange portions to achieve particular implementation.

PLD (Programmable Logic Device) technology

In this IC technology, all layers already exist, so we can purchase the actual IC.

programmers

What are the small devices in PLD called?

simple and complex

What are the two types of PLD?

PLA (Programmable Logic Array)

It is a simple PLD that consists of a programmable array of AND gates and a programmable array of OR gates.

PAL (Programmable Array Logic)

It is a type of simple PLD that uses just one programmable array to reduce the number of expensive programmable components.

FPGA (Field Programmable Gate Array)

It is a complex PLD that offers more general connectivity among blocks of logic, rather than just arrays of logic as with PLAs and PALs, and are thus able to implement far more complex designs.

compilation/synthesis

It lets a designer specify desired functionality in an abstract manner, and automatically generates lower-level implementation details.

logic synthesis

It is a tool that converts Boolean expressions into a connection of logic gates (called a netlist)

netlist

A connection of logic gates

register-transfer (RT) synthesistool

It converts finite-state machines and register-transfers into a datapath of RT components and a controller of Boolean equations.

behavioral synthesis tool

It is a tool that converts a sequential program into finite-state machines and register transfers.

software compiler

It converts a sequential program to assembly code, which is essentially register-transfer code.

system synthesis tool

It converts an abstract sytem specification into a set of sequential programs on general and single-purpose processors.

Hardware/software codesign

It is the field that emphasizes this unified view, and develops synthesis tools and simulators that enable the co-development of systems using both hardware and software.