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IT 2354 EMBEDDED SYSTEMS2 MARKS & 16 MARKS QUESTION BAN

DEPARTMENT OF IT/SVSCE 1

UNIT I

EMBEDDED COMPUTING

Challenges of Embedded Systems Embedded system design process. Embedded processors

8051 Microcontroller, ARM processor Architecture, Instruction sets and programming.

2 MARKS QUESTIONS

1. What is embedded system?

An embedded system is a special-purpose computer system designed to perform a

dedicated function

An embedded system can be described as one containing a processor, associatedperipherals and software used for a specific purpose

An embedded system performs a single well defined task. It is a combination of

hardware and software.

2. What is embedded computer System?

Any device that includes a programmable computer but is not itself intended to be a

general-purpose computer is called embedded computer system

3. What are the requirements of embedded system?

Requirements may be functional or non-functional. Requirements include

i. Performance

ii. Cost effectiveness

iii. Physical size and weight

iv. Low Power consumption

v. Efficient processing powervi. Efficient memory usage

vii. Appropriate execution time

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4. What is microprocessor?

A microprocessor is a single-chip CPU. Microprocessors come in many different levels

of sophistication; they are usually classified by their word size. Microprocessors execute

programs very efficiently. e.g.) the first microprocessor, the Intel 4004, was designed for anembedded application, namely, a calculator.

5. Give the characteristics of embedded system.

Single functioned

Tightly constrained

Reactive and real time

Complex algorithms

User interface

6. What are the design metrics of embedded system?

Performance

Power

Size

NRE (Non-Recurring Engineering cost).

7. What are the challenges of embedded system?

Hardware needed

Meeting deadlines

Minimizing power consumption

Design for upgradability

8. Give the steps in embedded system design.

A. Requirements

B. Specification

C. Architecture Design

D. Designing Hardware and Software Components

E. System Integration

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9. Give the types of embedded system costs.

Cost typically has two major components:

Manufacturing cost includes the cost of components and assembly;

Non Recurring engineering (NRE) costs include the personnel and other costs of

designing the system.

10. Brief NRE cost.

NRE refers to the Non Recurring Engineering cost. The one time monitory cost of designing

the system. Once the system is designed, any number of units can be manufactured without incurring any

additional cost. Hence the name.

11 What is the specification of embedded system?

It serves as the contract between the customer and the architects. The specification should

be understandable enough so that someone can verify that it meets system requirements and

overall expectations of the customer.

12. What is system integration?

In system integration, the components built are put together and see how the system

works. If we debug only a few modules at a time, we are more likely to uncover the simple bugs

and able to easily recognize them. Only by fixing the simple bugs early will we be able to

uncover the more complex or obscure bugs.

13. What is meant by embedded processor? Give its categories.

When a microcontroller/microprocessor is specifically designed with the capabilities such

as

Fast context switching

Atomic ALU operations

it is called embedded processor.

Embedded processors can be broken into two broad categories: ordinary microprocessors

(P) and microcontrollers (C), which have many more peripherals on chip, reducing cost and

size.

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14. What is a Microcontroller?

A microcontroller is a device possessing some or all of the specialized instructions and

peripheral devices, communication devices, etc. e.g.) 8051 Microcontroller.

15. What is 8051 microcontroller?

8051 is an excellent device for building many embedded systems. One important factor is

that the 8051 requires a minimum number of external components in order to operate.

It is a well-tested design; introduced in its original form by Intel in 1980.

16. Give the features of 8051 microcontroller.

RAM 128 Bytes (Data memory)

ROM 4Kbytes.

Serial Port Using UART makes it simpler to interface for serial communication.

Two 16 bit Timer/ Counter, Input/output Pins 4 Ports of 8 bits each on a single chip.

6 Interrupt Sources

8 bit ALU (Arithmetic Logic Unit)

Harvard Memory Architecture It has 16 bit Address bus (each of RAM and ROM) and

8 bit Data Bus.

8051 can execute 1 million one-cycle instructions per second with a clock frequency of

12MHz.

17. Draw the block diagram of 8051 microcontroller

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18. Give the external interfaces of Standard 8051?

Small 8051:Low-cost members of the 8051 family with reduced number of port pins, and

no support for off-chip memory. Typical application: Low-cost consumer goods.

Standard 8051: The Small 8051s and the Extended 8051s are derived

Extended 8051: Members of the 8051 family with extended range of no-chip facilities

(e.g. CAN controllers, ADC, DAC,etc), Typical applications: Industrial and automotive

systems.

19. List the types of Memory.

Dynamic RAM (DRAM)

Static RAM (SRAM)

Mask Read-Only Memory (ROM)

Programmable Read-Only Memory (PROM)

UV Erasable Programmable Read-Only Memory (UV EPROM)

EEPROM and Flash ROM

20. Distinguish static RAM and Dynamic Ram.

Dynamic RAM Static RAM

Dynamic RAM is a read-write memory

technology that uses a small capacitorto store information.

Static RAM is a read-write memory

technology that uses a form ofelectronic flip-flop to store the

information

It must be frequently refreshed tomaintain the required information

No refreshing is required

Less complex and least cost More complex and costs can be severaltimes that of the corresponding size of

DRAM

Access time is large compared to

SRAM

Access times may be one-third those of

DRAM

21. What is Mask Read-Only Memory (ROM)?

Mask ROM is from the software developers perspective read only; A mask

is provided by the company for which the chips are being produced. Such devices are

therefore sometimes referred to as factory programmed.

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22. What is Programmable Read-Only Memory (PROM)

PROM is a form of Write-Once, Read-Many (WORM) or One-Time

Programmable (OTP) memory. Basically, we use a PROM programmer to blow tiny

fuses in the device.

23. What is UV Erasable Programmable Read-Only Memory (UV EPROM) :

UV EPROMs are programmed electrically. Unlike PROMs, they also have a quartz

window which allows the memory to be erased by exposing the internals of the device to

UV light.

24. Define data memory and code memory.

DATA memory: DATA memory is used to store variables and the program stack while the

program is running. The DATA area will be implemented using some form of RAM

CODE memory: CODE area is used to store the program code, usually in some form of

ROM. The CODE area may also contain read-only variables (constants), such as filter co-

efficient or data for speech playback.

25. State the usage of timers.

It used to measure intervals of time.

Use it to generate precise hardware delays.

Use it to generate time out facilities: this is a key requirement in systems with real-

time constraints.

Used to drive an operating system

26. What is an interrupt? State the interrupt sources of 8051.

An interrupt is a hardware mechanism used to notify a processor that an event has taken place:

such events may be internal events (such as the overflow of a timer) or external events (suchas the arrival of a character through a serial interface).The original 8051 (8052) architecture

supported seven interrupt sources:

Two or three timer/counter interrupts

Two UART-related

Two external interrupts & The power-on reset (POR) interrupt

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27. What are the 3 power saving modes?

Normal mode.

Idle Mode.

Power-Down Mode.

28. What are the two typical addressing modes available for ARM processor?

The ARM processor can be configured at power-up to address the bytes in a word in either

little-endian mode (with the lowest-order byte residing in the low-order bits of the word)

big-endian mode (the lowest-order byte stored in the highest bits of the word)

29.What is CPSR?

The other important basic register in the programming model is the current program

status register (CPSR). This register is set automatically during every arithmetic, logical, or

shifting operation.

30. State the usage top four bits of CPSR.

The negative (N) bit is set when the result is negative in twos-complement arithmetic.

The zero (Z) bit is set when every bit of the result is zero.

The carry (C) bit is set when there is a carry out of the operation.

The overflow (V) bit is set when an arithmetic operation results in an overflow.

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16-MARKS QUESTIONS

1. Explain in detail about embedded systems

2. Write short notes on embedded processors

3. Explain in detail 8051 microcontroller.

4. Draw the Pin configuration and explain 8051 Microcontroller.

5. Explain in detail the steps of design process

6. Explain in detail the hardware and software block diagrams.

7. Specify the challenges in embedded system design

8. Explain the memory issues of 8051 microcontroller.

9. Explain the interrupts in 8051 microcontroller

10. Write the flow of control in ARM.

11. Specify the data operations with example in ARM

12. Explain the Reset requirements and clock frequency performance in 8051.

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UNIT II

MEMORY AND I/O MANAGEMENT

Programming Input and Output Memory system mechanisms Memory and I/O devices and

interfacing Interrupts handling.

2 MARKS QUESTIONS

1. Distinguish data register and status register.

Data registers hold values that are treated as data by the device, such as the data read or

written by a disk.

Status registers provide information about the devices operation, such as whether the

current transaction has completed.

2. What is UART?

UART refers Universal Asynchronous Receiver/Transmitter.e.g) 8251 UART is a device

which is employed for the purpose of serial communications

It gets serial data and stores it as parallel data and viceversa.

3. What is baud rate?

At an uniform rate, normally the data bits are transmitted as high and low voltages. This

is said to be baud rate.

4. Give the parameters of serial port.

Baud rate

Bits count/character

Parity bit Odd/even parity

Stop bit length

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5. Define memory mapped I/O

Memory-mapped I/O provides addresses for the registers in each I/O device. Programs

use the CPUs normal read and write instructions to communicate with the devices

6. Define peek and poke

These are the two functions used to read and write in memory locations.

Peek( ):

The peek function can be written in C as:

int peek(char *location)

{

return *location; /* de-reference location pointer */

}

The argument to peek is a pointer that is de-referenced by the C * operator to

read the location.

Poke ( ):The poke function can be implemented as:

void poke(char *location, char newval)

{

(*location) = newval; /* write to location */

}

To write to the status register, we can use the following code:

poke(DEV1,8); /* write 8 to device register */

8. What is busy wait I/O?

The most basic way to use devices in a program is busy-wait I/O. If the CPU is

performing multiple operations on a single device, such as writing several characters to an

output device, then it must wait for one operation to complete before starting the next one.

9. What is polling?

It is a process of knowing the situation by reading the status register whether the I/O

devices completes its operation or not.

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10. What is NMI?

The highest-priority interrupt is normally called the Non Makeable Interrupt (NMI).The NMI

cannot be turned off and is usually reserved for interrupts caused by power failures.

11. Distuinguish cache hit and Cache miss.The cache controller sends a memory request to the cache and main memory.

If the requested location is in the cache, the cache controller forwards the locations contents to

the CPU and aborts the main memory request; this condition is known as a cache hit.

If the location is not in the cache, the controller waits for the value from main memory

and forwards it to the CPU; this situation is known as a cache miss.

11. State the types of cache miss.

We can classify cache misses into several types depending on the situation that generated

them:

A compulsory miss (also known as a cold miss) occurs the first time a location is used,

A capacity miss is caused by a too-large working set, and

A conflict miss happens when two locations map to the same location in the cache.

12. Define average memory access time.

We can compute the average memory access time as

tav_ htcache +(1 _ h)tmain

where tcache is the access time of the cache and tmain is the main memory access time. The

memory access times are basic parameters available from the memory manufacturer.

12. Distinguish write through policy and write back policy

Write-through policy: Every write changes both the cache and the corresponding main

memory location (usually through a write buffer). This scheme ensures that the cache and

main memory are consistent, but may generate some additional main memory traffic.

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Write back policy: We can reduce the number of times we write to main memory by

using a write-back policy: If we write only when we remove a location from the cache,

we eliminate the writes when a location is written several times before it is removed from

the cache.

13. What is page fault?

When the CPU requests an address that is not in main memory, the MMU generates an exception

called apage fault.

14. What are the two styles of address translation

There are two styles of address translation: segmented andpaged

15. What are SIMMs and DIMMS?

Memory for PCs is generally purchased as single in-line memory modules (SIMMs) or double in-

line memory modules (DIMMs). A SIMM or DIMM is a small circuit board that fits into a standard

memory socket. A DIMM has two sets of leads compared to the SIMMs one. Memory chips are soldered

to the circuit board to supply the desired memory.

16. What is a keyboard .Give the categories of keyboard.

A keyboard is basically an array of switches, but it may include some internal logic to help

simplify the interface to the microprocessor.

A raw keyboard can be assembled from several switches. Each switch in a raw keyboard

has its own pair of terminals, making raw keyboards impractical when a large number of

keys is required.

An encoded keyboard uses some code to represent which switch is currently being

depressed

17. What is LCD.List its panel types.

A LED single-digit display typically consists of seven segments; each segment may be either an LED

or a liquid crystal display (LCD) element. This display relies on the digits being visible for some time

after the drive to the digit is removed, which is true for both LEDs and LCDs.The LCD panel is of 2

types.They are

1. Passive matrix

2. Active matrix

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18. What is interfacing?

The process of implementing communication with buses is said to be interfacing. It is of 2 types.

1. Memory Interfacing

2. Device Interfacing

19. What is Translation Look Aside buffer (TLB)?

The efficiency of paged address translation may be increased by caching page translation

information. A cache for address translation is known as a translation look aside buffer (TLB).

20. What is glueless interface?

Some I/O devices are designed to interface directly to a particular bus, forming glue less

interfaces.

21. What is glue logic?

Glue logic is required when a device is connected to a bus for which it is not designed.

22. What is RS232?

RS-232 is a byte-oriented protocol. That is, it is intended to be used to send single 8-bit blocks of

data. To transmit a byte of data over an RS-232 link, we generally encode the information as

follows:o We send a Start bit.

o We send the data (8 bits).

o We send a Stop bit (or bits)

23. What is MMU?

Modern microprocessor units (MMUs) perform address translations that provide a

larger virtual memory space in a small physical memory.

24. Differentiate active matrix and passive matrix?

Early LCD panels were called passive matrix because they relied on a two-dimensional

grid of wires to address the pixels. Modern LCD panels use an active matrix system that puts a

transistor at each pixel to control access to the LCD. Active matrix displays provide higher

contrast and a higher-quality display.

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25.What are A/D and D/A convertors?

Analog/digital (A/D) and digital/analog (D/A) converters (typically known as ADCs and DACs,

respectively) are often used to interface non digital devices to embedded systems.

16 MARKS QUESTIONS

1. Explain in detail about programming I/O.

2. Explain Busy wait I/O.

3. Explain Interrupts

4. 4.Explain I/O devices with examples.

5. Write notes on

a. a.LEDs

b. b.Touch screens

c. c.Displays

6. Explain memory devices in detail.

7. Explain ROM in detail

8. Explain Memory Interfacing and I/O interfacing

9. Write notes on parallel and serial interfacing architectures.

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UNIT III

PROCESSES AND OPERATING SYSTEMS

Multiple tasks and processes Context switching Scheduling policies Interprocess

communication mechanisms Performance issues.

2 MARKS QUESTIONS

1. Define process.

A process is a single execution of a program. If we run the same program two different

times, we have created two different processes. Each process has its own state that includes not

only its registers but all of its memory.

2. What is a task?

Tasks are part of the systems functionality, but that application-level organization of

functionality is often reflected in the structure of the program as well.

3. What is meant by a thread?

Processes that share the same address space are often called threads

4. What is multirate system?

When multiple rates of computation has followed, it is difficult to write codes for

fulfilling timing needs E.g) printers, cellphones.

5.Define directed acyclic graph?

It is a cycle which is hard to interrupt in a periodically execute system.

6.What is a task graph?

A collection of process with data dependencies is said to be a task graph.

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15. Define priority scheduling?

A simple scheduler maintains a priority queue of process that is in the runnable state.

16. What is rate monotonic scheduling?

It is an approach that is used to assign task priority for a preemptive system.

17. What is a critical instant?

The critical instant for a process is defined as the instant during execution at which the task has

the largest response time

18.Define earliest deadline first scheduling

It is a dynamic priority schemeit changes process priorities during execution based on

initiation times. As a result, it can achieve higher CPU utilizations

18. What is Inter process Communication mechanisms?

Processes often need to communicate with each other.Interprocess communication mechanisms

are provided by the operating system as part of the process abstraction

19. What are the two types of communication?

1. Blocking communication

2. Non blocking communication

20. What are the different styles of Interprocess communication?

1. Shared memory

2. Message passing

21. What are the examples of multi rate systems?

Automobile engines

Printers

Cell phones

22. What are the timing requirements on processes?

Release time

Deadline

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23.What is an aperiodic process?

This is started by an event like

External data arriving

Data computed by another process.

16 MARKS QUESTIONS

1. Explain tasks and processes in detail.

2. Explain in detail cyclostatic scheduling and Round Robin scheduling

3. Write short notes on priority scheduling

4. Give notes on static and dynamic priorities

5. Explain rate monotonic scheduling

6. Explain shared memory and message passing

7. Explain in detail about performance issues.

8. Give an example for test and set operation and explain.

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UNIT IV

EMBEDDED SOFTWARE

Programming embedded systems in assembly and C Meeting real time constraints Multi-state

systems and function sequences. Embedded software development tools Emulators and

debuggers.

1. Define assembly language.

2 MARKS QUESTIONS

In this language each statement denotes one machine instruction and the programmers

have to deal with the low level details such as register allocation and procedure calling

sequences. It is a combination of mnemonics codes

2. State the advantages of assembly languages.

It gives a precise control of processor internal directives

Machine codes are compact

Small memory is enough

It is not compiler specific or library function specific

3. State the advantage of high level language.

Modular programming approach is used.

Type checking makes programming easy

Control structures make the path of the program simple

4. State C-programming elements

a. Header

b. Source files

c. Preprocessor directives

5. What is TCON_SFR?

It is special function register used in timer.

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6. Give the characteristics of multi state systems

a. Series of System states are employed

b. One or more functions are used in every state

c. Transition between states can be illustrated by some rules.

7. Define multi-state systems.

Here the transition between states will depend only on the passage of time.

8. Define Multistate(input/Timed system)?

Here the transition between states will depend both on passage of time and system inputs.

9. What are the types of debugging?

1.Task level debugging

2.symbolic debugging

10. State some embedded software development tools.

1. Cross compilers

2. Cross assemblers.

3. Tool chains

4. Linkers/Locators

5. Locator maps

11.what are the characteristics of multi state system?

The common characteristics of such systems are that:

1. They involve a series of system states.

2. In each state, one or more functions may be called.3. There will be rules defining the transitions between states.

4. As the system moves between states, one or more functions may be called.

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12. What are the characteristics of Time driven in-out driven multistate architecture?

Each state may be associated with one or more function calls.

Transitions between states may be controlled by the passage of time, by system

Inputs or by a combination of time and inputs.

Transitions between states may also involve function calls

13. What is a cross-compiler?

A cross-compiler is a compiler that runs on one type of machine but generates code for

another

14.What is test bench?

The testbench generates inputs to simulate the actions of the input devices; it may also

take the output values and compare them against expected values, providing valuable early

debugging help.

15. What is a breakpoint?

Very important debugging tool is the breakpoint. The simplest form of a breakpoint is for

the user to specify an address at which the programs execution is to break.

16. What is ICE?

The microprocessor in-circuit emulator (ICE) is a specialized hardware tool that can

help debug software in a working embedded system. In-circuit emulator has a special version of

the microprocessor that allows its internal registers to be read out when it is stopped.

17. What is logic analyzer?

Logic analyzer is an array of inexpensive oscilloscopesthe analyzer can sample many

different signals simultaneously (tens to hundreds) but can display only 0, 1, or changing valuesfor each. All these logic analysis channels can be connected to the system to record the activity

on many signals simultaneously

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18. What are the two modes of logic analyzer?

A typical logic analyzer can acquire data in either of two modes that are typically called

state and timing modes

19.What are debugging challenges?

Logical errors in software can be hard to track down, but errors in real-time code can

create problems that are even harder to diagnose. Real-time programs are required to finish their

work within a certain amount of time; if they run too long, they can create very unexpected

behavior

20. Differentiate a host and a target?

It is common to do at least part of the software development on a PC or workstation

known as a host. The hardware on which the code will finally run is known as the target. The

host and target are frequently connected by a USB link, but a higher-speed link such as Ethernet

can also be used.

21. What is task level debugging?

It works at the OS level.

22. Why emulation?

It is needed to resolve problems within a design quickly.

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16 MARKS QUESTIONS

1. Explain in detail about programming in C.

2. Compare assembly language and C.

3. Explain multistate system n detail

4. Explain Real time constraints with example

5. Explain Multi state system in detail

6. Implement multistate system with example

7. Explain emulators and debuggers

8. Explain embedded software development tools.

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UNIT V

EMBEDDED SYSTEM DEVELOPMENT

Design issues and techniques Case studies Complete design of example embedded systems.

2 MARKS QUESTIONS

1. What are the specification of the product?

Fuctionality

Performance

Manufacturing cost

2. What are the three important objectives of a design process?

Time to market

Design cost

Quality

3. On which factors does the quality of the product rely?

Correctness

Reliability

Usability

4. What are the internal and external forces that modify a process?

Changing customers

Changing requirements

Changing products

Changing components

5. What are design tools?

Compilers

CAD systems

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6. What are the steps in software development process?

Requirement analysis

Architecture design

Coding

Testing

Maintenance

7. What is the advantage of spiral model?

It is more realistic then waterfall model

Design is fulfilled due to many iterations

8. What is concurrent engineering?

It allows broader approach among the people in design of complex embedded systems.

It optimizes the total flow

Its main goal is to reduce design time

8. What are the elements of concurrent engineering?

Cross functional teams

Concurrent product realization process activities

Incremental information sharing

Integrated project management

Early and continual supplier environment

Customer focus

9. What are the types of requirements?

Functional Non-functional

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10. What are the ways to determine requirements?

Conducting surveys

Organizing focus groups

Asking customers to test a prototype.

11. What is state chart model?

It is a well known technique for state based specification.It uses an event driven model .It

permits states to be combiled together to express common functionality.

12. What are the two types of grouping?

OR group

AND group

13.Define CRC method

CRC refers classes, Responsibilities and collaborators

It is a technique used for identifying classes and responsibilities

It helps to identify classes

14.What are the 3 steps in CRC process?

Identify class responsibilities

Assign responsibilities

Identify collaborators.

15.What is CMM?

It stands for capability Maturity model that includes software and system engineering

capability assessment

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16.What is six point scale in CMM?

Not performed

Performed

Managed

Defined

Quantitatively managed

Optimizing

17. What is control oriented specification language?

To specify control in UML state machines are generally used.E.g SDL.It is a language

used to specify control in UML.

18. Define specification.

It represents the more detailed, precise and more constant , consistent descriptions of a

system which can be used to create the architecture

19. What is the use of successive refinement development model?

It is used to understand the system on which designer is working by a series of design

cycles

20. What are non-functional requirements?

It refers to attribute collection

e.g cost, physical size, power consumed, reliability etc

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16 MARKS QUESTIONS

1. Write short notes on design process and design methodologies.

2. Explain design flow.

3. Explain waterfall model and spiral model

4. With neat diagram explain successive refinement development model.

5. Write short notes on Concurrent engineering and specification

6. Explain CRC.

7. Explain ISO 9000 certification in detail

8. Give techniques for quality assurance and explain

9. Draw and explain state chart diagram

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