1. DEPT OF ELECTRICAL AND ELECTRONICS ENGG
JCT COLLEGE OF ENGINEERING AND
TECHNOLOGY
Coimbatore – 641 105
DEPARTMENT OF ELECTRICAL AND ELECTRONICS
ENGINEERING
TWO MARK QUESTION BANK
EE 6602 – EMBEDDED SYSTEMS
Prepared by
MANIKANDAN S
Asst. Prof / EEE
JCT College of Engg &
Tech
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UNIT – I
INTRODUCTION TO EMBEDDED SYSTEMS
1. Define a System. Now define an Embedded System.
A way of working, organizing or doing some tasks by following fixed
plan, program, and set of rules (Eg:Timer display system).
An Embedded system is a system that has embedded software and Computer
– Hardware, which makes it a system dedicated for an application(s) or specific part
of an application or product or a part of a larger system.
2. What are the Challenges faced in designing an embedded system.
Amount and Type of Hardware needed
Optimizing Power Dissipation and Consumption
Clock Rate Reduction
Voltage Reduction
Wait, Stop and cache disable Instructions
Process Deadlines
Flexibility and Upgrade ability
Reliability
3. Define ROM image.
The Process of Converting an assembly language program in to the machine
codes and finally obtaining ROM image.
It is a program reallocates the linked files of the program application
and the RTOS codes at the actual addresses of the ROM memory. It
creates a file in a standard format. File is called ROM image.
4. What is the role of RAM in an embedded system?
This is a random access read and writes memory that the processor uses to
store programs and data that are volatile and which disappear on power down or
when switched off.
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5. Explain the need of Watchdog timer and reset after the watched time.
A timing device in a system that resets or executes a Watchdog timer service
routine (WDT routine) after fetching the interrupt vector address at the system after
a predefined time out in case a watched event does not happen. When the watched
event occurs, it is restarted so that it does not timeout and does not execute WDT
routine.
6. What is Target System?
A system which has hardware similar to that of the final product and on which
the embedded software has to run.
7. How does an ICE differ from Target?
The Target uses the circuit consisting of the microcontroller or processor itself.
The emulator emulates the Target system with extended memory and with codes –
downloading ability during the edit – test – debug cycles. ICE emulates the processor
or microcontroller. It uses another circuit with a card that connects to the target
processor through a socket.
8. Define RTC (Real Time Clock).
Real time clock is a clock which once the system stats does not stop and cant
be reset and its count value cant be reloaded.
9. What is mean by Software Timer?
Software (a service routine) that executes and increases or decreases a count
variable on an interrupt from a real – time clock interrupt. A software timer also
generates interrupt on overflow of count – value or an finishing value of the count –
variable or generating a message for a tasks. The interrupts can generate by using
software interrupt instruction such as SWI.
10. Define System Clock.
A clock scaled to the processor clock and which always increments with out
stopping or resetting and generates interrupts at preset time intervals.
11. What are the main components of an embedded system?
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Microprocessor, memory (primary-RAM, ROM and secondary- hard disk),
input units (keyboard, mouse, scanner), output units (video monitor, printer),
networking units (Ethernet card, drivers), I/O units (modem).
12. What are the various classifications of embedded systems?
General purpose processor - microprocessor, microcontroller, embedded
processor, DSP, media processor.
ASSP-application specific system processor Multiprocessor system using
General purpose processor (GPP) and Application specific instruction
processor[ASIP].
GPP core or ASIP core or VLSI circuit.
13. Give some examples for Small and Medium scale embedded systems.
Small Scale:
Automatic chocolate vending machine, washing system, multitasking
Toys, keyboard controller, serial port controllers, CD drive and hard disk drive.
Medium Scale:
Computer networking router, internet appliances, entertainment
system, banking system, signal tracking system, communication system,
TCP/IP, DNA sequence and pattern storage memory card and DNA pattern
recognizer.
14. Define DMA and DMA Controller.
Direct Memory Access is a bus operation that allows reads and writes not
controlled by the CPU. A DMA transfer is controlled by a DMA controller, which
requests control of the bus from the CPU
A device that facilitates DMA transfer has a processing element is called as
DMA controller or DMAC.
15. Give some examples for small scale embedded systems.
Automatic chocolate vending machine, Washing system, Multitasking Toys,
Keyboard Controller, Serial Port Controllers, CD drive and hard disk drive.
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UNIT – II
EMBEDDED NETWORKING
1. Differentiate synchronous communication and iso - synchronous Communication.
Synchronous communication
When a byte or a frame of the data is received or transmitted at constant
time intervals with uniform phase difference, the communication is called
synchronous
communication.
Iso-synchronous communication
Iso-synchronous communication is a special case when the maximum time
interval can be varied.
2. Define device driver.
Interrupt service routine software, which runs after the programming of
the control register of a peripheral device (or virtual device) and to let the device get
the inputs or outputs. It executes on an interrupt to or from the device.
3. What is meant by port?
A port is a device,
To receive bytes from external peripherals for reading them later using
instructions executed on the processor.
To send the bytes to External peripheral or device or processor using
instructions executed on the processor.
4. What is I2C?
Ait is a standard bus that follows a communication protocol and is used
between multiple ICs. It permits a system to get data and send data to multiple
compatible ICs connected on bus.
5. What is a CAN bus? Where is it used?
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CAN bus is a control area network CAN is a serial bus for interconnecting a
central control network. It is mostly used in automobiles. It has fields for bus
arbitration bits, control bit for address and data length, data bits, CRC check bits,
acknowledgement bits and ending bits.
6. List out the different standard versions for CAN and I2C bus with its different
speed level.
CAN Bus
Low Speed CAN – 125 Kbps: 11 Bit Identifier
Standard CAN 2.0A – 1Mbps: 11 Bit Identifier
External CAN 2.0B - 1Mbps: 29 Bit Identifier
I2C Bus
Slow – Under 100 Kbps
Fast – 400Kbps
High – 3.4 Mbps
7. What are the two characteristics of synchronous communication?
Bytes maintain a constant phase difference. It means they are synchronous.
They are no permission for sending either the bytes or the frames at random
time intervals, this mode provides for no handshaking during communication.
The transmitter is the master and receiver is slave.
A clock is ticking at a certain rate ha to be always there for transmitting
serially the bits for all the bytes. The clock is not implicit to the synchronous
data receiver.
8. What are the two characteristics of Asynchronous communication?
Bytes need not to be maintaining a constant phase difference and are
asynchronous. Bytes or frames can be sent at variable time intervals. This
mode facilitates in between handshaking between serial transmitter and serial
receiver port.
It is always implicit to the asynchronous data receiver. The transmitter does
not transmit along with the serial stream of bit any clock rate information in
asynchronous frequency and constant phase difference with transmitter clock.
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9. List out the Serial Communication Systems.
Simplex Connection
Half – Duplex Connection
Full – Duplex Connection
10. Define Bus.
A Bus is a collection of wires which carry electrical signals. The electrical
signals may be defined in terms of voltage level or current values.
11. What are the two actions take place in an SPI clock cycle.
The Master sends a bit on the MOSI line which the Slave reads from the same
line.
The Slave sends a bit on the MISO line and the Master reads it from that same
line.
12. Define half-duplex and Full - Duplex communication.
Half Duplex:
Transmission occurs in both the direction, but not simultaneously.
Full Duplex:
Transmission occurs in both the direction, simultaneously.
13. What are the three ways of communication for a device?
Iso - synchronous communication.
Synchronous communication.
Asynchronous communication.
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UNIT – III
EMBEDDED FIRMWARE DEVELOPMENT ENVIRONMENT
1. Define EDLC.
EDLC is Embedded Product Development Life Cycle. It is an Analysis – Design
– Implementation based problem solving approach for embedded systems
development.
2. What are the purposes of using EDLC?
EDLC is essential for understanding the scope and complexity of the work
involved in embedded systems development.
It can be used in any developing any embedded product.
EDLC defines the interaction and activities among various groups of a product
development phase.
Example:-project management, system design
3. What are the three phases of Product Development?
Analysis involves understanding what product needs to be developed.
Design involves what approach to be used to build the product.
Implementation is developing the product by realizing the design.
4. What are the different phases of EDLC?
Need
Conceptualization
Analysis
Design
Development and Testing
Deployment
Support
Upgrades
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Retirement / Disposal
5. What are the different types of approaches can be used to model an embedded
system.
Waterfall or Linear Model.
Iterative/ Incremental or Fountain Model.
Prototyping Model.
Spiral Model.
6. Define System testing.
Testing the functional aspects or product requirements of the product after
integration. System testing refers to a set of different tests and few among them are,
usability testing, loading testing, security testing, Scalability testing, Sanity testing,
Smoke testing, Performance testing and Endurance testing.
7. Define Integration Testing.
Integrating each modules and testing the integrated unit for required
functionality is called as Integration testing.
8. What are the Computational models commonly used in Embedded System Design.
Data Flow Graph (DFG) model
State Machine model
Concurrent Process model
Sequential Program model
Object Oriented model
9. Define Data Flow Graph (DFG) model.
The DFG model is a driven model in which the program execution is
determined by data. It is also called as Diagram Model.
10. What is meant by State Machine Model?
The State Machine Model describes the system behaviour with States, Events,
Actions and Transitions. The state machine model is used for modelling reactive or
event driven embedded systems whose processing behaviour are dependent on state
transitions.
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11. Define FSM Model.
A Finite State Machine model is one in which the number of states are finite. In
other words the system is described using a finite number of possible states.
12. Define object oriented model.
The object oriented model is an object based model for modelling system
requirements. It disseminates a complex software requirement into simple well
defined pieces called objects. Object – oriented model brings re – usability,
maintainability and productivity in system design.
13. What is meant by Sequential Program Model?
In the sequential program model, the functions or processing requirements are
executed in sequence. It is same as the conventional procedural programming.
14. What is the use of control DFG Model?
The control DFG (CDFG) model is used for modelling applications involving
conditional program execution. CDFG model contains both data operations and
control operations.
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UNIT – IV
RTOS BASED EMBEDDED SYSTEM DESIGN
1. Define task and Task state.
A task is a set of computations or actions that processes on a CPU under the
control of a scheduling kernel. It also has a process control structure called a task
control block that saves at the memory. It has a unique ID. It has states in the
system as follows: idle, ready, running, blocked and finished.
2. What is a thread?
Thread is a concept in Java and UNIX and it is a light weight sub process or
process in an application program. It is controlled by the OS kernel. It has a process
structure, called thread stack, at the memory. It has a unique ID .It have states in
the system as follows: stating, running, blocked and finished.
3. Define Inter process communication.
An output from one task passed to another task through the scheduler and use
of signals, exception, semaphore, queues, mailbox, pipes, sockets, and RPC.
4. What is shared data problem?
If a variable is used in two different processes and another task if interrupts
before the operation on that data is completed then the value of the variable may
differ from the one expected if the earlier operation had been completed .This ids
known as shared data problem.
5. Define Semaphore.
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Semaphore provides a mechanism to let a task wait till another finishes. It is a
way of synchronizing concurrent processing operations. When a semaphore is taken
by a task then that task has access to the necessary resources. When given the
resources unlock. Semaphore can be used as a event flag or as a resource key.
6. Differentiate counting semaphore and binary semaphore.
Binary semaphore
When the value of binary semaphore is one it is assumed that no task has
taken it and that it has been released. When the value is 0 it is assumed that it has
been taken.
Counting semaphore
Counting semaphore is a semaphore which can be taken and given number of
times. Counting semaphores are unsigned integers.
7. What is Priority inversion?
A problem in which a low priority task in advertently does not release the
process for a higher priority task.
8. What is Deadlock situation?
A set of processes or threads is deadlocked when each process or thread is
waiting for a resource to be freed which is controlled by another process.
9. Define Message Queue.
A task sending the multiple FIFO or priority messages into a queue for use by
another task using queue messages as an input.
10. What are the goals of RTOS?
Facilitating easy sharing of resources
Facilitating easy implantation of the application software
Maximizing system performance
Providing management and organization functions for the devices and files and
file like devices.
Portability
Interoperability
Providing common set of interfaces.
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11. What is RTOS?
An RTOS is an OS for response time controlled and event controlled processes.
RTOS is an OS for embedded systems, as these have real time programming issues
to solve.
12. Write short notes on Vxworks?
Vxworks is a popular Real-time multi-tasking operating system for embedded
microprocessors and systems.
Vxworks can run on many target processors.
It is a UNIX like Real time operating system.
More Reliable.
More faster.
13. What is sophisticated multitasking embedded system?
A system that has multitasking needs with multiple features and in which the
tasks have deadlines that must be adhered to.
14. What is MICRO C/OS II?
It stands for micro-controller operating system (UC/OS II).
It is a real time kernel.
The other names of MICROC/OS II are MUCOS and UCOS.
The codes are in ‘C’ and Assembly language.
15. Define Pipe.
Pipe is a section of the shared memory used by processes for communicating.
Pipes follow the client server architecture. Pipes can be either unidirectional or bi
directional information flow.
16. What is meant by Multitasking?
The ability of an OS to hold multiple processes in memory and switch the CPU
from executing one process to another process is known as multitasking.
17. Define Context Switching.
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The act of Switching CPU among the processes or changing the current
execution context is known as context switching.
18. What is meant by Message Passing?
Message Passing is a synchronous or asynchronous information exchange
mechanism used for Inter process communication or Thread communication.
UNIT – V
EMBEDDED SYSTEM APPLICATION DEVELOPMENT
1. Define Spin Phase.
In the second phase of washing, water is pumped out from the
tub and the inner tub uses centrifugal force to writing out more water from the cloths
by spinning at several hundred rotations per minute. This is called Spin Phase.
2. What are all the Software Components used in Smart Card.
Boot – up, initialization and OS programs
Smart Card secure file system
Connection establishment and termination
Communication with host
Cryptography algorithm
Host Authentication
Card authentication
Saving additional parameters
3. What is meant by Application Specific System Processor (ASSP)?
A processing unit for system specific tasks, for example, image processing,
compression and decompression, and that is integrated through the buses with the
main processor in embedded system.
4. Define Adaptive Algorithm.
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An algorithm that adjust and adapts to the parameters and limits the changing
perturbations in a control system.
5. What is the use of Radar?
A system that uses radio waves of below 1m to enable ranging of short distant
objects by measuring time delay between transmitted signal and reflected signal.
6. What is meant by Invalidation Lock.
A lock, which, if placed in the application data files in the card, makes the card
invalid for further use.
7. Define GPS.
A system for determining location, speed, direction and time by a receiver. A
set of 24 or more medium earth orbit satellites beams the signals to enable a GPS
receiver. The receiver is positioned at any place on globe to receive signals for
determining these four parameter.
8. What is meant by Fabrication Key?
A key embedded in ROM at the time of card Fabrication so that the card gets a
unique identity.
9. List the embedded devices in High end Car.
Engine control
Speed control and Brake
Safety systems
Seat and pedal control
Car environment control
Route and Traffic monitors
Automobile status monitoring
System interfaces for commands, voice activation and interfacing
Infotainment systems
10. What are all the design metrics in Automobile application?
Power source and dissipation
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Resolution
Performance
Process Deadlines
User Interface
Extendibility
Engineering Cost
Manufacturing Cost
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