DEPARTMENT OF ELECTRONICS & INSTRUMENTATION

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1 DEPARTMENT OF ELECTRONICS & INSTRUMENTATION Question Bank : CS 2361 EMBEDDED SYSTEM 1. Define Embedded Systems. An embedded system is one that has computer hardware with software embedded on it as one of its most important component. An embedded system is a computing device that does a specific and repetitive job. 2. Write some applications of Embedded Systems. Smart card Missiles & Satellites Computer Networking Au to mo tive s 3. What are the classifications of Embedded system? Small scale Embedded System Medium scale Embedded System Sophisticated Embedded System. 4. Give examples for Small, Medium & sophisticated scale embedded systems. Small Scale Embedded System Automatic chocolate vending machine Stepper motor controller for a robotics system Washing or cooking system Multitasking toys Medium Scale Embedded System Computer Networking Systems Entertainment systems Embedded firewall / Router Signal tracking system Sophisticated Scale Embedded System Embedded system s for wireless LAN & for convergent technologydevices. Security products & high speed network security, gigabit rate encryption rate products Embedded system for real time video & speech 5. List the categories of embedded system. Stand-alone embedded systems. Eg. AC, Oven, CD player, TV. Real-time systems. Eg. Aircraft control, Missile & Satellite control Networked Information appliances. Eg. Weather monitoring system Mobile Devices. Eg. PDAs, Smart phones.

2 6. List the specialties of embedded systems. Re li a bi li ty Pe r f o rma n ce Power Consumption C ost Size Limited User interface Software upgradation capability 7. List the factors to be considered while evaluating the processor for embedded system. Clock Speed Length of Registers Number of Registers Width of Data and Address bus Internal RAM & ROM Interrupt lines No. of programmable I/O lines On-chip peripherals such as Timers, UART, ADC, DAC, etc. 8. What are the hardware components of embedded systems? Input devices, Interfacing/Driver circuits, Pr o ce sso r Ti mer s Interrupt Controller M em or y Serial/Parallel Ports Output Interfacing/Driver circuits Power supply, Reset & Oscillator circuits. 9. Define processor. A processor is a Chip, which implements a process or processes as per thecommand given to it. 10. Define Watch Dog Timer Timing device that resets the system after predefined Timeout.It is activated with in few clock Cycles after the Powerup. 11. Compare CISC and RISC processor. CISC:Complex Instruction Set Computer (CISC) Aim of designing CISC processor is to reduce the softwarecomplexity by increasing the complexity of the processorarchitecture. CISC has large no of instructions. Instructionsrequired to do a job is less and hence, the memoryrequirement in less. No. ofregisters are available in CISCprocessor is very less. Eg. Intel x86 family and Motorola series processors.

3 RISC: Reduced Instruction Set Computer (RISC)RISC has limited no. of instructions and hence, complexoperation is carried out through sequence of more simpleinstructions. Large number of registers is required in RISCprocessor. Another important feature of RISC processor ispipelined instruction execution.embedded systems generally use RISC processor. Eg. ARM, ATMEL, AVR, MIPS, Microchip s PIC family processors,power PC and Sun SPARC processor. 12. What are the processor architectures in embedded systems? Von-Neuman Architecture: This architecture has common memory for both data and program codes. Harvard Architecture: This architecture has separate memory for data and program codes. 13. What is microcontroller? A microcontroller is a unit with a processor. It is a single chip VLSI unitwhich, thought having limited computational capabilities, possesses enhanced input-output capabilities and a number of on-chip functionalunits. 14. What are the functional circuits of a microcontroller? The functional circuits of a microcontroller are, Pr o ce sso r Data & stack in internal RAM Timers & Watchdog timer ROM / PROM / EPROM External Memories Interfaces Interrupt Controller I/O Ports Control & Interfaces / Drivers Serial UART communication port 15. What are the features of DSP? A DSP provides fast, discrete-time, signal processing instructions. It hasvery large instruction word (VLIW) processing capabilities, it processessingle Instruction Multiple Data (SIMD) instructions fast, and it processesdiscrete Cosine Transformations (DCTs) and inverse DCTs (IDTs) fast. 16. What is GPP & ASIP? GPP: A processor from a number of families of processors, microcontroller,embedded processors and DSPs having a general purpose instruction setand readily available compilers to enable programming in a high level language is called a General Purpose Processor (GPP). ASIP: A processor designed for specific application on a VLSI chip is calledan Application Specific Instruction Processor. 17. What is ASSP?

4 Application Specific System Processor is a processing unit for specifictasks, for e.g. Image compression and that is integrated through thebuses with the main processor in an embedded system. 18. What is System-On-Chip? A system on a VLSI chip that has all of needed analog as well as digitalcircuits. For example, mobile phone. 19. What are the various forms of system memories? Internal RAM Internal ROM / PROM /EPROM External RAM Internal & External Caches External ROM / PROM RAM Memory buffers Hybrid memory such as E2PROM, NV-RAM or flash memory 21. List the important types of Displays. Light Emitting Diode (LED) Liquid Crystal Display (LCD) Thin Film Transistor (TFT) Display Organic Light Emitting Diode (OLED) 22. List the important Serial communication protocols. Inter-integrated Circuit (I2C) Serial Peripheral Interface (SPI) Universal Serial Bus (USB) Controller Area Network (CAN) 23. List the important communication interfaces used in embedded systems. Serial interface using RS232 Serial interface using RS422/RS485 Universal Serial Bus (USB) In f r a re d Eth e rn e t Wireless interface using IEEE (WLAN) B lu e to oth ZigBee IEEE Define interrupt handler. It is a unit that handles the processor operations arising out of an interrupt from a source. 25. What is watchdog timer?

5 It is a timer that timeout from which resets the processor in case the program gets struck for an unexpected time. 26. What is reset circuit and power-up reset? The reset circuit activates for a fixed period and then deactivates. It helpsthe processor to start the processing of instructions from a startingaddress.power-up reset vector also provides a starting address which is differentfrom that provided by a reset circuit 27 What are the steps required for converting assembly language intoa ROM image? Assem b le r Lin ker Loa d e r Locator & Device Programmer 28 What is ROM image? The final stage software is also called ROM image, because just as animage is a unique sequence and arrangement of pixels, embeddedsoftware is also a unique placement and arrangement of bytes forinstructions and data. 29. What is the use of code optimizer? Code optimizer is used in the conversion of high level language into a ROMimage for optimizing the code before linking. 30 What is Compiler? Compiler is a software tool that converts a high level program (writtenusing programming languages like C, C++, Java, and so on) into an objectcode. 31 What is Assembler? Assembler is a software tool that converts an assembly program (writtenusing mnemonics of a processor, i.e., instruction set of a specificprocessor) into an object code. 32 What is Timer and counting devices? A Timer gets the inputs from the internal clock of a processor or from system clock and generates a required time delay. Counting device is a unit for getting the count-inputs on the occurrence of events that may be at irregular intervals.

6 33 What are the types of Timer? There are two types of timer. They are, Hardware timer Software timer 34 What are the different states in a timer? The different states in a timer are, Reset State Idle State Present State Overflow State Active or Blocked State Done State 35 Is it necessary to have a hardware timer device in a system? How does it work? Yes, it is necessary to have atleast one hardware timer device in a system. It is used as a system clock. The hardware timer gets the input from a clock out signal from the processor and activates the system clock as per the num ticks preset at the hardware timer 36 Mention the types of data Transfer in USB Bus Controlled Data Transfer, Bulk data Transfer, Interrupt driven data Transfer, Isosynchronous Transfer. 37 what is Real Time Clock? RTC is aclock that causes Occurance of Regular intervals of interrupt on its each Ticks.Timing device once started never resets.it is ysed in System to save Current time & Date. 38 Give the Classification of Serial & Parallel port of IO devices. Synchronous Serial Input Synchronous Serial Ouput Asynchronous Serial UART Input Asynchronous Serial UART Output

7 Parallel Port one bit Input Parallel One bit output Parallel Port Input Parallel Port Output 39 Compare Synchronous & A Synchronous communication In Synchronous Communication a Byte or Frame is Received or Transmitted at Constant Time interval with Uniform Phase difference.data is Sent at Fixed Time interval. Eg Frames sent over LAN. In A Synchronous Communication a Byte or Frame is Received or Transmitted at variabletime interval.eg RS 232 Communication between two UART devices. 40 List the Parallel communicating Buses. ISA,PCI( Peripheral Component Interconnect ), ARM 42 Mention the processor Features in Embedded System It should Operate at high clock Speed Provide High computing performance with Pipelinning & SuperScalar Architecture Provide Fast Context Switching in Multitasking System. 43 what is DMA controller? It Facilities a multi byte data transfer or Block of data transfer between the External device & System. Modes of Operation: Single Transfer at time & then release IO bus hold on the system bus after each transfer Burst transfer at time & release of IO bus hold on the System Bus. Bulk transfer & then release of IO bus hold on the System Bus after the Transaction is Completed. 44 what is Device driver? Device driver is a program that controls a particular type of device that is attached to your computer. There are device drivers for printers, displays, CD-ROM readers, diskette drives, and so on. A device driver essentially converts the more general input/output instructions of the operating system to messages that the device type can understand. Virtual device drivers handle software interrupts from the system rather than hardware interrupts. Virtual device driver for

8 each main hardware device in the system, including the hard disk drive controller, keyboard, and serial and parallel ports.are used to maintain the status of a hardware device that has changeable settings. 45 what are the Serial Communicating Protocol? I^2 C Bus, CAN Bus, USB Bus. 46 Give Memory allocation Schemes in a system Static Memory Allocation : Allocated during Compile Time Entire space in memory is Allocated. Dynamic Memory Allocation : Allocated during Run Time.. Blocks of Memory will be allocated. 47 what are the features of USB? It can be Plugged, Configured & used, reset & Reconfigured it can Share Bandwidth with other devices,detached & Reattached. Attaching & detaching can be done without Rebooting.it can be Bus Powered or Self Powered.

EMBEDDED SYSTEM BASICS AND APPLICATION

EMBEDDED SYSTEM BASICS AND APPLICATION Dr.Syed Ajmal IIT- Robotics TOPICS TO BE DISCUSSED System Embedded System Components Classifications Processors Other Hardware Software Applications 2 INTRODUCTION