Hardware design interview questions

1. Give two ways of converting a two input NAND gate to an inverter
2. Given a circuit, draw its exact timing response. (I was given a Pseudo Random Signal Generator; you can expect any sequential ckt)
3. What are set up time & hold time constraints? What do they signify? Which one is critical for estimating maximum clock frequency of a circuit?
4. Give a circuit to divide frequency of clock cycle by two
5. Design a divide-by-3 sequential circuit with 50% duty circle. (Hint: Double the Clock)
6. Suppose you have a combinational circuit between two registers driven by a clock. What will you do if the delay of the combinational circuit is greater than your clock signal? (You can’t resize the combinational circuit transistors)
7. The answer to the above question is breaking the combinational circuit and pipelining it. What will be affected if you do this?
8. What are the different Adder circuits you studied?
9. Give the truth table for a Half Adder. Give a gate level implementation of the same.
10. Draw a Transmission Gate-based D-Latch.
11. Design a Transmission Gate based XOR. Now, how do you convert it to XNOR? (Without inverting the output)
12. How do you detect if two 8-bit signals are same?
13. How do you detect a sequence of "1101" arriving serially from a signal line?
14. Design any FSM in VHDL or Verilog.
15. Explain RC circuit’s charging and discharging.
16. Explain the working of a binary counter.
17. Describe how you would reverse a singly linked list.

Hardware and software design questions

1. What is Finite Automata
2. What is a Turing machine?
3. How many processors are there in a pentium microprocessor? In Sparc?
4. Difference between RISC and CISC
5. Is RISC always fast?
6. What is a real time system?
7. Name some real time OSs.
8. Is DOS a real time OS?
9. What is a kernel,shell?
10. What is binary search, traversal, hashing?
11. Write a code to count the no. of 1’s in a binary representation of a number.
12. Memory taken for char *, int * etc.

13. char *cp;
    int *ip;
    cp++;
    ip++;
    

    What is the result?

14. Compare the no. of bytes in unix and Dos for long, char, short, int.
15. How do you make programs portable on unix and Dos under such circumstances?
16. In C++, what is a constructor, destructor?
17. What is friend?
18. What is waterfall model, prototype model?
19. What is testing? What is unit testing, integration testing, etc?
20. What is indexing when talking about databases?
21. What is atomicity?
22. Can recursive programs be written in C++, Write a recursive program to calculate factorial

A+ and basic PC questions

1. What are the basic expansion card types?ISA and PCI, ISA can be used only on XT, AT and ATX boards. The industry now considers ISA obsolete.
2. How do you clear CMOS password? Since CMOS is a special chip with its own battery, the best way to clear out a CMOS chip is to disconnect it from its power supply.
3. Where does the Real mode on the CPU come from? The original 8086, which only had 1 MB of memory. This megabyte is split into low memory for IRQ tables, application memory and high memory.
4. Where does CPU Enhanced mode originate from? Intel’s 80386 was the first 32-bit processor, and since the company had to backward-support the 8086. All the modern Intel-based processors run in the Enhanced mode, capable of switching between Real mode (just like the real 8086) and Protected mode, which is the current mode of operation.
5. Name the processor lines of two major manufacturers? High-end: Intel - Pentium (II, III, 4), AMD - Athlon. Low-end: Intel - Celeron, AMD - Duron. 64-bit: Intel - Itanium 2, AMD - Opteron.
6. What’s the difference between L1 and L2 cache? Level 1 cache is internal to the chip, L2 is external.
7. What’s the speed and device maximum specs for Firewire? IEEE 1394 (Firewire) supports the maximum of 63 connected devices with speeds up to 400 Mbps.
8. Where’s MBR located on the disk? Main Boot Record is located in sector 0, track 0, head 0, cylinder 0 of the primary active partition.
9. What’s the maximum hard drive size for FAT16-based Windows system? 2 GB.
10. How many logical drives is it possible to fit onto a physical disk? Maximum of 24 logical drives. The extended partition can only have 23 logical drives.
11. WHat are * and ? when using them for wildcards in Windows? * - any characters, arbitrary amoung, ? - single character.
12. How does the browser know to go to a certain IP address when you enter a domain like google.com? It searches through local DNS cache, if nothing is there, it queries the ISP’s DNS server.

CCNA/Cisco admin interview questions

1. You need to retrieve a file from the file server for your word processing application, which layer of the OSI model is responsible for this function?
1. Presentation layer
2. Application layer
3. Session layer
4. Transport layer
5. Datalink layer
2. You are working in a word processing program, which is run from the file server. Your data comes back to you in an unintelligible manner. Which layer of the OSI model would you investigate?
1. Application layer
2. Presentation layer
3. Session layer
4. Network layer
5. Datalink layer
3. The IEEE subdivided the datalink layer to provide for environments that need connectionless or connection-oriented services. What are the two layers called?
1. Physical
2. MAC
3. LLC
4. Session
5. IP
4. You are working with graphic translations. Which layer of the OSI model is responsible for code formatting and conversion and graphic standards.
1. Network layer
2. Session layer
3. Transport layer
4. Presentation layer
5. Which is the best definition of encapsulation?
1. Each layer of the OSI model uses encryption to put the PDU from the upper layer into its data field. It adds header and trailer information that is available to its counterpart on the system that will receive it.
2. Data always needs to be tunneled to its destination so encapsulation must be used.
3. Each layer of the OSI model uses compression to put the PDU from the upper layer into its data field. It adds header and trailer information that is available to its counterpart on the system that will receive it.
4. Each layer of the OSI model uses encapsulation to put the PDU from the upper layer into its data field. It adds header and trailer information that is available to its counterpart on the system that will receive it.
6. Routers can be configured using several sources. Select which of the following sources can be used.
1. Console Port
2. Virtual Terminals
3. TFTP Server
4. Floppy disk
5. Removable media
7. Which memory component on a Cisco router contains the dynamic system configuration?
1. ROM
2. NVRAM
3. Flash
4. RAM/DRAM
8. Which combination of keys will allow you to view the previous commands that you typed at the router?
1. ESC-P
2. Ctrl-P
3. Shift-P
4. Alt-P
9. Which commands will display the active configuration parameters?
1. show running-config
2. write term
3. show version
4. display term
10. You are configuring a router, which prompt tells you that you are in the privileged EXEC mode?
1. @
2. >
3. !
4. :
5. #
11. What does the command “IP name-server 255.255.255.255″ accomplish?
1. It disables domain name lookup.
2. It sets the domain name lookup to be a local broadcast.
3. This is an illegal command.
4. The command is now defunct and has been replaced by “IP server-name ip any”
12. The following selections show the command prompt and the configuration of the IP network mask. Which two are correct?
1. Router(config-if)#netmask-format { bitcount | decimal | hexadecimal }
2. Router#term IP netmask-format { bitcount | decimal | hexadecimal }
3. Router(config-if)#IP netmask-format { bitcount | decimal | hexadecimal }
4. Router#ip netmask-format { bitcount | decimal | hexadecimal }
13. Which layer is responsible for flow control with sliding windows and reliability with sequence numbers and acknowledgments?
1. Transport
2. Application
3. Internet
4. Network Interface
14. Which processes does TCP, but not UDP, use?
1. Windowing
2. Acknowledgements
3. Source Port
4. Destination Port
15. Select which protocols use distance vector routing?
1. OSPF
2. RIP
3. IGRP
4. PPP

x86 interview questions

1. What is a Microprocessor? - Microprocessor is a program-controlled device, which fetches the instructions from memory, decodes and executes the instructions. Most Micro Processor are single- chip devices.
2. Give examples for 8 / 16 / 32 bit Microprocessor? - 8-bit Processor - 8085 / Z80 / 6800; 16-bit Processor - 8086 / 68000 / Z8000; 32-bit Processor - 80386 / 80486.
3. Why 8085 processor is called an 8 bit processor? - Because 8085 processor has 8 bit ALU (Arithmetic Logic Review). Similarly 8086 processor has 16 bit ALU.
4. What is 1st / 2nd / 3rd / 4th generation processor? - The processor made of PMOS / NMOS / HMOS / HCMOS technology is called 1st / 2nd / 3rd / 4th generation processor, and it is made up of 4 / 8 / 16 / 32 bits.
5. Define HCMOS? - High-density n- type Complimentary Metal Oxide Silicon field effect transistor.
6. What does microprocessor speed depend on? - The processing speed depends on DATA BUS WIDTH.
7. Is the address bus unidirectional? - The address bus is unidirectional because the address information is always given by the Micro Processor to address a memory location of an input / output devices.
8. Is the data bus is Bi-directional? - The data bus is Bi-directional because the same bus is used for transfer of data between Micro Processor and memory or input / output devices in both the direction.
9. What is the disadvantage of microprocessor? - It has limitations on the size of data. Most Microprocessor does not support floating-point operations.
10. What is the difference between microprocessor and microcontroller? - In Microprocessor more op-codes, few bit handling instructions. But in Microcontroller: fewer op-codes, more bit handling Instructions, and also it is defined as a device that includes micro processor, memory, & input / output signal lines on a single chip.
11. What is meant by LATCH? - Latch is a D- type flip-flop used as a temporary storage device controlled by a timing signal, which can store 0 or 1. The primary function of a Latch is data storage. It is used in output devices such as LED, to hold the data for display.
12. Why does microprocessor contain ROM chips? - Microprocessor contain ROM chip because it contain instructions to execute data.
13. What is the difference between primary & secondary storage device? - In primary storage device the storage capacity is limited. It has a volatile memory. In secondary storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM. Secondary devices are: Floppy disc / Hard disk.
14. Difference between static and dynamic RAM? - Static RAM: No refreshing, 6 to 8 MOS transistors are required to form one memory cell, Information stored as voltage level in a flip flop. Dynamic RAM: Refreshed periodically, 3 to 4 transistors are required to form one memory cell, Information is stored as a charge in the gate to substrate capacitance.
15. What is interrupt? - Interrupt is a signal send by external device to the processor so as to request the processor to perform a particular work.
16. What is cache memory? - Cache memory is a small high-speed memory. It is used for temporary storage of data & information between the main memory and the CPU (center processing unit). The cache memory is only in RAM.
17. What is called “Scratch pad of computer”? - Cache Memory is scratch pad of computer.
18. Which transistor is used in each cell of EPROM? - Floating –gate Avalanche Injection MOS (FAMOS) transistor is used in each cell of EPROM.
19. Differentiate between RAM and ROM? - RAM: Read / Write memory, High Speed, Volatile Memory. ROM: Read only memory, Low Speed, Non Voliate Memory.
20. What is a compiler? - Compiler is used to translate the high-level language program into machine code at a time. It doesn’t require special instruction to store in a memory, it stores automatically. The Execution time is less compared to Interpreter.
21. Which processor structure is pipelined? - All x86 processors have pipelined structure.
22. What is flag? - Flag is a flip-flop used to store the information about the status of a processor and the status of the instruction executed most recently
23. What is stack? - Stack is a portion of RAM used for saving the content of Program Counter and general purpose registers.
24. Can ROM be used as stack? - ROM cannot be used as stack because it is not possible to write to ROM.
25. What is NV-RAM? - Nonvolatile Read Write Memory, also called Flash memory. It is also know as shadow RAM.

8085 microprocessor questions

1. What are the various registers in 8085? - Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085 .
2. In 8085 name the 16 bit registers? - Stack pointer and Program counter all have 16 bits.
3. What are the various flags used in 8085? - Sign flag, Zero flag, Auxillary flag, Parity flag, Carry flag.
4. What is Stack Pointer? - Stack pointer is a special purpose 16-bit register in the Microprocessor, which holds the address of the top of the stack.
5. What is Program counter? - Program counter holds the address of either the first byte of the next instruction to be fetched for execution or the address of the next byte of a multi byte instruction, which has not been completely fetched. In both the cases it gets incremented automatically one by one as the instruction bytes get fetched. Also Program register keeps the address of the next instruction.
6. Which Stack is used in 8085? - LIFO (Last In First Out) stack is used in 8085.In this type of Stack the last stored information can be retrieved first.
7. What happens when HLT instruction is executed in processor? - The Micro Processor enters into Halt-State and the buses are tri-stated.
8. What is meant by a bus? - A bus is a group of conducting lines that carriers data, address, & control signals.
9. What is Tri-state logic? - Three Logic Levels are used and they are High, Low, High impedance state. The high and low are normal logic levels & high impedance state is electrical open circuit conditions. Tri-state logic has a third line called enable line.
10. Give an example of one address microprocessor? - 8085 is a one address microprocessor.
11. In what way interrupts are classified in 8085? - In 8085 the interrupts are classified as Hardware and Software interrupts.
12. What are Hardware interrupts? - TRAP, RST7.5, RST6.5, RST5.5, INTR.
13. What are Software interrupts? - RST0, RST1, RST2, RST3, RST4, RST5, RST6, RST7.
14. Which interrupt has the highest priority? - TRAP has the highest priority.
15. Name 5 different addressing modes? - Immediate, Direct, Register, Register indirect, Implied addressing modes.
16. How many interrupts are there in 8085? - There are 12 interrupts in 8085.
17. What is clock frequency for 8085? - 3 MHz is the maximum clock frequency for 8085.
18. What is the RST for the TRAP? - RST 4.5 is called as TRAP.
19. In 8085 which is called as High order / Low order Register? - Flag is called as Low order register & Accumulator is called as High order Register.
20. What are input & output devices? - Keyboards, Floppy disk are the examples of input devices. Printer, LED / LCD display, CRT Monitor are the examples of output devices.
21. Can an RC circuit be used as clock source for 8085? - Yes, it can be used, if an accurate clock frequency is not required. Also, the component cost is low compared to LC or Crystal.
22. Why crystal is a preferred clock source? - Because of high stability, large Q (Quality Factor) & the frequency that doesn’t drift with aging. Crystal is used as a clock source most of the times.
23. Which interrupt is not level-sensitive in 8085? - RST 7.5 is a raising edge-triggering interrupt.
24. What does Quality factor mean? - The Quality factor is also defined, as Q. So it is a number, which reflects the lossness of a circuit. Higher the Q, the lower are the losses.
25. What are level-triggering interrupt? - RST 6.5 & RST 5.5 are level-triggering interrupts.

8086 interview questions

1. What are the flags in 8086? - In 8086 Carry flag, Parity flag, Auxiliary carry flag, Zero flag, Overflow flag, Trace flag, Interrupt flag, Direction flag, and Sign flag.
2. What are the various interrupts in 8086? - Maskable interrupts, Non-Maskable interrupts.
3. What is meant by Maskable interrupts? - An interrupt that can be turned off by the programmer is known as Maskable interrupt.
4. What is Non-Maskable interrupts? - An interrupt which can be never be turned off (ie.disabled) is known as Non-Maskable interrupt.
5. Which interrupts are generally used for critical events? - Non-Maskable interrupts are used in critical events. Such as Power failure, Emergency, Shut off etc.,
6. Give examples for Maskable interrupts? - RST 7.5, RST6.5, RST5.5 are Maskable interrupts
7. Give example for Non-Maskable interrupts? - Trap is known as Non-Maskable interrupts, which is used in emergency condition.
8. What is the Maximum clock frequency in 8086? - 5 Mhz is the Maximum clock frequency in 8086.
9. What are the various segment registers in 8086? - Code, Data, Stack, Extra Segment registers in 8086.
10. Which Stack is used in 8086? - FIFO (First In First Out) stack is used in 8086.In this type of Stack the first stored information is retrieved first.
11. What are the address lines for the software interrupts? -
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

    RST 0	0000 H
    RST1	0008 H
    RST2	0010 H
    RST3	0018 H
    RST4	0020 H
    RST5	0028 H
    RST6	0030 H
    RST7	0038 H

12. What is SIM and RIM instructions? - SIM is Set Interrupt Mask. Used to mask the hardware interrupts. RIM is Read Interrupt Mask. Used to check whether the interrupt is Masked or not.
13. Which is the tool used to connect the user and the computer? - Interpreter is the tool used to connect the user and the tool.
14. What is the position of the Stack Pointer after the PUSH instruction? - The address line is 02 less than the earlier value.
15. What is the position of the Stack Pointer after the POP instruction? - The address line is 02 greater than the earlier value.
16. Logic calculations are done in which type of registers? - Accumulator is the register in which Arithmetic and Logic calculations are done.
17. What are the different functional units in 8086? - Bus Interface Unit and Execution unit, are the two different functional units in 8086.
18. Give examples for Micro controller? - Z80, Intel MSC51 &96, Motorola are the best examples of Microcontroller.
19. What is meant by cross-compiler? - A program runs on one machine and executes on another is called as cross-compiler.
20. What are the address lines for the hardware interrupts? -
    
    
    
    
    
    
    
    
    
    

    RST 7.5	003C H
    RST 6.5	0034 H
    RST 5.5	002C H
    TRAP	0024 H

21. Which Segment is used to store interrupt and subroutine return address registers? - Stack Segment in segment register is used to store interrupt and subroutine return address registers.
22. Which Flags can be set or reset by the programmer and also used to control the operation of the processor? - Trace Flag, Interrupt Flag, Direction Flag.
23. What does EU do? - Execution Unit receives program instruction codes and data from BIU, executes these instructions and store the result in general registers.
24. Which microprocessor accepts the program written for 8086 without any changes? - 8088 is that processor.
25. What is the difference between 8086 and 8088? - The BIU in 8088 is 8-bit data bus & 16- bit in 8086.Instruction queue is 4 byte long in 8088and 6 byte in 8086.

Large list of Intel interview questions

1. Insights of an inverter. Explain the working?
2. Insights of a 2 input NOR gate. Explain the working?
3. Insights of a 2 input NAND gate. Explain the working?
4. Implement F= not (AB+CD) using CMOS gates?
5. Insights of a pass gate. Explain the working?
6. Why do we need both PMOS and NMOS transistors to implement a pass gate?
7. What does the above code synthesize to?
8. Cross section of a PMOS transistor?
9. Cross section of an NMOS transistor?
10. What is a D-latch? Write the VHDL Code for it?
11. Differences between D-Latch and D flip-flop?
12. Implement D flip-flop with a couple of latches? Write a VHDL Code for a D flip-flop?
13. What is latchup? Explain the methods used to prevent it?
14. What is charge sharing?
15. While using logic design, explain the various steps that r followed to obtain the desirable design in a well defined manner?
16. Why is OOPS called OOPS? (C++)
17. What is a linked list? Explain the 2 fields in a linked list?
18. Implement a 2 I/P and gate using Tran gates?
19. Insights of a 4bit adder/Sub Circuit?
20. For f = AB+CD if B is S-a-1, what r the test vectors needed to detect the fault?
21. Explain various adders and diff between them?
22. Explain the working of 4-bit Up/down Counter?
23. A circuit has 1 input X and 2 outputs A and B. If X = HIGH for 4 clock ticks, A = 1. If X = LOW for 4 clock ticks, B = 1. Draw a state diagram for this Spec?
24. Advantages and disadvantages of Mealy and Moore?
25. Id vs. Vds Characteristics of NMOS and PMOS transistors?
26. Explain the operation of a 6T-SRAM cell?
27. Differences between DRAM and SRAM?
28. Implement a function with both ratioed and domino logic and merits and demerits of each logic?
29. Given a circuit and asked to tell the output voltages of that circuit?
30. How can you construct both PMOS and NMOS on a single substrate?
31. What happens when the gate oxide is very thin?
32. What is setup time and hold time?
33. Write a pseudo code for sorting the numbers in an array?
34. What is pipelining and how can we increase throughput using pipelining?
35. Explain about stuck at fault models, scan design, BIST and IDDQ testing?
36. What is SPICE?
37. Differences between IRSIM and SPICE?
38. Differences between netlist of HSPICE and Spectre?
39. What is FPGA?
40. Draw the Cross Section of an Inverter? Clearly show all the connections between M1 and poly, M1 and diffusion layers etc?
41. Draw the Layout of an Inverter?
42. If the current thru the poly is 20nA and the contact can take a max current of 10nA how would u overcome the problem?
43. Implement F = AB+C using CMOS gates?
44. Working of a 2-stage OPAMP?
45. 6-T XOR gate?
46. Differences between blocking and Non-blocking statements in Verilog?
47. Differences between Signals and Variables in VHDL? If the same code is written using Signals and Variables what does it synthesize to?
48. Differences between functions and Procedures in VHDL?
49. What is component binding?
50. What is polymorphism? (C++)
51. What is hot electron effect?
52. Define threshold voltage?
53. Factors affecting Power Consumption on a chip?
54. Explain Clock Skew?
55. Why do we use a Clock tree?
56. Explain the various Capacitances associated with a transistor and which one of them is the most prominent?
57. Explain the Various steps in Synthesis?
58. Explain ASIC Design Flow?
59. Explain Custom Design Flow?
60. Why is Extraction performed?
61. What is LVS, DRC?
62. Who provides the DRC rules?
63. What is validation?
64. What is Cross Talk?
65. Different ways of implementing a comparator?
66. What r the phenomenon which come into play when the devices are scaled to the sub-micron lengths?
67. What is clock feed through?
68. Implement an Inverter using a single transistor?
69. What is Fowler-Nordheim Tunneling?
70. Insights of a Tri-state inverter?
71. If an/ap = 0.5, an/ap = 1, an/ap = 3, for 3 inverters draw the transfer characteristics?
72. Differences between Array and Booth Multipliers?
73. Explain the concept of a Clock Divider Circuit? Write a VHDL code for the same?
74. Which gate is normally preferred while implementing circuits using CMOS logic, NAND or NOR? Why?
75. Insights of a Tri-State Inverter?
76. Basic Stuff related to Perl?
77. Have you studied buses? What types?
78. Have you studied pipelining? List the 5 stages of a 5 stage pipeline. Assuming 1 clock per stage, what is the latency of an instruction in a 5 stage machine? What is the throughput of this machine ?
79. How many bit combinations are there in a byte?
80. For a single computer processor computer system, what is the purpose of a processor cache and describe its operation?
81. Explain the operation considering a two processor computer system with a cache for each processor.
82. What are the main issues associated with multiprocessor caches and how might you solve them?
83. Explain the difference between write through and write back cache.
84. Are you familiar with the term MESI?
85. Are you familiar with the term snooping?
86. Describe a finite state machine that will detect three consecutive coin tosses (of one coin) that results in heads.
87. In what cases do you need to double clock a signal before presenting it to a synchronous state machine?
88. You have a driver that drives a long signal & connects to an input device. At the input device there is either overshoot, undershoot or signal threshold violations, what can be done to correct this problem?
89. What are the total number of lines written by you in C/C++? What is the most complicated/valuable program written in C/C++?
90. What compiler was used?
91. What is the difference between = and == in C?
92. Are you familiar with VHDL and/or Verilog?
93. What types of CMOS memories have you designed? What were their size? Speed?
94. What work have you done on full chip Clock and Power distribution? What process technology and budgets were used?
95. What types of I/O have you designed? What were their size? Speed? Configuration? Voltage requirements?
96. Process technology? What package was used and how did you model the package/system? What parasitic effects were considered?
97. What types of high speed CMOS circuits have you designed?
98. What transistor level design tools are you proficient with? What types of designs were they used on?
99. What products have you designed which have entered high volume production?
100. What was your role in the silicon evaluation/product ramp? What tools did you use?
101. If not into production, how far did you follow the design and why did not you see it into production?

Electrical engineer interview questions

1. What types of CMOS memories have you designed? What were their size? Speed? Configuration Process technology?
2. What work have you done on full chip Clock and Power distribution? What process technology and budgets were used?
3. What types of I/O have you designed? What were their size? Speed? Configuration? Voltage requirements? Process technology? What package was used and how did you model the package/system? What parasitic effects were considered?
4. What types of high speed CMOS circuits have you designed?
5. What transistor level design tools are you proficient with? What types of designs were they used on?
6. What products have you designed which have entered high volume production?
7. What was your role in the silicon evaluation/product ramp? What tools did you use?
8. If not into production, how far did you follow the design and why did not you see it into production?

Embedded firmware interview questions

• Write function in C that gets array of chars, and search for the longest sequence of repeatedly 1 bits. It returns the the first bit place in the sequence and the number of 1 bits in the sequence. - (a) loop of 2^0, 2^1, … , 2^7 is done with 1<
• You have 16bit register that increment itself and loops about every second. When the register reach 0xffff it will issue an interupt and will run the function update_time(). There is a function unsigned long get_time() that returns the time. You need to implement the two functions. - (a) You need to count every interrupt in order to save the number of seconds. (b) The counter will be the 16bit MSB, and the actual register will be 16bit LSB. (c) If the register will be at ~0xfff0, you will return MSB that is not correct, because you will read the counter, then interrupt will accure and increment by one. Now you have counter that is not correct. (d) You need to check for the (c) problem, and if you catch the problem, you need to read once again the register and the counter before you return them. You depend on the fact the you have about another second until the register will loop.

Electronic engineer interview questions

1. What is D-FF?
2. What is the basic difference between Latches and Flip flops?
3. What is a multiplexer?
4. How can you convert an SR Flip-flop to a JK Flip-flop?
5. How can you convert an JK Flip-flop to a D Flip-flop?
6. What is Race-around problem? How can you rectify it?
7. Which semiconductor device is used as a voltage regulator and why?
8. Explain an ideal voltage source?
9. Explain zener breakdown and avalanche breakdown?
10. What are the different types of filters?
11. What is the need of filtering ideal response of filters and actual response of filters?
12. What is sampling theorem?
13. What is impulse response?
14. Explain the advantages and disadvantages of FIR filters compared to IIR counterparts.
15. What is CMRR?
16. Explain half-duplex and full-duplex communication?
17. Which range of signals is used for terrestrial transmission?
18. Why is there need for modulation?
19. Which type of modulation is used in TV transmission?
20. Why we use vestigial side band (VSB-C3F) transmission for picture?
21. When transmitting digital signals is it necessary to transmit some harmonics in addition to fundamental frequency?
22. For asynchronous transmission, is it necessary to supply some synchronizing pulses additionally or to supply or to supply start and stop bit?
23. BPFSK is more efficient than BFSK in presence of noise. Why?
24. What is meant by pre-emphasis and de-emphasis?
25. Explain 3 dB cutoff frequency? Why is it 3 dB, not 1 dB?
26. Explain ASCII, EBCDIC?

CPU engineer interview questions

1. For a single computer processor computer system, what is the purpose of a processor cache and describe its operation?
2. Explain the operation considering a two processor computer system with a cache for each processor.
3. What are the main issues associated with multiprocessor caches and how might you solve it?
4. Explain the difference between write through and write back cache.
5. Are you familiar with the term MESI?
6. Are you familiar with the term snooping?
7. Describe a finite state machine that will detect three consecutive coin tosses (of one coin) that results in heads.
8. In what cases do you need to double clock a signal before presenting it to a synchronous state machine?
9. You have a driver that drives a long signal and connects to an input device. At the input device there is either overshoot, undershoot or signal threshold violations, what can be done to correct this problem?

C questions for a hardware engineer

1. What are the total number of lines written in C/C++? What is the most complicated/valuable program written in C/C++?
2. What compiler was used?
3. Have you studied buses? What types?
4. Have you studied pipelining? List the 5 stages of a 5 stage pipeline. Assuming 1 clock per stage, what is the latency of an instruction in a 5 stage machine? What is the throughput of this machine ?
5. How many bit combinations are there in a byte?
6. What is the difference between = and == in C?
7. Are you familiar with VHDL and/or Verilog?

Hardware architecture interview questions

1. Are you familiar with the term MESI?
2. Are you familiar with the term snooping?
3. Describe a finite state machine that will detect three consecutive coin tosses (of one coin) that results in heads.
4. In what cases do you need to double clock a signal before presenting it to a synchronous state machine?
5. You have a driver that drives a long signal & connects to an input device. At the input device there is either overshoot, undershoot or signal threshold violations, what can be done to correct this problem?
6. For a single computer processor computer system, what is the purpose of a processor cache and describe its operation?
7. Explain the operation considering a two processor computer system with a cache for each processor.
8. What are the main issues associated with multiprocessor caches and how might you solve it?
9. Explain the difference between write through and write back cache.
10. What are the total number of lines written in C/C++? What is the most complicated/valuable program written in C/C++?
11. What compiler was used?
12. Have you studied busses? What types?
13. Have you studied pipelining? List the 5 stages of a 5 stage pipeline. Assuming 1 clock per stage, what is the latency of an instruction in a 5 stage machine? What is the throughput of this machine ?
14. How many bit combinations are there in a byte?
15. What is the difference between = and == in C?
16. Are you familiar with VHDL and/or Verilog?

8086 interview questions

1. How many bits does 8086 microprocessor have?
2. What is the size of data bus in 8086?
3. What is the size of address bus in 8086?
4. What is the max memory addressing capacity of 8086?
5. Which are the basic parts of 8086?
6. What are the functions of BIU?
7. What are the functions of EU?
8. How many pin IC 8086 is?
9. What IC8086 is?
10. What is the size of instruction queue in 8086?
11. What is the size of instruction queue in 8088?
12. Which are the registers present in 8086?
13. What is pipelining in 8086?
14. How many 16 bit registers are available in 8086?
15. Specify addressing modes for any instruction?
16. What is assembler directives?
17. What .model small stands for?
18. What is the supply requirement of 8086?
19. What is the relation between 8086 processor frequency & crystal frequency?
20. Functions of Accumulator or AX register?
21. Functions of BX register?
22. Functions of CX register?
23. Functions of DX register?
24. How Physical address is generated?
25. Which are pointers present in this 8086?
26. Which is by default pointer for CS/ES?
27. How many segments present in it?
28. What is the size of each segment?
29. Basic difference between 8085 and 8086?
30. Which operations are not available in 8085?
31. What is the difference between min mode and max mode of 8086?
32. What is the difference between near and far procedure?
33. What is the difference between Macro and procedure?
34. What is the difference between instructions RET & IRET?
35. What is the difference between instructions MUL & IMUL?
36. What is the difference between instructions DIV & IDIV?
37. What is difference between shifts and rotate instructions?
38. Which are strings related instructions?
39. Which are addressing modes and their examples in 8086?
40. What does u mean by directives?
41. What does u mean by Prefix?
42. What .model small means?
43. Difference between small, medium, tiny, huge?
44. What is dd, dw, db?
45. Interrupts in 8086 and there function.
46. What is the function of 01h of Int 21h?
47. What is the function of 02h of Int 21h?
48. What is the function of 09h of Int 21h?
49. What is the function of 0Ah of Int 21h?
50. What is the function of 4ch of Int 21h?
51. What is the reset address of 8086?
52. What is the size of flag register in 8086? Explain all.
53. What is the difference between 08H and 01H functions of INT 21H?
54. Which is faster- Reading word size data whose starting address is at even or at odd address of memory in 8086?
55. Which are the default segment base: offset pairs?
56. Can we use SP as offset address holder with CS?
57. Which are the base registers in 8086?
58. Which is the index registers in 8086?
59. What is segment override prefix?
60. Whether micro reduces memory requirements?
61. What is macro?
62. What is diff between macro and procedure?
63. Types of procedure?
64. What TASM is?
65. What TLINK is?
66. What TD is?
67. What do u mean by assembler?
68. What do u mean by linker?
69. What do u mean by loader?
70. What do u mean by compiler?
71. What do u mean by emulator?
72. Stack related instruction?
73. .stack 100 means?
74. What is 20 dup (0)?
75. Which flags of 8086 are not present in 8085?
76. What is the size of flag register?
77. Can you perform 32 bit operation with 8086? How?
78. Whether 8086 is compatible with Pentium processor?
79. What is 8087? How it is different from 8086?
80. While accepting no. from user why u need to subtract 30 from that?
81. While displaying no. from user why u need to add 30 to that?
82. What are ASCII codes for nos. 0 to F?
83. How does U differentiate between positive and negative numbers?
84. What is range for these numbers?
85. Which no. representation system you have used?
86. What is LEA?
87. What is @data indicates in instruction- MOV ax, @data?
88. What is maximum size of the instruction in 8086?
89. Why we indicate FF as 0FF in program?
90. What is mul BX and div BX? Where result goes?
91. Where queue is present?
92. What is the advantage of using internal registers?
93. What is SI, DI and their functions?
94. Which are the pointers used in 8086 and their functions?
95. What is a type of queue in 8086?
96. What is minimum mode of 8086?
97. What is maximum mode of 8086?
98. Which are string instructions?
99. In string operations which is by default string source pointer?
100. In string operations which is by default string destination pointer?

8251 USART interview questions

1. What is IC 8251?
2. How many pins does IC 8251 have?
3. What is USART?
4. Why 8251 is called a USART?
5. What is simplex half & full duplex modes of communication?
6. What is the difference between asynchronous & synchronous mode of communication?
7. Explain control word format of 8251?
8. Define frame in asynchronous communication and draw it.
9. Define baud rate.
10. Define bit rate.
11. Define mode word register of 8251 for asynchronous mode..
12. Define mode word register of 8251 for sync mode..
13. What is the significance of SYNC DETECT signal in 8251?
14. What is the significance of BREAK DETECT signal in 8251?
15. Define command word register of 8251.
16. Define status word register of 8251.
17. What are the applications of 8251?
18. Whether write operation is possible with status word register?
19. Whether operation read is possible with command word register?
20. What is parity error in 8251?
21. What is over run error in 8251?
22. What is frame error in 8251?
23. What is hunt mode in 8251?
24. Explain block diagram IC 8251?
25. Explain the logic of 8251 program.
26. Explain the interfacing of 8251 with 8086.

IC 8253 and IC 8259 interview questions

1. What is IC 8253?
2. How many pins does IC 8253 have?
3. How many counters are there in 8253?
4. What is the size of counters in 8253?
5. With binary & BCD counters, what is the range of count?
6. Explain control word format of 8253?
7. Define & explain mode ‘0′ of 8253?
8. Define & explain mode ‘1′ of 8253?
9. Define & explain mode ‘2′ of 8253?
10. Define & explain mode ‘3′ of 8253?
11. Define & explain mode ‘4′ of 8253?
12. Define & explain mode ‘5′ of 8253?
13. What is the difference between software and hardware triggered modesof 8253?
14. What is the difference between 8253 and 8254?
15. What is read back command in 8254?
16. What are the applications of 8253?
17. Explain block diagram IC 8253?
18. Explain the logic of 8253 program.
19. Explain the interfacing of 8253 with 8086.
20. What is IC 8259?
21. How many pins does IC 8259 have?
22. Explain all initialization and operational command word format of 8259?
23. With single 8259 how many interrupts are possible?
24. With cascading mode of 8259 how many interrupts are possible?
25. How many 8259 ICs will be required for cascading mode?
26. What is the difference between polled command mode and vectored (interrupt driven) command mode of 8259?
27. What are the applications of 8259?

DAC interview questions

1. What is the IC numbers for DAC that you have used in the lab?
2. Define resolution. What is the resolution of DAC that you have used in the lab?
3. How many pins does DAC IC have?
4. What are the types of DAC?
5. Which technique you have used for DAC interfacing
6. Which type of DAC you have used in the lab?
7. Define all the specifications of DAC.
8. What are the advantages of binary ladder type DAC over weighted resistance type DAC?
9. What are the applications of DAC?
10. Explain block diagram IC 0808?
11. Explain the logic of DAC program.
12. Explain the interfacing of DAC with 8086.