Using an asynchronous reset, the designer is guaranteed not to have the reset added to the data path. Another advantage favoring asynchronous resets is that the circuit can be reset with or without a clock present.
Ensure that the release of the reset can occur within one clock period else if the release of the reset occurred on or near a clock edge then flip-flops may go into metastable state. What Is A Johnson Counter? Answer : Johnson counter connects the complement of the output of the last shift register to its input and circulates a stream of ones followed by zeros around the ring.
For example, in a 4-register counter, the repeating pattern is: , , , , , , , , so on. Answer : Flip-flops are edge-sensitive devices where as latches are level sensitive devices.
Flip-flops are immune to glitches where are latches are sensitive to glitches. Latches require less number of gates and hence less power than flip-flops.
Latches are faster than flip-flops. Answer : Mealy FSM uses only input actions, i. The use of a Mealy FSM leads often to a reduction of the number of states. Moore FSM uses only entry actions, i. The advantage of the Moore model is a simplification of the behavior. Explain Them? Answer : One-Hot encoding: Each state is represented by a bit flip-flop. If there are four states then it requires four bits four flip-flops to represent the current state. The valid state values are , , , and If the value is , then it means second state is the current state.
One-Cold encoding: Same as one-hot encoding except that '0' is the valid value. Binary encoding: Each state is represented by a binary code. Gray encoding: Each state is represented by a Gray code. Answer : Clock skew is a phenomenon in synchronous circuits in which the clock signal sent from the clock circuit arrives at different components at different times. This can be caused by many different things, such as wire-interconnect length, temperature variations, variation in intermediate devices, capacitive coupling, material imperfections, and differences in input capacitance on the clock inputs of devices using the clock.
There are two types of clock skew: negative skew and positive skew. Positive skew occurs when the clock reaches the receiving register later than it reaches the register sending data to the receiving register. Negative skew is the opposite: the receiving register gets the clock earlier than the sending register. Define Metastability?
Answer : If there are setup and hold time violations in any sequential circuit, it enters a state where its output is unpredictable, this state is known as metastable state or quasi stable state, at the end of metastable state, the flip-flop settles down to either logic high or logic low. Whenever there are setup and hold time violations in any flip-flop, it enters a state where its output is unpredictable, which is known as as metastable state or quasi stable state.
At the end of metastable state, the flip-flop settles down to either logic high or logic low. What Are Pla And Pal? Give The Differences Between Them? Answer : Programmable Logic Array is a programmable device used to implement combinational logic circuits. The PLA has a set of programmable AND planes, which link to a set of programmable OR planes, which can then be conditionally complemented to produce an output.
Due to fixed OR plane PAL allows extra space, which is used for other basic logic devices, such as multiplexers, exclusive-ORs, and latches.
Most importantly, clocked elements, typically flip-flops, could be included in PALs. PALs are also extremely fast. An n-bit look-up table can be implemented with a multiplexer whose select lines are the inputs of the LUT and whose inputs are constants. An n-bit LUT can encode any n-input Boolean function by modeling such functions as truth tables.
This helps for faster and cheaper testing. Once the logic is verified then they are made into ASICs. Very useful in applications that can make use of the massive parallelism offered by their architecture. Example: code breaking, in particular brute-force attack, of cryptographic algorithms. Applications include digital signal processing, software-defined radio, aerospace and defense systems, medical imaging, computer vision, speech recognition, cryptography, bio-informatics, computer hardware emulation and a growing range of other areas.
Popular Interview Questions. All Interview Questions. Digital Logic Design Practice Test. IT Skills. Management Skills. Communication Skills. Business Skills. Digital Marketing Skills. Human Resources Skills. Health Care Skills. Finance Skills. All Courses.
All Practice Tests. Web Designing Interview Questions Question 3. What Is Slack? After the time required to access the memory elapses, the addressed word in this case, the first instruction of the program is read out of the memory and loaded into the MDR. At this point, the instruction is ready to be decoded and executed.
If the instruction involves an operation to be performed by the ALU, it is necessary to obtain the required operands. If an operand resides in memory it could also be in a generalpurpose register in the processor , it has to be fetched by sending its address to the MAR and initiating a Read cycle.
After one or more operands are fetched in this way, the ALU can perform the desired operation. If the result of the operation is to be stored in the memory, then the result is sent to the MDR. The address of the location where the result is to be stored is sent to the MAR, and a write cycle is initiated. At some point during the execution of the current instruction, the contents of the PC are incremented so that the PC points to the next instruction to be executed. Thus, as soon as the execution of the current instruction is completed, a new instruction fetch may be started.
In addition to transferring data between the memory and the processor, the computer accepts data from input devices and sends data to output devices. UI Developer Interview Questions Normal execution of a programs may be preempted if some device requires urgent servicing. For example, a monitoring device in a computer-controlled industrial process may detect a dangerous condition.
In order to deal with the situation immediately, the normal execution of the current program must be interrupted. To do this, the device raises an interrupt signal. The processor provides the requested service by executing an appropriate interrupt-service routine.
Because such diversions may alter the internal state of the processor, its state must be saved in the memory locations before servicing the interrupt. Normally, the contents of the PC, the general registers, and some control information are stored in memory. When the interrupt service routine is completed, the state of the processor is restored so that the interrupted program may continue.
CSS3 Interview Questions Elapsed time: The total time required to execute a program. This elapsed time is a measure of the performance of the entire computer system.
It is affected by the speed of the processor, the disk and the printer. Processor time: Here we have to consider only those periods of the elapsed time, during which the processor is active.
The sum of these periods is called processor time. The processor time depends on the hardware involved in the execution of individual machine instructions.
Cache memory: The processor and a relatively small cache memory can be fabricated on a single IC chip. The internal speed of performing the basic steps of instruction processing on such chips is very high and considerably faster than the speed at which instructions and data can be fetched from the main memory. A program will be executed faster if the movement of instructions and data between the main memory and processor is minimized, which is achieved by using the cache.
CSS Advanced Tutorial System software is responsible for the coordination of all activities in a computing system. System software is a collection of programs that are executed as needed to perform functions such as Receiving and interpreting user commands. Entering and editing application programs and storing them as files in secondary storage devices. Managing the storage and retrieval of files in secondary storage devices.
Running standard application programs such as word processors, spread sheets, or games, with data supplied by the user. Translating programs from high level language to low level language. State Reduction b. State Minimization c. State Assignment d. Please can u sent this questions in pdf to my mail : a.
HI sir, This is very nice question. Can u send me alli pdf file on my mail id. In Question No. Your email address will not be published. Storage of 1 KB means the following number of bytes a b c d Ans:c 3. Ans:b 4. Ans:c 5. Ans:b 7. Ans:c 8. Ans:a 9.
Ans:d The number of Boolean functions that can be generated by n variables is equal to a 2n b 22 n c 2n-1 d — 2n Ans:b The number of input words in its truth table are a 6 b 32 c 64 d Ans:c Ans:c Ans:b Ans:a The binary number is equivalent to decimal number …………..
The universal gate is ……………… a. NAND gate b. OR gate c. AND gate d. None of the above Answer : a The inverter is …………… a.
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