Some common Interview Questions on Microprocessors

• Which type of architecture 8085 has?
• How many memory locations can be addressed by a microprocessor with 14 address lines?
• 8085 is how many bit microprocessor?
• Why is data bus bi-directional?
• What is the function of accumulator?
• What is flag, bus?
• What are tri-state devices and why they are essential in a bus oriented system?
• Why are program counter and stack pointer 16-bit registers?
• What does it mean by embedded system?
• What are the different addressing modes in 8085?
• What is the difference between MOV and MVI?
• What are the functions of RIM, SIM, IN?
• What is the immediate addressing mode?
• What are the different flags in 8085?
• What happens during DMA transfer?
• What do you mean by wait state? What is its need?
• What is PSW?What is ALE? Explain the functions of ALE in 8085.
• What is a program counter? What is its use?
• What is an interrupt?
• Which line will be activated when an output device require attention from CPU?

Pentium Processor Family : A Brief

The Pentium family of processors, which has its roots in the Intel486(TM) processor, uses the Intel486 instruction set (with a few additional instructions). The term ''Pentium processor'' refers to a family of microprocessors that share a common architecture and instruction set. The first Pentium processors (the P5 variety) were introduced in 1993. This 5.0-V processor was fabricated in 0.8-micron bipolar complementary metal oxide semiconductor (BiCMOS) technology. The P5 processor runs at a clock frequency of either 60 or 66 MHz and has 3.1 million transistors.
The next version of the Pentium processor family, the P54C processor, was introduced in 1994. The P54C processors are fabricated in 3.3-V, 0.6-micron BiCMOS technology. The P54C processor also has System Management Mode (SMM) for advanced power management
The Intel Pentium processor, like its predecessor the Intel486 microprocessor, is fully software compatible with the installed base of over 100 million compatible Intel architecture systems. In addition, the Intel Pentium processor provides new levels of performance to new and existing software through a reimplementation of the Intel 32-bit instruction set architecture using the latest, most advanced, design techniques. Optimized, dual execution units provide one-clock execution for "core" instructions, while advanced technology, such as superscalar architecture, branch prediction, and execution pipelining, enables multiple instructions to execute in parallel with high efficiency. Separate code and data caches combined with wide 128-bit and 256-bit internal data paths and a 64-bit, burstable, external bus allow these performance levels to be sustained in cost-effective systems. The application of this advanced technology in the Intel Pentium processor brings "state of the art" performance and capability to existing Intel architecture software as well as new and advanced applications.
The Pentium processor has two primary operating modes and a "system management mode."
The operating mode determines which instructions and architectural features are accessible.

How does Microprocessor work?

Microprocessors have become the movers and shakers of our everyday world. We use them in computers, televisions, watches, microwaves and practically every other electronic device. Their micro-size is no reflection of the myriad capabilities these chips possess, ranging from 2 to 3 mm square to maybe an inch thick. Silicon makes up the material of a microprocessor chip. Sliced wafer thin, silicon serves as an ideal conductor and insulator for transmitting electrical currents throughout the components of the chip. The finished product is an integrated circuit composed of layers of built-in wiring and transistors. Through the use of laser light, circuit outlines are etched onto a silicon surface through a mask or stencil design. A simple chip can have as many as 3,000 transistors, with as narrow a spacing of 60 nanometers between each one.

A microprocessor is the central processing unit in a computer. It receives, transmits and coordinates every command and process carried out by the system. Electrical currents, moving through wires and transistors, are converted into usable messages through the use of a Boolean logic language. Based on the "on/off" frequency of current moving through transistor circuits, this Boolean logic communicates system commands to and from receiving devices within the computer. The microprocessor communicates within two primary capacities: logic and the processing of information. These processes are handled by two components within the chip:

• Arithmetic logic unit (ALU), responsible for all commands requiring an arithmetic or logic function
• Control unit (CU), which handles the information processing from the computer's memory From these units within the chip, clusters of wires called "bus" lines send and receive information to and from system devices.

Potential

The first microprocessor chip was designed in 1974. Since that time, technological advancements continue to reduce the size requirements of chips while doubling their processing capability. This continued progress has made for a more efficient unit, and material costs have gone down considerably. The next step toward further development lies within the field of nanotechnology. This field works within the molecular/subatomic realm of science. Its purpose is to rebuild the most basic of materials--atoms and molecules--from the ground up. Currently, nanotechnologists are working to replicate the microprocessor chip model on a molecular scale. Once completed, information-processing capabilities will dwarf our current processing abilities. These improvements are expected to radically alter technology as we know it today.

What is Microproessor

A microprocessor is a computer processor on a microchip. It's sometimes called a logic chip. It is the "engine" that goes into motion when you turn your computer on. A microprocessor is designed to perform arithmetic and logic operations that make use of small number-holding areas called registers. Typical microprocessor operations include adding, subtracting, comparing two numbers, and fetching numbers from one area to another. These operations are the result of a set of instructions that are part of the microprocessor design. When the computer is turned on, the microprocessor is designed to get the first instruction from the basic input/output system (BIOS) that comes with the computer as part of its memory. After that, either the BIOS, or the operating system that BIOS loads into computer memory, or an application progam is "driving" the microprocessor, giving it instructions to perform.