03-10-2012, 11:21 AM
MICROPROCESSOR & MICROCONTROLLER INTERVIEW QUESTION
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1. What is microprocessor?
It is a program controlled semi conductor device (IC), which fetches,
decodes and execute instructions.
2. What are the basic units of microprocessor?
The basic units or blocks of microprocessor are ALU, an array of registers
and control unit.
3. What is a bus?
Bus is a group of conducting lines that carries data, address and control
signals.
4. Why data bus is bi-directional?
The microprocessor is to fetch (read) the data from memory or input device
for processing and after processing it has to store (write) the data to memory or output
devices. Hence the data bus is bi-directional.
5. Why data bus is bi-directional?
The address is an identification number used by the microprocessor to
identify or access a memory location or input/output device. It is an output signal
from the processor. Hence the address bus is unidirectional.
6. Define machine cycle?
Machine cycle is defined as the time required to complete one operation of
accessing memory input/output, or acknowledging an external request. This cycle
may consists of three to six T-states.
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7. Define T-state?
T-state is defined as one subdivision of operation performed in one clock
period. These subdivisions are internal states synchronized with the system clock, and
each T-state is precisely equal to one clock period.
8. What is an instruction cycle?
The sequence of operations that a processor has to carry out while
executing the instruction is called instruction cycle. Each instruction cycle of
processor contains a number of machine cycles.
9. What is fetch and execute cycle?
The instruction cycle is divided in to fetch and execute cycles. The fetch
cycle is executed to fetch the opcode from memory. The execute cycle is executed to
decode the instruction and to perform the work instructed by the instruction.
10. List the flags of 8085?
There are five flags in 8085.They are sign flag, zero flag, auxiliary carry
flag, parity flag and carry flag.