In microprocessors, the IC (instruction cycle), FC (fetch cycle) and EC (execution cycle) are related as

Question

Question

This question was previously asked in

ESE Electrical 2015 Paper 2: Official Paper

Attempt Online

Answer 1

The Steps required by the CPU to fetch and execute an Instruction is called an instruction cycle. It consists of fetch and executes cycle.
Instruction cycle (IC) = Fetch cycle (FC) + Execution cycle (EC)
The time required by the microprocessor to complete the operation of accessing memory or I/O devices is called a machine cycle.
Clock time is a known time state. It is reciprocal of clock frequency.
Instruction cycle > Machine cycle > Clock cycle (time state)

26 June 1

Steps in the instruction cycle:

First of all, the opcode is fetched by the microprocessor from a stored memory location.
Then it is decoded by the microprocessor to find out which operation it needs to perform.
If an instruction contains data or operand address which is still in the memory, the CPU has to perform read operation to get the desired data.
After receiving the data, it performs to execute the operation.

Correct sequence: fetch → decode → read effective address → execute