Page 1 :
TIMING DIAGRAM for various machine cycles, , The machine cycles are the basic operations performed by the processor, while instructions, are executed. The time taken for performing each machine cycle is expressed in terms of Tstates., , One T-state is the time period of one clock cycle of the microprocessor,, , The various machine cycles are, , 1, Opcode fetch... - 4/6T, 2, Memory Read ...........004. -3T, , 3, Memory Write 0... eee -3T, , 4, TO REM siscnensresnncenn -3T, , 5, WO Write scssersievsevnaveeness -3T, , 6. Interrupt Acknowledge ...... - 6/12T, , Fi BOs Me sosssvsvvnnssononssnnss - 2/3T

Page 2 :
Instruction cycle, , e Instruction: A command given to the microprocessor, to perform an operation, , e Program : A set of instructions given in a sequential, manner to perform a particular task, , The CPU fetches one instruction from memory, at a time & executes it., , Instruction cycle = Fetch cycle + Execute cycle

Page 3 :
Fetch Cycle : The steps taken by CPU to fetch the, opcode from the memory, , The time taken for fetch cycle is fixed., , Execute Cycle : The steps taken by CPU to fetch data, & to perform the operation specified in the instruction, , The time taken for execute cycle is variable which, depends on the type of instruction ,i.e. 3 —byte , 2-byte, & |-byte instruction.

Page 4 :
Machine cycle, , The time required by the micro processor to complete, the operation of accessing memory or I/O device ., , Operations like :, * Opcode fetch, » Memory read, * Memory write, > I/O read, > I/O write

Page 5 :
T - states, , Microprocessor performs an operation in specific clock, cycles., , Each clock cycle is called as T —States., , The number of T — states required to perform an, operation is called Machine Cycle .