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How many t states are required for opcode fetch machine cycle at the execution of sequential instruction?
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What is an instruction phase together with the execution phase called?
The instruction phase together with the execution phase is called a "Machine Cycle".
What is a cycling machine?
Each time the CPU executes an instruction, it takes a series of steps. The complete series of steps is called a machine cycle. A machine cycle can be divided into two smaller cycles. These are instruction cycle and execution cycle. Instruction cycle: In instruction cycle CPU takes two steps-- 1. Fetching: Before the CPU can execute an instruction, the control unit must retrieve or fetch a command or data from the computer's memory. 2. Decoding: Before a command can be executed, the control unit must decode the command into instruction set. Execution cycle: In execution cycle CPU also takes two steps-- 1. Executing: When the command is executed, the CPU carried out the instructions in order by converting them into macrocode. 2. Storing: The CPU may be required to store the result of an instruction in memory.
What is the use crystal 11.0592MHZ?
this crystals deter mains how many no of machine cycles are need for the execution of one instruction
What is a micro-instruction?
microinstruction: An instruction that controls data flow and instruction-execution sequencing in a processor at a more fundamental level than machine instructions. Note: A series of microinstructions is necessary to perform an individual machine instruction.a micro instruction specifies one or more micro oprations for the system.
How many machine cycles in the XCHG instruction?
Summary − So this instruction XCHG requires 1-Byte, 4-Machine Cycles (Opcode Fetch) and 4 T-States for execution as shown in the timing diagram.
Timing diagram of 8085?
Timing Diagram is a graphical representation. It represents the execution time taken by each instruction in a graphical format. The execution time is represented in T-states.Instruction Cycle:The time required to execute an instruction is called instruction cycle.Machine Cycle:The time required to access the memory or input/output devices is called machine cycle.T-State:The machine cycle and instruction cycle takes multiple clock periods.A portion of an operation carried out in one system clock period is called as T-state.MACHINE CYCLES OF 8085:The 8085 microprocessor has 5 (seven) basic machine cycles. They areOpcode fetch cycle (4T)Memory read cycle (3 T)Memory write cycle (3 T)I/O read cycle (3 T)I/O write cycle (3 T)Each instruction of the 8085 processor consists of one to five machine cycles, i.e., when the 8085 processor executes an instruction, it will execute some of the machine cycles in a specific order.The processor takes a definite time to execute the machine cycles. The time taken by the processor to execute a machine cycle is expressed in T-states.One T-state is equal to the time period of the internal clock signal of the processor.The T-state starts at the falling edge of a clock.
What is the Difference between machine op and pseudo op?
A pseudo-op is an assembly language instruction that specifies an operation of the assembler i.e about the base register & its contents e.g. USING instruction. On the other hand, a machine-op instruction. That represents a machine instruction to the assembler e.g. BR instruction is a machine-op instruction
What is sequential logic?
Any circuit that converts binary information into machine readiable form is called sequential circuit
How many machine cycles are required for RET instruction in 8085 microprocessor is?
RET instruction needs 3 machine cycles. One to fetch and decode the instruction(4 T states), and two more machine cycles(i.e. 2*3=6 T states) to read two bytes from the stack(stack is exterior to microprocessor, stack is in R/W memory, so to exchange data with stack needs machine cycles). Thus, RET instruction needs total 3 machine cycles and 10 T-states.
How 8085 timing diagram works based on each instruction?
Each instruction requires specific time for the execution of instruction and this time is called instruction cycle. Each instruction cycle consists 1 to 5 machine cycle -- opcode fetch, memory read, memory write, IO read, IO write and each machine cycle consist 3 to 6 T - states. Time required to execute 1 T-state = 1/ operating frequency of 8085 Microprocessor for example operating frequency = 2MHz then time required to execute 1 T-state = 0.5 uSec example: Calculate time required to execute instruction MOV C, A sol: This instruction has one machine cycle i.e. opcode fetch (In any instruction 1st cycle is always opcode fetch and opcode fetch consists 4 to 6 T state depend on the operation of particular instruction) so to execute MOV C, A required 4T states so time required to execute this instruction is 4*0.5usec = 2usec any other queries pls contect: nileshbahadure2000@yahoo.co.in example:Calculate the time required to execute LXI H,2000H sol:Here we have to draw opcode fetch and two memory reads as two bytes 00H and 20H have to be read from memory. i.e, opcode fetch+Memory reads *2(bytes address) =4+3+3 so to execute LXI H,2000H,the required T-states is 10T and time is 10*0.5usec=5usec
What is the difference between instruction cycle and machine cycle?
an instruction cycle may consist of a number of machine cycles.
How do you add new machine language instruction to a processor intsruction set?
To add a new machine language instruction to an processor instruction set, you need to replace the microcode of the processor.
