It is a program controlled semi conductor device (IC), which fetches, decodes and execute instructions.
What are the basic units of microprocessor ?
The basic units or blocks of microprocessor are ALU, an array of registers and control unit.
What is a bus ?
Bus is a group of conducting lines that carries data, address and controlsignals.
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.
Why is Address bus unidirectional ?
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.
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.
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.
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.
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.
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.