Q9Microprocessor and Microcontroller
Question
2 marks
What is the role of Instruction Register in 8085 microprocessor?
Answer
The Instruction Register securely holds the fetched opcode while the internal decoder mathematically translates it.
The Instruction Register (IR) is an incredibly critical, internal 8-bit holding register strictly invisible to the programmer. During the absolute first phase of the instruction cycle (the Fetch cycle), the 8-bit opcode fetched from main memory is securely deposited directly into the IR. It holds this binary command perfectly stable while the attached Instruction Decoder translates it into physical control signals.