Question

On power up, the 8051 uses which RAM locations for register R0–R7?

• A. 00–07
• B. 00–2F
• C. 00–7F
• D. 00–FF

Hint:

Default register bank = Bank 0 → addresses 00H–07H.

Answer 1

The Correct Option is A

Concept: 8051 has four register banks, each containing registers R0–R7.

Step 1: Default bank On reset, Bank 0 is selected.

Step 2: Address mapping Bank 0 occupies addresses: \[ 00H \text{ to } 07H \]

Step 3: Registers mapping \[ R0 \rightarrow 00H,\quad R7 \rightarrow 07H \]

Step 4: Other banks Other banks are located at higher addresses.

Step 5: Conclusion \[ \boxed{00\text{–}07} \]

Final Answer: \[ \boxed{(A)} \]