8051 direct addressing — does the instruction 'MOV 23H, A' copy the Accumulator to internal RAM address 23H? Decide whether this statement about direct-address destination is correct.

Introduction / Context:
Addressing modes determine where data moves in a single cycle. In the 8051, direct addressing targets a specific internal RAM or SFR address. Understanding what range maps to internal RAM vs SFRs prevents subtle bugs.

Given Data / Assumptions:

• Instruction: MOV 23H, A
• Address 23H is within 00H–7FH (lower internal RAM in a base 8051)
• Accumulator A contains a byte to store

Concept / Approach:
Direct destinations in the lower 128 bytes (00H–7FH) reference internal RAM. The bit-addressable area is 20H–2FH, but byte writes to 23H still write the full byte. SFRs occupy 80H–FFH, so 23H is not an SFR address on a basic 8051.

Step-by-Step Solution:

Verification / Alternative check:
Cross-reference the 8051 memory map: SFRs start at 80H; lower 128 is internal RAM, so the instruction is a valid byte move to RAM address 23H.

Why Other Options Are Wrong:

• False: contradicts the memory map.
• Writes to SFR 23H: SFRs are at 80H–FFH.
• Only bit transfer: MOV writes a full byte.
• Requires @R0/@R1: direct addressing does not require indirect registers.

Common Pitfalls:

• Confusing bit-addressable region with bit-only access; bytes are still writable.

Final Answer:
True