Direct Addressing Mode
- This mode allows you to specify the operand by giving its actual memory address or by giving its abbreviated name.
- Direct addressing can access any on-chip variable or hardware register
- Used for accessing SFR
- SFR can be accessed by their name or by their address
- Operand address should be known at assemble-time
- The value to be stored in memory is obtained by directly retrieving it from another memory location
- In the 8051, only direct addressing mode is allowed for accessing the stack. Pushing R3 of bank 0 is coded as “PUSH 03″. “POP 04″ will pop the top of the stack into R4 of bank 0.
- Example: MOV A, P3
The above instruction transfer the content of P3 to accumulator
MOV A, 20H
The above instruction transfer the content of RAM location 20H to accumulator
Related topics:
8051 Addressing Modes | 8051 Register Addressing Mode | 8051 Indirect Addressing Mode | 8051 Immediate Addressing Mode | 8051 Relative Addressing Mode | 8051 Absolute Addressing Mode | 8051 Long Addressing Mode | 8051 Indexed Addressing Mode | 8051 External Addressing Mode
List of topics: 8051
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