8051 addressing
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This document discusses the different addressing modes of the 8051 microcontroller. It describes five addressing modes: immediate, direct, register direct, register indirect, and indexed. The immediate addressing mode transfers an 8-bit data directly to the accumulator. The direct addressing mode specifies the address of the source data instead of an immediate value. The register direct mode uses a register name as the source operand. The register indirect mode uses the value in a register as the address of the source data. Finally, the indexed addressing mode adds the value of a register like the data pointer or program counter to the accumulator to use as the address.
8051 addressing
- 1. ADDRESSING MODES OF 8051 by -SHARIQUE MULLA 13/3/2015 SHARIQUE MULLA
- 2. WHAT IS AN ADDRESSING MODE? • An Addressing mode is a way to address an operand. • Operand means the data we are operating upon (in most cases source data). • It can be a direct address of memory, it can be any numerical data, etc. 23/3/2015 SHARIQUE MULLA
- 3. ADDRESSING MODES 1. Immediate addressing mode 2. Direct addressing mode 3. Register direct addressing mode 4. Register indirect addressing mode 5. Indexed addressing mode 33/3/2015 SHARIQUE MULLA
- 4. 1) IMMEDIATE ADDRESSING MODE • This type of addressing mode is named as “immediate addressing”, because it transfers an 8-bit data immediately to the accumulator (destination register). • This instruction has an 8-bit immediate data at the operand. 43/3/2015 SHARIQUE MULLA
- 5. • Example- MOV A,#6AH 53/3/2015 SHARIQUE MULLA
- 6. 2) DIRECT ADDRESSING MODE • This is an another way of addressing an operand. • In this type of addressing mode, the address of the data (source data) is given as operand instead of immediate data . 63/3/2015 SHARIQUE MULLA
- 7. • Example- MOV A,04H 73/3/2015 SHARIQUE MULLA
- 8. 3) REGISTER DIRECT ADDRESSING MODE • In this type of addressing mode, we use the register name directly as source operand. • In 8051,there are 4 register banks, containing 8 registers (R0-R7) each. • Hence, the selection of a register bank is done by a special function register (SFR) called Processor Status Word (PSW). 83/3/2015 SHARIQUE MULLA
- 9. • Example- MOV A,R4 93/3/2015 SHARIQUE MULLA
- 10. 4) REGISTER INDIRECT ADDRESSING MODE • In this type of addressing mode, the address of the data (source data) is given in the register operand. • Here also, the register bank is required to be selected by PSW (Processor Status Word). • Here, the selected register is first loaded with a value which acts as the address of the data. 103/3/2015 SHARIQUE MULLA
- 11. • Example- MOV A,@R0 113/3/2015 SHARIQUE MULLA
- 12. 5) INDEXED ADDRESSING MODE • In this type of addressing, DPTR (Data Pointer) or PC (Program Counter), i.e. 16-bit registers, are used in the instruction. • Here, the content of DPTR or PC is added to the current content of accumulator. • The result acts as the address of the source data. • After execution the source data is stored in accumulator. 123/3/2015 SHARIQUE MULLA
- 13. • Example- MOV A,@A+DPTR 133/3/2015 SHARIQUE MULLA
- 14. PROCESSOR STATUS WORD (PSW) 143/3/2015 SHARIQUE MULLA
- 15. THANK YOU 153/3/2015 SHARIQUE MULLA