Department Of Electronics

8051 Instruction Set ARITHMETIC OPERATIONS Mnemonic                           Description ADD A,Rn                         Add register to Accumulator   ADD A,direct                Add direct byte to Accumulator   ADD A,@Ri                   Add indirect RAM to Accumulator   ADD A,#data                 Add immediate data to Accumulator   ADDC A,Rn                   Add register to Accumulator with Carry ADDC A,direct              Add direct byte to Accumulator with Carry   ADDC A,@Ri                Add indirect RAM to Accumulator with Carry   ADDC A,#data             Add immediate data to Acc with Carry SUBB A,Rn                      Subtract Register from Acc with borrow SUBB A,direct                Subtract direct byte from Acc with borrow SUBB A,@Ri                    Subtract indirect RAM from ACC with borrow   SUBB A,#data                 Subtract immediate data from Acc with borrow   INC A                              Increment Accumulator   INC

** Explain 8051 instruction set (or) classification of 8051 instruction set (or) types of instructions.             Depending on operation   all instructions are divided in fivel groups: ·          Data Transfer Instructions ·          Arithmetic Instructions ·          Logic Instructions ·          Branch Instructions ·          Bit-oriented Instructions (or) Boolean instructions. Data   Transfer instructions :                      In 8051 microcontroller MOV,MOVC,MOVX,PUSH,POP,XCH and XCHD instructions are used to transfer data between registers and memory locations.           In 8051 microcontroller data transfer operations are : —>     Copy the content of a SFR to internal memory ( or) vice versa —>     Load an immediate operand to SFR/internal memory. —>     Exchange the content of SFR/internal memory with A. —>     Copy the content of program memory to Accumulator. —>      Copy the content of data memory to accumulator