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What is Movx instruction?

What is Movx instruction?

The MOVX instruction transfers data between the accumulator and external data memory. External memory may be addressed via 16-bits in the DPTR register or via 8-bits in the R0 or R1 registers. When using 8-bit addressing, Port 2 must contain the high-order byte of the address.

What is the purpose of using Movx and Movc instructions of 8051?

The MOVX Instruction This instruction is used to transfer data between external RAM and internal register A. The MOVC Instruction The letter C is added to the MOV to highlight the use of the opcode for moving data from the source address in the Code ROM to the A register in the 8051.

What is the operation of following instruction in 8051 microcontroller Movx a @RI?

MOVX A, @Ri This instruction will copy the data from 8 bit address pointed by register Ri of the selected register bank to the accumulator. MOVX A, @DPTR This instruction will copy the contents of external data memory location, pointed by DPTR to the accumulator.

What is the use of DPTR in 8051?

The Data Pointer DPTR is meant for pointing to data. It is used by the 8051 to access external memory using the address indicated by DPTR. DPTR is the only 16-bit register available and is often used to store 2-byte values.

What is DPH and DPL in 8051?

In 8051 assembly code, this address pointer is called DPTR. Because the 8051 is an 8-bit microcontroller, the 16-bit data pointer is controlled by two byte-wide registers, DPH (data pointer high-byte) and DPL (data pointer low-byte).

What is DJNZ in microcontroller?

Home » Instructions » DJNZ. The DJNZ instruction decrements the byte indicated by the first operand and, if the resulting value is not zero, branches to the address specified in the second operand.

What is AJMP?

Home » Instructions » AJMP. The AJMP instruction transfers program execution to the specified address. The address is formed by combining the 5 high-order bits of the address of the following instruction (for A15-A11), the 3 high-order bits of the opcode (for A10-A8), and the second byte of the instruction (for A7-A0).

What do the mnemonics DJNZ and Acall stand for?

JNZ – Jump if Accumulator Not Zero. JZ – Jump if Accumulator Zero. LCALL – Long Call. LJMP – Long Jump.

What is Jump Range 8051?

The relative address ranges from 00H to FFH which is divided into forward and backward jumps; that is, within –128 to +127 bytes of memory relative to the address of the current PC (program counter).

What is the function of TF0 bit in TCON register?

TF0: The TF0 stands for ‘timer0’ flag-bit. Whenever calculating the time delay in timer1, the TH0 and TL0 reaches to a maximum value that is ‘FFFF’, automatically. Whenever the TF0=1, then clear the flag bit and stop the timer.

What does DPTR stand for?


Acronym Definition
DPTR Division of Pediatric Translational Research and Treatment Development (US National Institute of Mental Health)
DPTR Diplomatic Pouch Tournament Ratings
DPTR Dynamic Progressive Transmission of Resolution
DPTR Delta Petroleum Target price

What is DPH in microcontroller?

What is the purpose of the MOVX instruction?

Description: MOVX moves a byte to or from External Memory into or from the Accumulator. If operand1 is @DPTR, the Accumulator is moved to the 16-bit External Memory address indicated by DPTR. This instruction uses both P0 (port 0) and P2 (port 2) to output the 16-bit address and data.

What is the difference between MOVC and MOVX?

Note: The MOVC instruction is used instead of the MOV instruction to access data in the code space/program memory. The MOVX command gets data from an externally connected ROM which might be used to increase the program memory. MOVC can only retrieve data from the program memory.

What does MOV mean in microcontrollers?

The MOV keyword is the opcode which tells the microcontroller to move data. ‘A’ keyword tells the microcontroller to store the data in the accumulator (the destination). ‘#’ directs the microcontroller to store immediate data (50H) in the accumulator (the source).

What are the parts of an 8051 microcontroller?

Any instruction in the 8051 microcontroller has two parts, an opcode, and an operand. The opcode tells the microcontroller what to do, whereas the operand holds the data on which the operation is to be performed. Let’s take a look at the first instruction.