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Why should the microcontroller program always start at ORG 0000H?
ORG(origin): This directive indicates the start of the program. This is used to set the register address during assembly. For example; ORG 0000h tells the compiler all subsequent code starting at address 0000h.
What is org in assembly language?
ORG means origin ORG is used for specific addressing in microprocessor and microcontroller programming. For example: .org 0000H. This means we want to start our program from the 0000H address.
What is DPTR in 8051?
The Data Pointer (DPTR) is the 8051’s only user-accessible 16-bit (2-byte) register. The Accumulator, R0–R7 registers and B register are 1-byte value registers. DPTR is meant for pointing to data. It is used by the 8051 to access external memory using the address indicated by DPTR.
Which of the following statements is false regarding an 8051?
Which of the following statements is FALSE regarding an 8051? The stack pointer in the 8051 is only eight bits wide. The storing of a CPU register in the stack is called a PUSH. As we push data onto the stack, the stack pointer is decremented by one.
What is ORG 0h in 8051?
The following are some more widely used directives of the 8051. ORG (origin) The ORG directive is used to indicate the beginning of the address. The number that comes after ORG can be either in hex or in decimal. If the number is not followed by H, it is decimal and the assembler will convert it to hex.
What does the instruction ORG 00h do?
org 00h is a directive that tells the assembler where to write the program into the micrcocontroller’s program memory. By using a data address of 00h, org tells MPLAB to store the first program instruction into the first memory location (address 0000h), which is also known as the Reset Vector.
What is the purpose of ORG directive is?
* ORG – The origin directive sets the location counter to the value specified. Subsequent statements are assigned memory locations starting with the new location counter value. The location counter is a counter in the assembler program that is used to assign storage addresses for the program.
What is the function of an org directive?
org directive advances the location counter in the current section to new-location.
What is the default interrupt priority in 8051?
8051 has an interrupt priority register to assign priority to interrupts. Bit 7,6,5 – Reserved bits. 1 = Assign a high priority to serial interrupt. 0 = Assign low priority to serial interrupt….Interrupt priority.
| Priority | Interrupt source | Intr. bit / flag |
|---|---|---|
| 5 | Serial interrupt | (TI/RI) |