Microprocessors and Microcontrollers: Unit III: (a) 8051 Microcontroller
Stack and Stack Pointer
8051 Microcontroller
Review Questions : 1. Explain the operation of stack in 8051. 2. Define SP.
Stack and Stack Pointer
The
stack refers to an area of internal RAM that is used to store and retrieve data
quickly. The stack pointer register is used by the 8051 to hold an internal RAM
address that is called top of stack. The stack pointer register is 8-bit wide.
It is increased before data is stored during PUSH and CALL instructions and
decremented after data is restored during POP and RET instructions.
The
stack array can reside anywhere in on-chip RAM. The stack pointer is
initialized to 07H after a reset. This causes the stack to begin at location
08H. The operation of stack and stack pointer is illustrated in Fig. 14.7.1.
The
stack may overwrite data in the register banks, bit-addressable RAM and
scratch-pad RAM. Thus to avoid conflict with the register, bit-addressable RAM
and scratch-pad RAM data, the stack is initialized at a higher location in the
internal RAM.
Review Questions
1. Explain the
operation of stack in 8051.
2. Define SP.
Microprocessors and Microcontrollers: Unit III: (a) 8051 Microcontroller : Tag: : 8051 Microcontroller - Stack and Stack Pointer