Stack and Stack Pointer - PIC18F Programming Model and Instruction Set

TL;DR

Microcontroller stack and stack pointers are used as storage spaces for return addresses of subroutines and temporary data or addresses. Stack pointers can be modified by the user to access and modify stack data directly.

Transcript

hello students today we'll see stack and stack pointer stack is we have already seen the stack in program memory the region is allocated in program memory but the stack is not part of program memory as well as data memory the microcontroller stack has only been used as a storage space for return address of subroutines or interpreting the stack is n... Read More

Key Insights

• 🏪 The stack in a microcontroller is separate from program and data memory, and is used for storing return addresses and temporary data.
• 🫷 Push and pop instructions are used to store and retrieve data from the stack.
• ♿ The user has access to the stack pointer and can modify it to directly access and modify stack data.
• 🫦 The stack pointer register has 5 bits for selecting one of 32 stack levels.
• ❓ The stack operates on a last-in, first-out principle.
• 🫷 The stack pointer is automatically incremented when data is pushed onto the stack and decremented when data is popped from the stack.
• ®️ Stack pointer register configuration is given in the special function registers.

Questions & Answers

Q: What is the purpose of the stack in a microcontroller?

The stack is used as a storage space for return addresses of subroutines and temporary data or addresses for the microcontroller's execution.

Q: How can data be stored and retrieved from the stack?

Data can be stored on the stack using the push instruction and retrieved using the pop instruction without disturbing the main program execution.

Q: Can the user modify the stack pointer and stack data directly?

Yes, the user has access to the stack pointer and can modify it to access and modify the stack data directly, as long as it is within the provided stack levels.

Q: How many stack levels are available in a microcontroller?

In the microcontroller discussed, there are 32 stack levels available, from stack level 1 to stack level 31.

Summary & Key Takeaways

• The stack in a microcontroller is used to store return addresses of subroutines and temporary data or addresses.

• Push and pop instructions are used to store and retrieve data from the stack without disturbing the main program execution.

• The microcontroller has 32 stack levels, with the stack pointer register being used to access different stack locations.