Special Function Registers Special function registers are dedicated memory locations accessible by the microprocessor. They are used to store data and instr...
Special Function Registers
Special function registers are dedicated memory locations accessible by the microprocessor. They are used to store data and instructions that have specific purposes and are not part of the basic memory (RAM).
Purpose:
Data storage: Special function registers are used to store data such as timers, counters, flags, and input/output (I/O) status.
Instruction storage: They store the instructions used by the microprocessor, including jump instructions and subroutine calls.
Memory protection: Special function registers can be used to implement memory protection mechanisms, ensuring that only authorized data can be accessed.
Examples:
Timer 0: Stores the timer counter value, which increments automatically.
Input Register: Holds the address of the next input byte to be read.
Output Register: Stores the data to be sent through the output port.
Status Register: Contains status information such as the processor's mode and flags.
Benefits:
Reduced memory overhead: By storing data and instructions in specialized registers, the microprocessor can save memory space.
Control of program flow: Special function registers allow the program to control the execution of instructions by setting up jump addresses.
Protection from errors: Memory protection mechanisms can prevent access to unauthorized data, reducing the risk of data corruption.
Note:
Special function registers are typically located in specific memory addresses within the microprocessor. The address of these registers is typically specified in the microprocessor's data sheet or instruction manual