What is the difference between the initial block and always blocks in SystemVerilog?

Difference between initial block and always blocks in SystemVerilog

The initial block and always blocks are important structures in SystemVerilog used for specifying the behavior of digital logic designs. Here are the key differences between the initial block and always blocks:

• Initial Block: The initial block is executed only once at the beginning of simulation when the simulation starts. It is used to initialize variables and register values. The initial block is a static block and does not repeat.
• Always Block: The always block is a dynamic block that continuously repeats based on its sensitivity list. It is used to model sequential and combinational logic. The always block triggers whenever the signal sensitivity list changes.

Therefore, while the initial block runs only once at the start of simulation, the always block runs continuously based on the sensitivity list, making it suitable for modeling sequential logic behavior in SystemVerilog.