The Mikrocodesimulator is a Windows compatible application, on which microprocessor functionality can be simulated didactially. The user is able to investigate on various levels of abstraction how microcodes are understood as coded switch settings, how these codes are controlled executed in tacts, how microcodes are grouped in sequence to a microcode program placed in a ROM, and finally how a structured microcode program can interpret machine codes programmed in an external RAM for execution. In this manner, the operation range of single opating devices like ALU and memory composed to a programmable and versitile computer is perceptible and realizable. Whereas ALU, memory operation and the interaction are predefined, interaction control can be set as microcode commands in the ROM. By this, the user can design and implement his own designed machine codes into the ROM as OpCodes and is able to verify them step by step in single phases, tacts, and cycles. The utilisation of the application is remarkable intuitive. On the screen, the user enables the virtual devices belonging to the level of simulation. The content of the device interfaces can be modified by various editors easily in different numerative systems.