From the circuit diagram, it can be seen that the core of the VFS5 spindle module is the MCS-96 Series MCU or micro controller N80C196KB16(136) of Intel company, with a small amount of RAM in the chip, but without ROM, it usually needs external expansion. The module uses AM27C256(137) and DS1230Y-120(114) as external program and data storage, and the memory space is 32K, respectively. AM27C256 has no security byte, and programmers can read the code directly. The N80C196KB16 fetches code from the address 2080H after reset, It is easy to obtain the assembly language program by disassembling code from the address. Then the control flow chart can be drawn (see below).