FPGA-Based Communication Module in Numerical Control System with Software Hardening Technology

In order to accomplish the software hardening technology (SHT) of the whole computer numerical control (CNC) system, it is necessary to harden the communication module based on field programmable gate array (FPGA). This paper puts forward the technical scheme of SHT for the serial communication module, which can set the transmission rate conveniently and enhance the stability and portability of communication process in the CNC machine tool. Verilog hardware description language (Verilog HDL) is adopted in Quartus II 9.0 development environment, based on FPGA chip of Altera company CYCLONE II series. The double buffer circuits of asynchronous reset and synchronous release are employed in the serial communication module to reduce the occurring probability of asynchronous reset metastable state. There are four different baud rates which can be set in the serial communication module. The simulation results demonstrate that the proposed scheme is reasonable and feasible.