// Clock Generator for D40 ( 4 bit Simple Microprocessor ) // Functionality : System Clock Generation // Date : 97/12/10 (Wed) // Author : tootsuka@de.tokyo-ct.ac.jp module cg ( clk ); output clk ; // system clock pulses reg clk ; initial begin clk = 0 ; end always // 1 microsecond period clock geneation begin #500 clk = 1; #500 clk = 0; end endmodule // end of clock_geneartor (CG)