练习三 条件语句实现计数分频

模块源代码

`timescale 1ns / 1ps
//
// Company: 
// Engineer: 
// 
// Create Date:    14:50:03 07/25/2019 
// Design Name: 
// Module Name:    fdivision_test 
// Project Name: 
// Target Devices: 
// Tool versions: 
// Description: 10M分频到500K
//
// Dependencies: 
//
// Revision: 
// Revision 0.01 - File Created
// Additional Comments: 
//
//
module fdivision_test(
							RESET,
							F10M,
							F500K
    );
	input F10M,RESET;
	output F500K;
	reg F500K;
	reg [7:0]j;
	always @(posedge F10M)
		if(!RESET)
			begin
				F500K <= 0;
				j <= 0;
			end
		else 
			begin
				if(j == 19)
					begin
						j <= 0;
						F500K = ~F500K;
					end
				else 
					j <= j+1;
			end

endmodule

测试模块代码

`timescale 1ns / 100ps
`define clk_cycle 50

// Company: 
// Engineer:
//
// Create Date:   14:58:48 07/25/2019
// Design Name:   fdivision_test
// Module Name:   D:/FPGA/project/fdivision_test/vtf_fdivision_test.v
// Project Name:  fdivision_test
// Target Device:  
// Tool versions:  
// Description: 
//
// Verilog Test Fixture created by ISE for module: fdivision_test
//
// Dependencies:
// 
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
// 


module vtf_fdivision_test;

	// Inputs
	reg RESET;
	reg F10M;

	// Outputs
	wire F500K;

	// Instantiate the Unit Under Test (UUT)
	fdivision_test uut (
		.RESET(RESET), 
		.F10M(F10M), 
		.F500K(F500K)
	);

	always #`clk_cycle	F10M = ~F10M;
	
	initial begin
		// Initialize Inputs
		RESET = 1;
		F10M = 0;
		#100 RESET = 0;
		#100 RESET = 1;
		#10000 $stop;
		
	end
      
endmodule

仿真波形