count10.v

verilog设计的4位频率计

module count10(out,cout,en,clk,clr);
output[3:0] out;
output cout;
input en,clr,clk;
reg[3:0] out;
always @(posedge clk or posedge clr)
  begin
   
     
      if(clr) out<=0;
     
    
       else  if(en)   
        begin if(out==9)out<=0;
             else      out<=out+1;
        end 
      
  end
assign cout=((out==9)&en)?1:0;
endmodule