cnt_vlog.v

Xilinx Ise 官方源代码盘 第四章

module cnt_vlog(CLK,RESET,CE,LOAD,DIR,DIN,COUNT);

   
 
// 4-bit synchronous up-down counter with count enable, 
// asynchronous reset and synchronous load
    input CLK;
    input RESET;
    input CE, LOAD, DIR;
    input [15:0] DIN;
    output [15:0] COUNT;
    reg [15:0] COUNT;
 
always @(posedge CLK or posedge RESET)
begin
   if (RESET)
      COUNT <= 16'b0;
   else begin
      if (LOAD)
         COUNT <= DIN;
      else
         if (CE)
            if (DIR)
               COUNT <= COUNT + 1;
            else
               COUNT <= COUNT - 1;
  end
end
 


endmodule