//以下程式如果要正常執行，需要加入按鍵去抖部分

always@( posedge clk )

begin

if( !rst )

begin

cnt

end

else

begin

case ( {button1,button2} )

2"b00:

begin

cnt

end

2"b10:

begin

if ( cnt == "hff )

begin

cnt

error

end

else

begin

cnt

end

end

2"b01:

begin

if ( cnt == "h00 )

begin

cnt

error

end

else

begin

cnt

end

end

2"b11:

begin

cnt

end

endcase

end

end