module breath_led
#(
parameter CNT_1S_MAX = 10'd999 ,
parameter CNT_1MS_MAX = 10'd999 ,
parameter CNT_1US_MAX = 6'd49
)
(
input wire sys_clk ,
input wire sys_rst_n ,
output reg led_out
);
reg [9:0] cnt_1s;
reg [9:0] cnt_1ms;//最大计数值999,十位宽
reg [5:0] cnt_1us;//最大计数值49 ,需要六位
reg cnt_en;
//1us计数器
always@(posedge sys_clk or negedge sys_rst_n)
if(sys_rst_n == 1'b0)
cnt_1us <= 6'd0;
else if(cnt_1us == CNT_1US_MAX)
cnt_1us <= 6'd0;
else
cnt_1us <= cnt_1us + 6'd1;
//1m