呼吸灯

呼吸灯1s内由点亮到熄灭，下一秒由熄灭到点亮

image-20230322113259775

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module breath_led
#(
    parameter   CNT_1US_MAX=6'd49,
    parameter   CNT_1MS_MAX=10'd999,
    parameter   CNT_1S_MAX=10'd999
)
(
    input   wire    sys_clk     ,
    input   wire    sys_rst_n   ,
    output  reg    led_out
    );
reg     [9:0]     cnt_1s  ;
reg     [9:0]     cnt_1ms ;
reg     [5:0]     cnt_1us ;
reg               cnt_en  ;//使能信号，使每过1s，led_out信号取反    
//us信号   
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;
//ms信号   
always@(posedge sys_clk or  negedge sys_rst_n)
    if(sys_rst_n == 1'b0)
        cnt_1ms <= 10'd0;
    else if((cnt_1ms==CNT_1MS_MAX)&&(cnt_1us==CNT_1US_MAX))
        cnt_1ms <= 10'd0;
    else if(cnt_1us==CNT_1US_MAX)
        cnt_1ms <= cnt_1ms + 10'd1;
    else
        cnt_1ms <= cnt_1ms;
//s信号   
always@(posedge sys_clk or  negedge sys_rst_n)
    if(sys_rst_n == 1'b0)
        cnt_1s <= 6'd0;
    else if((cnt_1s==CNT_1S_MAX)&&(cnt_1ms==CNT_1MS_MAX)&&(cnt_1us==CNT_1US_MAX))
        cnt_1s <= 10'd0;
    else if((cnt_1ms==CNT_1MS_MAX)&&(cnt_1us==CNT_1US_MAX))
        cnt_1s <= cnt_1s +10'd1;
    else 
        cnt_1s <= cnt_1s;
//cnt_en信号   使能信号，使每过1s，led_out信号取反
always@(posedge sys_clk or  negedge sys_rst_n)
    if(sys_rst_n == 1'b0)
        cnt_en <= 1'b0;
    else if((cnt_1s==CNT_1S_MAX)&&(cnt_1ms==CNT_1MS_MAX)&&(cnt_1us==CNT_1US_MAX))
        cnt_en <= ~cnt_en;
    else
        cnt_en <= cnt_en;
//输出信号
always@(posedge sys_clk or  negedge sys_rst_n)
    if(sys_rst_n == 1'b0)
        led_out <= 1'b1;
    else if(((cnt_en==1'b0)&&(cnt_1ms<=cnt_1s))
            ||((cnt_en==1'b1)&&(cnt_1ms>cnt_1s)))
        led_out <= 1'b0;
    else
        led_out <= 1'b1; 
endmodule