PWM的LEDG灯控制

通过PWM控制LEDG灯的频率

 1 module pwm(
 2     clk,
 3     reset_n,
 4     high_dur,
 5     total_dur,
 6     pwm,
 7     toggle
 8 );
 9 
10  input                 clk;
11  input                reset_n;
12  input        [31:0]    high_dur;
13 input        [31:0]    total_dur;
14 output        pwm;
15 output    reg    toggle;
16 
17 reg    [31:0]    tick;
18 
19 always @ (posedge clk or negedge reset_n)
20 begin
21     if (!reset_n)
22     begin
23         tick <= 0;
24         toggle <= 0;
25     end
26     else if (tick >= total_dur)
27     begin
28         tick <= 0;
29         toggle <= ~toggle;
30     end
31     else
32         tick <= tick + 1;
33 end
34 
35 assign pwm = (tick < high_dur)?1'b1:1'b0;
36 
37 endmodule
38

 

可以通过 SW按钮来控制LED

  1 module DE0_PWM_LED(
  2         ////////////////////    Clock Input         ////////////////////     
  3         CLOCK_50,                        //    50 MHz
  4         ////////////////////////    LED        ////////////////////////
  5         LEDG,                            //    LED Green[9:0]        
  6         ////////////////////    DPDT Switch        ////////////////////
  7         SW,                                //    Toggle Switch[9:0]
  8         reset_n
  9 );
 10 
 11 ////////////////////////    Clock Input         ////////////////////////
 12 input            CLOCK_50;                //    50 MHz
 13 ////////////////////////////    LED        ////////////////////////////
 14 output    [9:0]    LEDG;                    //    LED Green[9:0]
 15 ////////////////////////    DPDT Switch        ////////////////////////
 16 input    [9:0]    SW;                        //    Toggle Switch[9:0]
 17 input reset_n;
 18 //=======================================================
 19 //  REG/WIRE declarations
 20 //=======================================================
 21 wire reset_n;
 22 //assign reset_n = 1'b1;
 23 wire [9:0] MAX_LIGHT;
 24 //`define MAX_LIGHT        8'hFF
 25 wire [11:0] MAX_LIGHT_TICK;
 26 //`define MAX_LIGHT_TICK    11'h7FF
 27 
 28 reg [8:0]    light;
 29 reg [9:0]    light_tick;
 30 reg            lighter;
 31 wire        toggle;
 32 
 33 
 34 //=======================================================
 35 //  Structural coding
 36 //=======================================================
 37 
 38 //
 39 always @ (posedge toggle or negedge reset_n)
 40 begin
 41     if (!reset_n)
 42     begin
 43         light_tick <= 0;
 44         light <= 0;
 45         lighter <= 1'b1;
 46     end
 47     else if (light_tick >= MAX_LIGHT_TICK)
 48     begin
 49         light_tick <= 0;
 50         if (lighter)
 51         begin
 52             if (light >= MAX_LIGHT)
 53                 lighter <= 1'b0;
 54             else
 55                 light <= light + 1'b1;
 56         end
 57         else
 58         begin
 59             if (light == 0)
 60                 lighter <= 1'b1;
 61             else
 62                 light <= light - 1'b1;        
 63         end
 64     end
 65     else
 66         light_tick <= light_tick + 1'b1;
 67 end
 68 
 69 wire led_pwm;
 70 wire [8:0]    linear_light;
 71 // linearlize process: input pwm->led illuminance (user can optimal linearity here)
 72 assign linear_light = (light < MAX_LIGHT/2)?light/4:(MAX_LIGHT/10+(light-MAX_LIGHT/2)*9/4);
 73 
 74 pwm pwm_inst(
 75     .clk(CLOCK_50),
 76     .reset_n(reset_n),
 77     .high_dur(linear_light),
 78     .total_dur(MAX_LIGHT),
 79     .pwm(led_pwm),
 80     .toggle(toggle)
 81 );
 82 
 83 assign LEDG[0] = led_pwm;
 84 assign LEDG[1] = led_pwm;
 85 assign LEDG[2] = led_pwm;
 86 assign LEDG[3] = led_pwm;
 87 assign LEDG[4] = led_pwm;
 88 assign LEDG[5] = led_pwm;
 89 assign LEDG[6] = led_pwm;
 90 assign LEDG[7] = led_pwm;
 91 assign LEDG[8] = led_pwm;
 92 assign LEDG[9] = led_pwm;
 93 
 94 
 95 assign MAX_LIGHT = SW;
 96 assign MAX_LIGHT_TICK = MAX_LIGHT<<1;
 97 
 98 endmodule
 99 
100 
101

 

 

posted on 2010-11-26 11:08  齐威王  阅读(1551)  评论(0)  编辑  收藏  举报

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