arduino ibox项目实战22－AnalogWriteMega实验

armeasy

硬件平台：PC机一台，ibox卡片电脑一只，arduino扩展板一个，LED灯三个

软件平台：WIN7操作系统，android4.0或android4.4系统

实验目标：通过PWM0，PWM1，PWM2同时实现三盏灯的渐变效果。

打开arduino的IDE开发工具，依次点击文件->示例-> 03.Analog->AnalogWriteMega，AnalogWriteMega的示例程序将会被打开，其源码如下：

1. const int lowestPin = PWM0;
   
2. const int highestPin = PWM2;
   
3. 
   
4. void setup() {
   
5.   // set pins PWM0 through PWM2 as outputs:
   
6.   for (int thisPin = lowestPin; thisPin <= highestPin; thisPin++) {
   
7.     pinMode(thisPin, OUTPUT);
   
8.   }
   
9. }
   
10. 
    
11. void loop() {
    
12.   // iterate over the pins:
    
13.   for (int thisPin = lowestPin; thisPin <= highestPin; thisPin++) {
    
14.     // fade the LED on thisPin from off to brightest:
    
15.     for (int brightness = 0; brightness < 255; brightness++) {
    
16.       analogWrite(thisPin, brightness);
    
17.       delay(2);
    
18.     }
    
19.     // fade the LED on thisPin from brithstest to off:
    
20.     for (int brightness = 255; brightness >= 0; brightness--) {
    
21.       analogWrite(thisPin, brightness);
    
22.       delay(2);
    
23.     }
    
24.     // pause between LEDs:
    
25.     delay(100);
    
26.   }
    
27. }

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       运行程序，通过调节程序中相关参数，实现PWM脉宽变化，最终控制三盏灯的LED渐变效果。