AnalogWrite()

void analogWrite (uint8_t pin, int value)    

寫模擬引腳
參數(shù):

• pin 引腳編號(hào)
• value 0到255之間的值, 0對(duì)應(yīng)off, 255對(duì)應(yīng)on

寫一個(gè)模擬值(PWM)到引腳. 可以用來(lái)控制LED的亮度, 或者控制電機(jī)的轉(zhuǎn)速. 在執(zhí)行該操作后, 應(yīng)該等待一定時(shí)間后才能對(duì)該引腳進(jìn)行下一次的讀或?qū)懖僮? PWM的頻率大約為490Hz.

在一些基于ATmega168的新的Arduino控制板(如Mini 和BT)中, 該函數(shù)支持以下引腳: 3, 5, 6, 9, 10, 11. 在基于ATmega8的型號(hào)中支持9, 10, 11引腳.

例子:

int ledPin = 9;      // LED connected to digital pin 9
int analogPin = 3;   // potentiometer connected to analog pin 3
int val = 0;         // variable to store the read value

void setup()
{
  pinMode(ledPin, OUTPUT);   // sets the pin as output
}

void loop()
{
  val = analogRead(analogPin);   // read the input pin
  analogWrite(ledPin, val / 4);  // analogRead values go from 0 to 1023, analogWrite values from 0 to 255
}