我只是在看一些示例代碼,遇到了一條線,我不完全明白爲什麼它需要完成。我明白你正在接受模擬值。顯然這個值在0到1024之間?爲什麼是這樣?爲什麼輸出需要在0到255之間映射?什麼決定了這裏使用的論點?有問題的行:Arduino map()方法 - 爲什麼?
// map it to the range of the analog out:
outputValue = map(sensorValue, 0, 1024, 0, 255);
在代碼中突出顯示:
created 29 Dec. 2008
Modified 4 Sep 2010
by Tom Igoe
This example code is in the public domain.
*/
// These constants won't change. They're used to give names
// to the pins used:
const int analogInPin = A0; // Analog input pin that the potentiometer is attached to
const int analogOutPin = 9; // Analog output pin that the LED is attached to
int sensorValue = 0; // value read from the pot
int outputValue = 0; // value output to the PWM (analog out)
void setup() {
// initialize serial communications at 9600 bps:
Serial.begin(9600);
}
void loop() {
// read the analog in value:
sensorValue = analogRead(analogInPin);
**// map it to the range of the analog out:
outputValue = map(sensorValue, 0, 1024, 0, 255);**
// change the analog out value:
analogWrite(analogOutPin, outputValue);
// print the results to the serial monitor:
Serial.print("sensor = ");
Serial.print(sensorValue);
Serial.print("\t output = ");
Serial.println(outputValue);
// wait 10 milliseconds before the next loop
// for the analog-to-digital converter to settle
// after the last reading:
delay(10);
}
非常感謝您的答覆。
有人可能會爭辯說,除以4的整數除此之外也會起作用,但map()也可以正常工作。 – Mchl
在抓握的手上,可以右移整數2. –
如果輸出必須介於0-255之間,analogInput爲0-1024,爲什麼? –