Arduino的如何检测LED的状态呢？ [英] How can Arduino detect the state of an LED?

问题描述

我工作了Arduino的闪烁/褪色灯程序。我试图建立的是基于LED的状态和某些开关组合一些交互。试想一下：当一个按钮为pressed，如果一个LED指示灯亮我想将其关闭，如果一个LED指示灯灭我想打开它

I'm working on a blinking/fading lights program for Arduino. I'm trying to build in some interactivity that's based on LED state and certain switch combinations. Consider: When a button is pressed, if an LED is ON I want to turn it off and if an LED is OFF I want to turn it on.

不过，我没能找到有关确定LED状态的任何信息。最接近的是这个问题关于Android，但我想，如果我找到了可以从Arduino的平台做到这一点。有没有人有任何实际经验或建议吗？

However, I've not been able to find any information about determining LED state. The closest was this question about Android, but I'm trying to find out if I can do this from the Arduino platform. Does anyone have any practical experience or advice?

推荐答案

您有几种选择：

一，可以将LED状态保存在一个布尔值，并在按钮preSS，否定的，并将其写入到LED端口：

One, you can store the LED state in a boolean, and on button press, negate that and write it to the LED port:

void loop()
{
    static int ledState = 0; // off
    while (digitalRead(BUTTON_PIN) == 0)
        ; // wait for button press

    ledState = !ledState;
    digitalWrite(LED_PORT, ledState);
}

二，如果你不介意直接访问AVR的端口：

Two, if you don't mind accessing the ports of the AVR directly:

void init()
{
    DDRD = 0x01; // for example: LED on port B pin 0, button on port B pin 1
    PORTB = 0x00;
}

void loop()
{
    while (PINB & 0x02 == 0)
        ; // loop until the button is pressed

    PORTB ^= 0x01; // flip the bit where the LED is connected
}

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