Last-modified: 2016-04-09 (土) 05:11:38
Raspberry Pi/Lチカ

概要 †

Raspberry Pi2とC++でLチカを試します。
GPIOのアクセスにはWiringPiを使います。

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配線 †

000021.png
000001.jpg
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手順 †

  1. WiringPiのインストール
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    git clone git://git.drogon.net/wiringPi
cd wiringPi
git pull origin
./build
  2. vi led.cpp
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    #include <iostream>
#include <stdexcept>
#include <thread>
#include <wiringPi.h>
 
using namespace std;
 
namespace
{
    constexpr int OutPin = 25;
    constexpr int WaitMicroSec = 500 * 1000;
 
    /**
	 * @brief 信号の状態
	 */
    enum class State : int
    {
        Low = 0,
        High = 1
    };
};
 
/**
 * @brief LEDを0.5秒ごとにオン/オフ
 * 
 * @return 常に0
 */
int main()
{
    try
    {
        if (wiringPiSetupGpio() == -1)
        {
            throw runtime_error("Failed to wiringPiSetupGpio");
        }
        pinMode(OutPin, OUTPUT);
 
        for (;;)
        {
            digitalWrite(OutPin, static_cast<int>(State::High));
            this_thread::sleep_for(chrono::microseconds(WaitMicroSec));
            digitalWrite(OutPin, static_cast<int>(State::Low));
            this_thread::sleep_for(chrono::microseconds(WaitMicroSec));
        }
    }
    catch (exception& e)
    {
        cerr << e.what() << "\n";
    }
    catch (...)
    {
        cerr << "Unknown exception!\n";
    }
    return 0;
}
  3. vi Makefile
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    app: app.cpp
    g++ app.cpp -O2 -Wall -Wextra -std=gnu++11 -lwiringPi -oapp
clean:
    rm -f *.o app
  4. ビルド/実行
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    make
sudo ./app
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pythonなら †

  1. vi app.py
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    # coding:utf-8
 
# GPIO25 - 抵抗 - LED - GND
# LEDを0.5秒ごとにオン/オフする
 
import RPi.GPIO as GPIO
from time import sleep
 
# 初期化
GPIO.setmode(GPIO.BCM)
GPIO.setup(25, GPIO.OUT)
 
while True:
    GPIO.output(25, GPIO.HIGH)
    sleep(0.5)
    GPIO.output(25, GPIO.LOW)
    sleep(0.5)
  2. 実行
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    sudo python app.py
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検証時の環境 †