饂飩コーディング

iOSアプリやら、Unityやら、Cocos2dやらごにょごにょ書いております

UNOをスリープさせてみる

まずは以下を一通り読んでみる。
playground.arduino.cc
Forumの中のPlayGroundにある記事なのだが以下の4点を把握できる。

1、スリープにもいくつかモードがありIDOLはカウンターを停止させないとすぐにスリープ解除されてしまう
2、外部割り込みのPINは決まっている(2Pinor3Pin)
3、スリープ前にLED等は消灯(電力消費停止)しておかないとスリープしてもLEDは点灯したまま
4、スリープの仕方も複数あるらしく古いやり方もあってWEB上には混在している。

具体的には上記記事のサンプルを使ってみましょう

#include <avr/sleep.h>
 
/* Sleep Demo Serial
 * -----------------
 * Example code to demonstrate the sleep functions in an Arduino.
 *
 * use a resistor between RX and pin2. By default RX is pulled up to 5V
 * therefore, we can use a sequence of Serial data forcing RX to 0, what
 * will make pin2 go LOW activating INT0 external interrupt, bringing
 * the MCU back to life
 *
 * there is also a time counter that will put the MCU to sleep after 10 secs
 *
 * NOTE: when coming back from POWER-DOWN mode, it takes a bit
 *       until the system is functional at 100%!! (typically <1sec)
 *
 * Copyright (C) 2006 MacSimski 2006-12-30
 * Copyright (C) 2007 D. Cuartielles 2007-07-08 - Mexico DF
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */
 
int wakePin = 2;                 // pin used for waking up
int sleepStatus = 0;             // variable to store a request for sleep
int count = 0;                   // counter
 
void wakeUpNow()        // here the interrupt is handled after wakeup
{
  // execute code here after wake-up before returning to the loop() function
  // timers and code using timers (serial.print and more...) will not work here.
  // we don't really need to execute any special functions here, since we
  // just want the thing to wake up
}
 
void setup()
{
  pinMode(wakePin, INPUT);
 
  Serial.begin(9600);
 
  /* Now it is time to enable an interrupt. In the function call
   * attachInterrupt(A, B, C)
   * A   can be either 0 or 1 for interrupts on pin 2 or 3.  
   *
   * B   Name of a function you want to execute while in interrupt A.
   *
   * C   Trigger mode of the interrupt pin. can be:
   *             LOW        a low level trigger
   *             CHANGE     a change in level trigger
   *             RISING     a rising edge of a level trigger
   *             FALLING    a falling edge of a level trigger
   *
   * In all but the IDLE sleep modes only LOW can be used.
   */
 
  attachInterrupt(0, wakeUpNow, LOW); // use interrupt 0 (pin 2) and run function
                                      // wakeUpNow when pin 2 gets LOW
}
 
void sleepNow()         // here we put the arduino to sleep
{
    /* Now is the time to set the sleep mode. In the Atmega8 datasheet
     * https://www.atmel.com/dyn/resources/prod_documents/doc2486.pdf on page 35
     * there is a list of sleep modes which explains which clocks and
     * wake up sources are available in which sleep mode.
     *
     * In the avr/sleep.h file, the call names of these sleep modes are to be found:
     *
     * The 5 different modes are:
     *     SLEEP_MODE_IDLE         -the least power savings
     *     SLEEP_MODE_ADC
     *     SLEEP_MODE_PWR_SAVE
     *     SLEEP_MODE_STANDBY
     *     SLEEP_MODE_PWR_DOWN     -the most power savings
     *
     * For now, we want as much power savings as possible, so we
     * choose the according
     * sleep mode: SLEEP_MODE_PWR_DOWN
     *
     */  
    set_sleep_mode(SLEEP_MODE_PWR_DOWN);   // sleep mode is set here
 
    sleep_enable();          // enables the sleep bit in the mcucr register
                             // so sleep is possible. just a safety pin
 
    /* Now it is time to enable an interrupt. We do it here so an
     * accidentally pushed interrupt button doesn't interrupt
     * our running program. if you want to be able to run
     * interrupt code besides the sleep function, place it in
     * setup() for example.
     *
     * In the function call attachInterrupt(A, B, C)
     * A   can be either 0 or 1 for interrupts on pin 2 or 3.  
     *
     * B   Name of a function you want to execute at interrupt for A.
     *
     * C   Trigger mode of the interrupt pin. can be:
     *             LOW        a low level triggers
     *             CHANGE     a change in level triggers
     *             RISING     a rising edge of a level triggers
     *             FALLING    a falling edge of a level triggers
     *
     * In all but the IDLE sleep modes only LOW can be used.
     */
 
    attachInterrupt(0,wakeUpNow, LOW); // use interrupt 0 (pin 2) and run function
                                       // wakeUpNow when pin 2 gets LOW
 
    sleep_mode();            // here the device is actually put to sleep!!
                             // THE PROGRAM CONTINUES FROM HERE AFTER WAKING UP
 
    sleep_disable();         // first thing after waking from sleep:
                             // disable sleep...
    detachInterrupt(0);      // disables interrupt 0 on pin 2 so the
                             // wakeUpNow code will not be executed
                             // during normal running time.
 
}
 
void loop()
{
  // display information about the counter
  Serial.print("Awake for ");
  Serial.print(count);
  Serial.println("sec");
  count++;
  delay(1000);                           // waits for a second
 
  // compute the serial input
  if (Serial.available()) {
    int val = Serial.read();
    if (val == 'S') {
      Serial.println("Serial: Entering Sleep mode");
      delay(100);     // this delay is needed, the sleep
                      //function will provoke a Serial error otherwise!!
      count = 0;
      sleepNow();     // sleep function called here
    }
    if (val == 'A') {
      Serial.println("Hola Caracola"); // classic dummy message
    }
  }
 
  // check if it should go to sleep because of time
  if (count >= 10) {
      Serial.println("Timer: Entering Sleep mode");
      delay(100);     // this delay is needed, the sleep
                      //function will provoke a Serial error otherwise!!
      count = 0;
      sleepNow();     // sleep function called here
  }
}