muele-marlin/Marlin/src/gcode/control/M226.cpp

/**
 * Marlin 3D Printer Firmware
 * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
 * Based on Sprinter and grbl.
 * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
 *
 * 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 <http://www.gnu.org/licenses/>.
 *
 */

#include "../gcode.h"
#include "../../Marlin.h" // for pin_is_protected and idle()
#include "../../module/stepper.h"

/**
 * M226: Wait until the specified pin reaches the state required (M226 P<pin> S<state>)
 */
void GcodeSuite::M226() {
  if (parser.seen('P')) {
    const int pin_number = parser.value_int(),
              pin_state = parser.intval('S', -1); // required pin state - default is inverted

    if (WITHIN(pin_state, -1, 1) && pin_number > -1 && !pin_is_protected(pin_number)) {

      int target = LOW;

      stepper.synchronize();

      pinMode(pin_number, INPUT);
      switch (pin_state) {
        case 1:
          target = HIGH;
          break;
        case 0:
          target = LOW;
          break;
        case -1:
          target = !digitalRead(pin_number);
          break;
      }

      while (digitalRead(pin_number) != target) idle();

    } // pin_state -1 0 1 && pin_number > -1
  } // parser.seen('P')
}