text: /*
   wiring_shift.c - shiftOut() function
   Part of Arduino - http://www.arduino.cc/
   Copyright (c) 2005-2006 David A. Mellis
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.
   This library 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
   Lesser General Public License for more details.
   You should have received a copy of the GNU Lesser General
   Public License along with this library; if not, write to the
   Free Software Foundation, Inc., 59 Temple Place, Suite 330,
   Boston, MA  02111-1307  USA
   $Id: wiring.c 248 2007-02-03 15:36:30Z mellis $
   */
   
  #include "esp32-hal.h"
  #include "wiring_private.h"
  
  uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder) {
      uint8_t value = 0;
      uint8_t i;
  
      for(i = 0; i < 8; ++i) {
          digitalWrite(clockPin, HIGH);
          if(bitOrder == LSBFIRST)
              value |= digitalRead(dataPin) << i;
          else
              value |= digitalRead(dataPin) << (7 - i);
          digitalWrite(clockPin, LOW);
      }
      return value;
  }
  
  void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val) {
      uint8_t i;
  
      for(i = 0; i < 8; i++) {
          if(bitOrder == LSBFIRST)
              digitalWrite(dataPin, !!(val & (1 << i)));
          else
              digitalWrite(dataPin, !!(val & (1 << (7 - i))));
  
          digitalWrite(clockPin, HIGH);
          digitalWrite(clockPin, LOW);
      }
  }
  