| /* |
| 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 "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); |
| } |
| } |