| 1 | /* |
| 2 | wiring_shift.c - shiftOut() function |
| 3 | Part of Arduino - http://www.arduino.cc/ |
| 4 | |
| 5 | Copyright (c) 2005-2006 David A. Mellis |
| 6 | |
| 7 | This library is free software; you can redistribute it and/or |
| 8 | modify it under the terms of the GNU Lesser General Public |
| 9 | License as published by the Free Software Foundation; either |
| 10 | version 2.1 of the License, or (at your option) any later version. |
| 11 | |
| 12 | This library is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | Lesser General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU Lesser General |
| 18 | Public License along with this library; if not, write to the |
| 19 | Free Software Foundation, Inc., 59 Temple Place, Suite 330, |
| 20 | Boston, MA 02111-1307 USA |
| 21 | */ |
| 22 |
|
| 23 | #include "wiring_private.h" |
| 24 |
|
| 25 | uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder) { |
| 26 | uint8_t value = 0; |
| 27 | uint8_t i; |
| 28 |
|
| 29 | for (i = 0; i < 8; ++i) { |
| 30 | digitalWrite(clockPin, HIGH); |
| 31 | if (bitOrder == LSBFIRST) |
| 32 | value |= digitalRead(dataPin) << i; |
| 33 | else |
| 34 | value |= digitalRead(dataPin) << (7 - i); |
| 35 | digitalWrite(clockPin, LOW); |
| 36 | } |
| 37 | return value; |
| 38 | } |
| 39 |
|
| 40 | void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val) |
| 41 | { |
| 42 | uint8_t i; |
| 43 |
|
| 44 | for (i = 0; i < 8; i++) { |
| 45 | if (bitOrder == LSBFIRST) |
| 46 | digitalWrite(dataPin, !!(val & (1 << i))); |
| 47 | else |
| 48 | digitalWrite(dataPin, !!(val & (1 << (7 - i)))); |
| 49 | |
| 50 | digitalWrite(clockPin, HIGH); |
| 51 | digitalWrite(clockPin, LOW); |
| 52 | } |
| 53 | } |
| 54 |
|
Index