diff options
| author | Donald Delmar Davis <don@suspectdevices.com> | 2013-10-26 15:50:16 -0700 |
|---|---|---|
| committer | Donald Delmar Davis <don@suspectdevices.com> | 2013-10-26 15:50:16 -0700 |
| commit | 5bac9dcb4569f107315768677e4c6d580a743171 (patch) | |
| tree | 2822f877b07b7f6fbfeec54e40448b65ae196c15 /wiring_shift.c | |
| parent | 7edfa511b95c70673b87b988a0cd81eb2f8b168b (diff) | |
Diffstat (limited to 'wiring_shift.c')
| -rw-r--r-- | wiring_shift.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/wiring_shift.c b/wiring_shift.c new file mode 100644 index 0000000..cfe7867 --- /dev/null +++ b/wiring_shift.c @@ -0,0 +1,55 @@ +/* + 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); + } +} |
