Replace shiftOut(), also fixing a possible bug.

The current shiftOut() is borrowed from Arduino, and is in an LGPL
file. Replace that file with a new MIT-licensed version containing a
new implementation.

The new version brings the clock line LOW before starting, to make
sure that the first pulse is detected if the clock line was previously
HIGH.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

1 files changed, 28 insertions, 31 deletions

diff --git a/wirish/wirish_shift.cpp b/wirish/wirish_shift.cpp
index 0f24f59..a032d50 100644
--- a/wirish/wirish_shift.cpp
+++ b/wirish/wirish_shift.cpp
@@ -1,40 +1,37 @@
-/*
- * wiring_shift.c - shiftOut() function
- * Part of Arduino - http://www.arduino.cc/
+/******************************************************************************
+ * The MIT License
  *
- * Copyright (c) 2005-2006 David A. Mellis
+ * Copyright (c) 2012 LeafLabs, LLC.
  *
- * 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.
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
  *
- * 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.
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
  *
- * 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 $
- */
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *****************************************************************************/
 
 #include <wirish/wirish.h>
 
-void shiftOut(uint8 dataPin, uint8 clockPin, uint8 bitOrder, uint8 val) {
-    int 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);
+void shiftOut(uint8 dataPin, uint8 clockPin, uint8 bitOrder, uint8 value) {
+    digitalWrite(clockPin, LOW);
+    for (int i = 0; i < 8; i++) {
+        int bit = bitOrder == LSBFIRST ? i : (7 - i);
+        digitalWrite(dataPin, (value >> bit) & 0x1);
+        togglePin(clockPin);
+        togglePin(clockPin);
     }
 }