1 files changed, 133 insertions, 0 deletions
diff --git a/source/arduino/shiftout.rst b/source/arduino/shiftout.rst
new file mode 100644
index 0000000..2277cf1
--- /dev/null
+++ b/source/arduino/shiftout.rst
@@ -0,0 +1,133 @@
+.. _arduino-shiftout:
+
+shiftOut()
+==========
+
+Description
+-----------
+
+Shifts out a byte of data one bit at a time. Starts from either the
+most (i.e. the leftmost) or least (rightmost) significant bit. Each
+bit is written in turn to a data pin, after which a clock pin is
+pulsed to indicate that the bit is available.
+
+
+
+This is a software implementation; Arduino (as of 0019) also
+provides an `SPI library <http://arduino.cc/en/Reference/SPI>`_
+that uses the hardware implementation.
+
+
+
+Syntax
+------
+
+shiftOut(dataPin, clockPin, bitOrder, value)
+
+
+
+Parameters
+----------
+
+dataPin: the pin on which to output each bit (*int*)
+
+
+
+clockPin: the pin to toggle once the **dataPin** has been set to
+the correct value (*int*)
+
+
+
+bitOrder: which order to shift out the bits; either **MSBFIRST** or
+**LSBFIRST**.
+(Most Significant Bit First, or, Least Significant Bit First)
+
+
+
+value: the data to shift out. (*byte*)
+
+
+
+Returns
+-------
+
+None
+
+
+
+Note
+----
+
+The **dataPin** and **clockPin** must already be configured as
+outputs by a call to
+`pinMode <http://arduino.cc/en/Reference/PinMode>`_\ ().
+
+
+
+**shiftOut** is currently written to output 1 byte (8 bits) so it
+requires a two step operation to output values larger than 255.
+
+::
+
+    // Do this for MSBFIRST serial
+    int data = 500;
+    // shift out highbyte
+    shiftOut(dataPin, clock, MSBFIRST, (data >> 8));  
+    // shift out lowbyte
+    shiftOut(data, clock, MSBFIRST, data);
+    
+    // Or do this for LSBFIRST serial
+    data = 500;
+    // shift out lowbyte
+    shiftOut(dataPin, clock, LSBFIRST, data);  
+    // shift out highbyte 
+    shiftOut(dataPin, clock, LSBFIRST, (data >> 8)); 
+
+
+
+Example
+-------
+
+*For accompanying circuit, see the `tutorial on controlling a 74HC595 shift register <http://arduino.cc/en/Tutorial/ShiftOut>`_.*
+
+
+
+::
+
+    //**************************************************************//
+    //  Name    : shiftOutCode, Hello World                         //
+    //  Author  : Carlyn Maw,Tom Igoe                               //
+    //  Date    : 25 Oct, 2006                                      //
+    //  Version : 1.0                                               //
+    //  Notes   : Code for using a 74HC595 Shift Register           //
+    //          : to count from 0 to 255                            //
+    //****************************************************************
+    
+    //Pin connected to ST_CP of 74HC595
+    int latchPin = 8;
+    //Pin connected to SH_CP of 74HC595
+    int clockPin = 12;
+    ////Pin connected to DS of 74HC595
+    int dataPin = 11;
+    
+    void setup() {
+      //set pins to output because they are addressed in the main loop
+      pinMode(latchPin, OUTPUT);
+      pinMode(clockPin, OUTPUT);
+      pinMode(dataPin, OUTPUT);
+    }
+    
+    void loop() {
+      //count up routine
+      for (int j = 0; j < 256; j++) {
+        //ground latchPin and hold low for as long as you are transmitting
+        digitalWrite(latchPin, LOW);
+        shiftOut(dataPin, clockPin, LSBFIRST, j);   
+        //return the latch pin high to signal chip that it 
+        //no longer needs to listen for information
+        digitalWrite(latchPin, HIGH);
+        delay(1000);
+      }
+    } 
+
+