Updated value, docs, example

Author: kattni

README.rst

@@ -13,7 +13,7 @@ Introduction
     :target: https://travis-ci.org/adafruit/Adafruit_CircuitPython_74HC595
     :alt: Build Status
 
-.. todo:: Describe what the library does.
+CircuitPython driver for 74HC595 shift register.
 
 Dependencies
 =============
@@ -29,7 +29,26 @@ This is easily achieved by downloading
 Usage Example
 =============
 
-.. todo:: Add a quick, simple example. It and other examples should live in the examples folder and be included in docs/examples.rst.
+.. code-block:: python
+
+    import board
+    import adafruit_74hc595
+    import busio
+    import digitalio
+    import time
+
+    spi = busio.SPI(board.SCK, MOSI=board.MOSI)
+
+    latch_pin = digitalio.DigitalInOut(board.D5)
+    sr = adafruit_74hc595.ShiftRegister74HC595(spi, latch_pin)
+
+    pin1 = sr.get_pin(1)
+
+    while True:
+    pin1.value = True
+    time.sleep(1)
+    pin1.value = False
+    time.sleep(1)
 
 Contributing
 ============

adafruit_74hc595.py

@@ -20,7 +20,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 # THE SOFTWARE.
 """
-`Adafruit_74HC595`
+`adafruit_74hc595`
 ====================================================
 
 CircuitPython driver for 74HC595 shift register.
@@ -53,7 +53,7 @@
 
 class DigitalInOut:
     """Digital input/output of the 74HC595.  The interface is exactly the
-    same as the digitalio.DigitalInOut class, however note that by design
+    same as the ``digitalio.DigitalInOut`` class, however note that by design
     this device is OUTPUT ONLY!  Attempting to read inputs or set
     direction as input will raise an exception.
     """
@@ -71,23 +71,22 @@ def __init__(self, pin_number, shift_register_74hc595):
     # in this case.
     # pylint: disable=unused-argument
     def switch_to_output(self, value=False, **kwargs):
-        """DigitalInOut switch_to_output"""
+        """``DigitalInOut switch_to_output``"""
         self.direction = digitalio.Direction.OUTPUT
         self.value = value
 
     def switch_to_input(self, **kwargs):  # pylint: disable=no-self-use
-        """Do not call switch_to_input"""
+        """``switch_to_input`` is not supported."""
         raise RuntimeError('Digital input not supported.')
     # pylint: enable=unused-argument
 
     @property
     def value(self):
-        """Do not call value"""
-        raise RuntimeError('Digital input not supported.')
+        """The value of the pin, either True for high or False for low."""
+        return self._shift_register.gpio & (1 << self._pin) == (1 << self._pin)
 
     @value.setter
     def value(self, val):
-        # Only supported operation, writing a digital output.
         gpio = self._shift_register.gpio
         if val:
             gpio |= (1 << self._pin)
@@ -97,12 +96,12 @@ def value(self, val):
 
     @property
     def direction(self):
-        """ALWAYS an output!"""
+        """``Direction`` can only be set to ``OUTPUT``."""
         return digitalio.Direction.OUTPUT
 
     @direction.setter
     def direction(self, val):  # pylint: disable=no-self-use
-        """Can only be set as OUTPUT!"""
+        """``Direction`` can only be set to ``OUTPUT``."""
         if val != digitalio.Direction.OUTPUT:
             raise RuntimeError('Digital input not supported.')
 

docs/index.rst

@@ -23,14 +23,10 @@ Table of Contents
 .. toctree::
     :caption: Tutorials
 
-.. todo:: Add any Learn guide links here. If there are none, then simply delete this todo and leave
-    the toctree above for use later.
-
 .. toctree::
     :caption: Related Products
 
-.. todo:: Add any product links here. If there are none, then simply delete this todo and leave
-    the toctree above for use later.
+    74HC595 Shift Register - 3 pack <https://www.adafruit.com/product/450>
 
 .. toctree::
     :caption: Other Links

examples/74hc595_simpletest.py

@@ -0,0 +1,18 @@
+import time
+import board
+import busio
+import digitalio
+import adafruit_74hc595
+
+spi = busio.SPI(board.SCK, MOSI=board.MOSI)
+
+latch_pin = digitalio.DigitalInOut(board.D5)
+sr = adafruit_74hc595.ShiftRegister74HC595(spi, latch_pin)
+
+pin1 = sr.get_pin(1)
+
+while True:
+    pin1.value = True
+    time.sleep(1)
+    pin1.value = False
+    time.sleep(1)