class LCD --- LCD control for the LCD touch-sensor pyskin
=========================================================

The LCD class is used to control the LCD on the LCD touch-sensor pyskin,
LCD32MKv1.0.  The LCD is a 128x32 pixel monochrome screen, part NHD-C12832A1Z.

The pyskin must be connected in either the X or Y positions, and then
an LCD object is made using::

    lcd = pyb.LCD('X')      # if pyskin is in the X position
    lcd = pyb.LCD('Y')      # if pyskin is in the Y position

Then you can use::

    lcd.light(True)                 # turn the backlight on
    lcd.write('Hello world!\n')     # print text to the screen

This driver implements a double buffer for setting/getting pixels.
For example, to make a bouncing dot, try::

    x = y = 0
    dx = dy = 1
    while True:
        # update the dot's position
        x += dx
        y += dy

        # make the dot bounce of the edges of the screen
        if x <= 0 or x >= 127: dx = -dx
        if y <= 0 or y >= 31: dy = -dy

        lcd.fill(0)                 # clear the buffer
        lcd.pixel(x, y, 1)          # draw the dot
        lcd.show()                  # show the buffer
        pyb.delay(50)               # pause for 50ms


Constructors
------------

.. class:: pyb.LCD(skin_position)

   Construct an LCD object in the given skin position.  ``skin_position`` can be 'X' or 'Y', and
   should match the position where the LCD pyskin is plugged in.


Methods
-------

.. method:: lcd.command(instr_data, buf)

   Send an arbitrary command to the LCD.  Pass 0 for ``instr_data`` to send an
   instruction, otherwise pass 1 to send data.  ``buf`` is a buffer with the
   instructions/data to send.

.. method:: lcd.contrast(value)

   Set the contrast of the LCD.  Valid values are between 0 and 47.

.. method:: lcd.fill(colour)

   Fill the screen with the given colour (0 or 1 for white or black).
   
   This method writes to the hidden buffer.  Use ``show()`` to show the buffer.

.. method:: lcd.get(x, y)

   Get the pixel at the position ``(x, y)``.  Returns 0 or 1.
   
   This method reads from the visible buffer.

.. method:: lcd.light(value)

   Turn the backlight on/off.  True or 1 turns it on, False or 0 turns it off.

.. method:: lcd.pixel(x, y, colour)

   Set the pixel at ``(x, y)`` to the given colour (0 or 1).
   
   This method writes to the hidden buffer.  Use ``show()`` to show the buffer.

.. method:: lcd.show()

   Show the hidden buffer on the screen.

.. method:: lcd.text(str, x, y, colour)

   Draw the given text to the position ``(x, y)`` using the given colour (0 or 1).
   
   This method writes to the hidden buffer.  Use ``show()`` to show the buffer.

.. method:: lcd.write(str)

   Write the string ``str`` to the screen.  It will appear immediately.