micropython/docs/pyboard/tutorial/lcd160cr_skin.rst

The LCD160CR skin
=================

This tutorial shows how to get started using the LCD160CR skin.

.. image:: http://micropython.org/resources/LCD160CRv10-positions.jpg
    :alt: LCD160CRv1.0 picture
    :width: 800px

For detailed documentation of the driver for the display see the
:mod:`lcd160cr` module.

Plugging in the display
-----------------------

The display can be plugged directly into a pyboard (all pyboard versions
are supported).  You plug the display onto the top of the pyboard either
in the X or Y positions.  The display should cover half of the pyboard.
See the picture above for how to achieve this; the left half of the picture
shows the X position, and the right half shows the Y position.

Getting the driver
------------------

You can control the display directly using a power/enable pin and an I2C
bus, but it is much more convenient to use the driver provided by the
:mod:`lcd160cr` module.  This driver is included in recent version of the
pyboard firmware (see `here <http://micropython.org/download>`__).  You
can also find the driver in the GitHub repository
`here <https://github.com/micropython/micropython/blob/master/drivers/display/lcd160cr.py>`__, and to use this version you will need to copy the file to your
board, into a directory that is searched by import (usually the lib/
directory).

Once you have the driver installed you need to import it to use it::

    import lcd160cr

Testing the display
-------------------

There is a test program which you can use to test the features of the display,
and which also serves as a basis to start creating your own code that uses the
LCD.  This test program is included in recent versions of the pyboard firmware
and is also available on GitHub
`here <https://github.com/micropython/micropython/blob/master/drivers/display/lcd160cr_test.py>`__.

To run the test from the MicroPython prompt do::

    >>> import lcd160cr_test

It will then print some brief instructions.  You will need to know which
position your display is connected to (X or Y) and then you can run (assuming
you have the display on position X)::

    >>> test_all('X')

Drawing some graphics
---------------------

You must first create an LCD160CR object which will control the display.  Do this
using::

    >>> import lcd160cr
    >>> lcd = lcd160cr.LCD160CR('X')

This assumes your display is connected in the X position.  If it's in the Y
position then use ``lcd = lcd160cr.LCD160CR('Y')`` instead.

To erase the screen and draw a line, try::

    >>> lcd.set_pen(lcd.rgb(255, 0, 0), lcd.rgb(64, 64, 128))
    >>> lcd.erase()
    >>> lcd.line(10, 10, 50, 80)

The next example draws random rectangles on the screen.  You can copy-and-paste it
into the MicroPython prompt by first pressing "Ctrl-E" at the prompt, then "Ctrl-D"
once you have pasted the text. ::

    from random import randint
    for i in range(1000):
        fg = lcd.rgb(randint(128, 255), randint(128, 255), randint(128, 255))
        bg = lcd.rgb(randint(0, 128), randint(0, 128), randint(0, 128))
        lcd.set_pen(fg, bg)
        lcd.rect(randint(0, lcd.w), randint(0, lcd.h), randint(10, 40), randint(10, 40))

Using the touch sensor
----------------------

The display includes a resistive touch sensor that can report the position (in
pixels) of a single force-based touch on the screen.  To see if there is a touch
on the screen use::

    >>> lcd.is_touched()

This will return either ``False`` or ``True``.  Run the above command while touching
the screen to see the result.

To get the location of the touch you can use the method::

    >>> lcd.get_touch()

This will return a 3-tuple, with the first entry being 0 or 1 depending on whether
there is currently anything touching the screen (1 if there is), and the second and
third entries in the tuple being the x and y coordinates of the current (or most
recent) touch.

Directing the MicroPython output to the display
-----------------------------------------------

The display supports input from a UART and implements basic VT100 commands, which
means it can be used as a simple, general purpose terminal.  Let's set up the
pyboard to redirect its output to the display.

First you need to create a UART object::

    >>> import pyb
    >>> uart = pyb.UART('XA', 115200)

This assumes your display is connected to position X.  If it's on position Y then
use ``uart = pyb.UART('YA', 115200)`` instead.

Now, connect the REPL output to this UART::

    >>> pyb.repl_uart(uart)

From now on anything you type at the MicroPython prompt, and any output you
receive, will appear on the display.

No set-up commands are required for this mode to work and you can use the display
to monitor the output of any UART, not just from the pyboard.  All that is needed
is for the display to have power, ground and the power/enable pin driven high.
Then any characters on the display's UART input will be printed to the screen.
You can adjust the UART baudrate from the default of 115200 using the
`set_uart_baudrate` method.