[Note] Using 16x2-digit character LCD (1602A) from Python with Raspberry Pi

Overview

--Use Adafruit's Python library to display characters on a 16x2-digit character LCD known as 1602.
https://github.com/adafruit/Adafruit_Python_CharLCD --It's not an I2C connection ** --Any pin that can be used as GPIO on Raspberry Pi can be connected.

environment

Raspberry Pi 2
2017-04-10-raspbian-jessie --sudo apt-get update && sudo apt-get upgrade,
Linux raspberrypi 4.9.24-v7 + # 993 SMP Wed Apr 26 18:01:23 BST 2017 armv7l GNU / Linux

procedure

Connect

LCD Pin :Raspberry Pi pin
 1 VSS * GND
 2 VDD * 5.0V
 3 V0  * (To the pin in the middle of the 10KΩ variable resistor. 5 at both ends of the variable resistor.0V and GND)
 4 RS  : GPIO22 (15th Pin)
 5 RW  : GND (H=Read/L=Since it is Write, Write Only)
 6 E   : GPIO26 (No. 37 Pin)
 7 D0  -Do not use NC
 8 D1  -Do not use NC
 9 D2  -Do not use NC
10 D3  -Do not use NC
11 D4  : GPIO5  (29th Pin)
12 D5  : GPIO6  (31st Pin)
13 D6  : GPIO13 (33rd Pin)
14 D7  : GPIO19 (No. 35 Pin)
15 A   * 5.0V
16 K   * GND

Do not connect the power supply to the Raspberry Pi.
Wire 5.0V, GND and variable resistors ** carefully </ font> **.

Well, check it.

Insert the power supply into the Raspberry Pi with the SD card removed, and try supplying 5.0V.

Turn on the LCD backlight and turn the variable low to change the contrast.

When the power is turned on, ■ is displayed in the upper row and nothing is displayed in the lower row.

Unplug the power supply and wire the rest.

Insert the SD card into the Raspberry Pi, turn the power off and then on again, and start up.

Library installation

sudo apt-get update
sudo apt-get install -y build-essential python-dev python-smbus python-pip git
sudo pip install RPi.GPIO
#
cd $HOME
#Git, Kuro-n.
git clone https://github.com/adafruit/Adafruit_Python_CharLCD.git
#
cd Adafruit_Python_CharLCD
#Installation
sudo python setup.py install

Try using it lightly

Start Python with python [Enter]
Code, copy

#Import this guy. import Adafruit_CharLCD as LCD #Pin settings.Enter the GPIO number lcd_rs = 22 lcd_en = 26 lcd_d4 = 5 lcd_d5 = 6 lcd_d6 = 13 lcd_d7 = 19

#16x2 digits. lcd_columns = 16 lcd_rows = 2

lcd = LCD.Adafruit_CharLCD(lcd_rs, lcd_en, lcd_d4, lcd_d5, lcd_d6, lcd_d7, lcd_columns, lcd_rows) #LCD clear. lcd.clear() #Message display. lcd.message('Hello World!16x2\nQiita.com/mt08/') #Display the cursor and blink lcd.blink(True)


 3. Exit with `Ctrl-D`



## Other
 --When running ʻAdafruit_Python_CharLCD / examples / char_lcd.py`, open it in a text editor and change the pin settings to a good one.
 ――I have 5V, but is GPIO okay ?? <br> ... Maybe. .. .. Since the RW pin is set to GND and it is written only from the perspective of Raspberry Pi, it will not be output from the LCD side ...
 -If you look at [ʻAdafruit_CharLCD / Adafruit_CharLCD.py`](https://github.com/adafruit/Adafruit_Python_CharLCD/blob/master/Adafruit_CharLCD/Adafruit_CharLCD.py), you can see the commands that you can use ... `def` So you define it, right?
 --If you look at the WiringPi (http://wiringpi.com/dev-lib/lcd-library/), does C support it? Like

### Execution example

```py
pi@raspberrypi:~ $ python
Python 2.7.9 (default, Sep 17 2016, 20:26:04) 
[GCC 4.9.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> #Import this guy.
... import Adafruit_CharLCD as LCD
>>> #Pin settings.Enter the GPIO number
... lcd_rs        = 22
>>> lcd_en        = 26
>>> lcd_d4        = 5
>>> lcd_d5        = 6
>>> lcd_d6        = 13
>>> lcd_d7        = 19
>>> #
... #16x2 digits.
... lcd_columns = 16
>>> lcd_rows    = 2
>>> #
... #
... lcd = LCD.Adafruit_CharLCD(lcd_rs, lcd_en, lcd_d4, lcd_d5, lcd_d6, lcd_d7,
...                            lcd_columns, lcd_rows)
>>> #LCD clear.
... lcd.clear()
>>> #Message display.
... lcd.message('Hello World!16x2\nQiita.com/mt08/')
>>> #Display the cursor and blink
... lcd.blink(True)
>>> 
pi@raspberrypi:~ $