Python code for talking to character based LCDs.
The I2c_Lcd class allows for talking to i2c based LCDs.
This was tested on a BeagleBone Black using a 2 x 16 LCD with an i2c module similar to this one.
This code was adapted from some C code that I had written previously for the AVR.
To install on your BBB:
git clone https://github.com/dhylands/python_lcd.git
cd python_lcd
sudo pip install -e .And to test:
sudo lcd/i2c_lcd.pySince my LCD was a 5v device, I used a level converter to convert from BBB's 3.3v to the LCD's 5v.
I put together some [photos here] (https://picasaweb.google.com/115853040635737241756/PythonI2CLCD?authkey=Gv1sRgCLyZoJ3_uPjiXA)
Coming from the BeagleBone Black the wire colors are:
Color Pin Name
------ ----- ------
Black P9-1 GND
Red P9-3 3.3v
Orange P9-7 SYS_5V
Yellow P9-19 SCL
White P9-20 SDA
The photo shows Orange connected to P9-5. I discovered that P9-7 is controlled by the onboard voltage regulators, so when you do a "sudo poweroff" then SYS_5V drops to 0v when the BBB is powered off. P9-5 (VDD_5V) remains at 5v after the BBB is powered off.
And the colors going to the LCD are:
Color Name
------ ----
Black GND
Red 5v
White SDA
Yellow SCL
I used a SparkFun level shifter (this particular model is no longer available).
Some examples of other level shifters which could be used: