Display - 20 characters per row, 4 rows
Voltage - 5v only required
Current - 135mA typ. with backlight on
Modes - I2C or 9600 baud Serial
Keypad - Automatic scanning of a 3x4 matrix keypad
Custom characters - up to 8 custom characters easily defined
Backlight defaults off, and can be turned on under software control
Overview
The I2C and serial display driver provides easy operation of a standard 20 x 4 LCD Text display. It requires only a 5v power supply and the two data connections for either mode, freeing up pins on your processor.
Many useful text formatting functions are provided and also the ability to put together custom characters into memory which can be called off as required.
There is a 100 byte FIFO buffer to ensure a minimum of delay in writing to the display.
The LCD05 controller is our new generation LCD display driver and adds additional features to our previous LCD03 driver while being fully compatible in both software and pin-out.
Connections
Connection diagram of the LCD05.
Serial/I2C Mode selection
A single jumper link is used to select Serial or I2C mode. When the jumper is present (factory default) the module is in serial mode. When the jumper is removed the module is in I2C mode. The mode jumper is only checked as part of the power-up sequence, so make sure the display is off before changing modes. If you change the link position while the module is powered, nothing will change until next time you switch on.
FIFO
Because the I2C communications operate faster than the display can accept data, all commands and text you send to the display are placed in the FIFO (First In, First Out) buffer. This data is sent to the display as fast as it will accept it. The FIFO is 100 bytes in length and the number of free bytes can be returned in either mode. When sending lots of text to the display, you should check the number of free bytes so you don't overflow the buffer. If the buffer does overflow, the excess bytes are ignored. The FIFO buffer exists in Serial mode too, but at 9600 the display is fast enough and you are unlikely to need to check it.
I2C Operation
I2C Bus
The I2C display is located on the I2C bus at an address of 0XC6. The SCL and SDA lines should have pull-up resistors on them somewhere on the bus. You only require 1 pair of resistors for the whole I2C bus, not specifically for the LCD05. They are normally on the master controller and you may already have them. If not, anything between 1k8 and 10k should work. I recommend 1k8 for best noise immunity. I2C mode is compatible with SMbus voltage levels.
Full Documentation HERE
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