LCD Plug (v1)
The LCD Plug is a small board which is designed to sit piggy-back on an HD44780-compatible LCD display with 16-pin connector - the plug is based on the same MCP23008 as the Expander Plug:
The backlight can be controlled via software to reduce power consumption. A BC817 is now used as switch, it can drive up to 500 mA for the backlight. The driver software and an "lcd_demo" example sketch is included in the Ports library.
An I2C bus running at 3.3V is used for I/O, with all the power and signal lines brought out to to both sides of the board to allow daisy-chaining with other I2C-conformant boards.
For additional details, see http://news.jeelabs.org/2009/11/01/lcd-plug/
CONFIGURATION
The I/O expander chip on this plug is set to respond to I2C address 0x24.
The logic supply voltage has to be jumpered to either the PWR or the +3V pin.
The backlight voltage has to also independently be set to either PWR or +3V.
There is room for a backlight current limiting resistor, or use a jumper to bypass it.
And lastly, there is a mini trimpot on the board to adjust the LCD contrast level.
HEADER PINOUTS
DESIGN INFO
Dimensions: 21.1 x 41.9 mm
CadSoft EAGLE design files:
http://jeefiles.equi4.com/jlpcb-043.sch
http://jeefiles.equi4.com/jlpcb-043.brd
Schematic as PDF: http://jeefiles.equi4.com/jlpcb-043.pdf
This plug can be operated at 5V as well as 3.3V.
This board uses the conventions of a JeePlug and can be used with the ports on a JeeNode. It can also be used with other boards and MCU's, if you hook it up properly and adapt the interface code for it.
WHERE TO GET IT
http://shop.jeelabs.com/products/lcd-plug