Nokia 5110 LCD

I bought a SparkFun Nokia 5110 LCD through InMotion. Both sites have the datasheet and example documentation for how to use it.
Adafruit also sells this and documents its use with another excellent Ladyada tutorial.

Here it is with connectors already soldered:


The soldering is pretty bad. Maybe I should buy a new tip for my soldering iron...

This screen supports direct connection to an Arduino (5V), but in doing so we push it to the datasheet defined limits, so to it is best to reduce all signals to a confortable 3.3V.

My Arduino Duomilanove only outputs 5V signals, so in order to translate those signals to 3.3V, the simplest way is to use a Voltage Divider.
I used this site to calculate the best resistor values to use for this case (10kOhm and ~5kOhm).
Adafruit offers a free level shifter with the LCD that can be used as a more efficient Voltage Divider.

Also to light up the 4 leds used as backlight I used a 22Ohm resistor, so that I could connect to a 5V signal on the Arduino in order to control them with PWM.


And here it is using the Arduino example code 2: