Hi. I just picked up some Nokia 3310 displays off ebay, just 3.5USD a piece, 48x84 pixels with backlight. I'm going to use these displays for a lot of projects from now on as I find them superior to any 7-seg, dot-matrix or numerical LCD display. One thing I didn't find was a library for it so I decided to make one myself. This is the first library I've made so I don't know all the conventions to use etc, but it works just fine if anyone is interested. It writes small 4-digit integers, small characters, big 4-digit integers and big characters as well as having the option to invert text and write directly to the [6][84] data array for custom control. Giving that these displays are so cheap, handy and easy to use I find it odd that I couldn't find a library for it. Have I just not searched for long enough or might there be an interest in the library that I've made?
I have somewhere a Arduino Uno connected to an Nokia 5110, but I did not try your code. Looking at your code, it is very consistent. I like seeing code like that, although I would use more type casting, even when it is not necessary.
You could also cut down on some memory if you change your variable types. I noticed you are using ints in the FOR loops that don't exceed 255, so you can use (byte or unsigned char) and if you need something to start from -1 or go into the negative range and not exceed -127 to 128, then you can use char.
Every little bit of memory you can save, makes a big difference in the long run. Especially if you have large sketches.
