On this page you can find software for the Maxim MAXREFDES99# Display Driver Shield, an Arduino & ARM mbed compatible shield with a 16x16 (= 256) LED matrix.

Note that the photo (stolen from by Maxim) shows red LEDs, the board I have has green LEDs.

Also the kit shown on the photo does not include the board that you see under the shield. It does, however, include a 9V 1.3 A USA-only wall-mount power adapter.

This video shows the demo by Maxim running on an Elektor Uno R4. At second 27 the demo shows software brightness control, which works fine on the display but is hard to capture on (phone) video. Note the problem with the 'm' at the end of the video, an easy-to-fix bug in the font.
 

Here is a very short video showing an animation consisting of a sequence of 13 bitmaps. The Arduino source code for it can be downloaded below.
 

Finally a video showing text scrolling with large fonts using the full 16x16 array. The Arduino source code for it can be downloaded below.