Obviously this wont be as idiot-proof as digitalWrite() is, but we think you can handle it. Our second tip is for a set of OLED displays from 4dsystems sold as Arduino Shields.

From your downloads, open the example labeled as Example1-ReadButtons_WriteLEDs.ino.This example reads a switch and writes to the non-addressable LED using the PCA9554 I/O I 2 C Expander.. For users ...