Traditionally, the oscilloscope was the most common hardware tool for debugging embedded systems. While a very good tool for viewing and measuring analog signals, it’s not particular useful for embedded system debugging. An LED attached to an I/O pin can server as an almost equally good tool to determine if the application has reached a certain point in the code. Viewing complex signals on pins may show that they appear to be generating the correct signals, but interpreting the actions of the application by monitoring a few pins will likely provide little information, offering slightly more than the burn and learn method. Most embedded systems developers have an oscilloscope on their lab bench, most engineers are familiar with their use, and they can be relatively inexpensive. The drawback of using an oscilloscope is that it can only monitor a few signals on the pins of the embedded application – all other internal CPU actions have to be deduced from a very few clues.