For developing embedded systems with communicating hardware, a
logic analyzer provides the capability of observing the actual communication
events between two hardware components. Essentially, a logic analyzer “listens”
to a set of digital signals until a trigger event occurs and then captures a
window of data around the trigger event. The software associated with a logic
analyzer allows us to interpret the captured data. In the simplest case a trigger
event might be a the occurrence of a transition on a signal – in the case of
USART communication, every transmission event begins with a falling transition.
Throughout this book we use the Saleae Logic analyzer.