Software Diagramming in Embedded Systems

afd100 writes: I work for a medium sized company building embedded systems using C. As of yet, we do not have a great design methodology, but it is something we're working on. For the last 7 years now, we've been documenting our embedded software in an IEEE'esque Software Detailed Design, and using a very cryptic block diagram to explain our software. What does the embedded software community at large currently use to graphical represent their software or do they even try this? Since the programming is functionally decomposed, is UML the right way to go?