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USING A BOOT MONITOR IN EMBEDDED SYSTEMS

Part 1ıConstructing the Platform
by Ed Sutter

Start ı The Typical Package ı What are the Alternatives? ı Key Ingredients ı MicroMonitor Run Time Startup ı Just After Reset ı Establish Exception Handlers ı I/O Initialization ı Flash Memory Drivers ı Sources and PDF

How many of you can recall the days of standing around in the hallways and discussing the usefulness of a high-level language in an embedded system? If you really want to date yourself, I guess you could go one step further back and recall some discussion on the need for an assembler; but we wonıt go there because my recollection doesnıt go back that far (right!).

Iım starting with this because, to a certain degree, the use of a monitor in an embedded system is also fading into the past. When talking with folks, I try to encourage the use of a monitor, but I find that itıs slowly being taken over by bootroms supplied by hardware and software houses that do the basics for you. Hopefully, if you are on the side that says "away with the monitor," this series will at least get you thinking about it again. If you are already a monitor advocate, then some of this discussion may provide you with ideas for improving your current implementation.

Like all good designs, chances are there were many steps leading up to that design that werenıt all good, but through them, lessons were learned and modifications were made. In some cases, the lesson was to bail out and opt for an alternate approach. And in other cases, the final design was a solid one simply because of what was learned during some of its preceding implementations.

Based on this premise, letıs start by discussing what is typically seen in a monitor and try to understand just what is good and what is bad about most monitor implementations. Hopefully, from there, youıll agree that instead of bailing out you can come up with a monitor design that provides a powerful embedded system development platform that will be useful through the life of the project.

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