Page 143 - The Art of Designing Embedded Systems

130 THE ART OF DESIGNING EMBEDDED SYSTEMS

other is only for PCB work and always has a new, sharp blade. Keep 50 or
100 spare blades in your drawer, since PCB work invariably breaks the
very sharp and very essential pointy end off in no time.

Planning
Engineers have managers, who “run” projects, ensuring that re-
sources are available when needed, negotiate deadlines and priorities with
higher-ups, and guide/mentor the developers toward producing a decent
product on time. Planning is one of any manager’s main goals. Too often,
though, managers do planning that more properly belongs to the engineers.
You know more about what your project needs than your boss ever will;
it’s silly, and unfair, to expect him to deal with all of the details.
There are many great justifications for a project running late. In en-
gineering it’s usually impossible to predict all of the technical problems
you’ll encounter! However, lousy planning is simply an unacceptable,
though all too common, reason.
I think engineers spend too much time doing, and not enough time
thinking about doing. Try spending two hours every Monday morning
planning the next week and the next month. What projects will you be
working on? What’s their status? What is the most important thing you
need to do to get the projects done? Focus on the desired goal, and figure
out what you need to do to get there. Do you need to order parts? Tools?
Does some of your test equipment need repair or calibration?
Find the critical paths and do what’s required to clear the road ahead.
Few engineers do this effectively; learn how, and you’ll be in much higher
demand.
When you’re developing a rush project (all projects are rush pro-
jects . . .), the first design step is a block diagram of the each board. From
this you’ll create the schematic, then do a PCB layout, create a bill of
materials, and finally, order parts for the prototype.
Not. The worst thing you can do is have a very expensive quick-turn
PCB arrive, with all of the components still on back order. The technicians
will snicker about your “hurry up and wait” approach, and management
will be less than thrilled to spend heavily for fast-turn boards that idle
away the weeks on a shelf.
Buy the parts first, before your design is complete. Surely you’ll
know what all of the esoteric parts are-the CPU, odd analog components,
sensors, and the like. These are likely to be the hardest and slowest to get,
so put them on order immediately.