A newbie here. After reading a small portion of the discussion, this question comes up i my head, is the cost of microcontroller a very important issue in terms o picking the right one? How much a microcontroller CAN contribute to whole product?
Or is it the functionality, speed, power consumption and developmen toolchain userfriendly-ness more important in the decision?
I am thinking about using Cortex M3 for my server cabinet temp controlle project, is it a bad choice in any context?
Like all things it depends on the end application. I've worked in an Automotive environment and where we were developing a high volme product of maybe 500k units/year for a relatively mature application then a $3 micro. is very sgnificant for a total product selling price of maybe $40. On the other hand I've also worked on a product with a volume of only 1000/yr and product selling price of around $1k so then the $10-$15 micro. isn't so significant. In this case it was a very new technology where factors such as reliability and safety were far more important than cost.
I believe military and medical applicaions tend to be even less cost sensitive for the individual components.
If you're building 100 of something, _ever_, and you can save $10000 worth of engineering time by spending $20 more per processor, you've just saved $10000 - $2000 = $18000, and you're a hero.
If you're building 100K parts/year, then spending $10000 worth of engineering time to save one thin dime per finished part is a break-even. If you can save a quarter per finished part -- you're a hero.
Now go back to that first case, and ask yourself if spending $10000 of engineering time to save $250 over the life of the product is a good thing or a bad thing...
You should _always_ consider how many parts are going to be made, and how much of a hurry you are in to get working devices on the market. You'll _always_ be faced with having to spend money to save money -- it's just a question of whether the smart money gets spent on a (relatively) huge processor larded with resources to ease the development burden, or whether the smart money gets spent on development to use the thinnest processor possible.
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Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
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"Applied Control Theory for Embedded Systems" gives you just what it says.
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I just did and find them impressive, especially if the manufacturing is 24/7 forever. It must be a challenge to find components in that quantity (0.9 Gparts/year).
I didn't think IC manufacturers could turn out parts at that rate. If they can, I'd think you'd need to be mouth-of-the-factory to keep delivery logistics in hand.
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