[sdiy] Embedded micros

[Byron G. Jacquot]

>um, what are imbeded micro's?  
>
>are they those things that look like a little piece of grey chewing gum 
>rolled in gunpowder that I find on kids toys like zap guns and stuff?  

An embedded microprocessor is usually one that's set up in some "hidden"
application, and runs a specialized program to do whatever task is at hand.
Compare it to an "open" system, like a desktop computer, where you can load
and run all sorts of other software.  They're also usually considered
distinct from DSP chips, which are made for number crunching, though they
may also be hidden in various boxes.

Embedded micros turn up in all kinds of "closed" systems, from the things
that makes the LED in the kid's shoes blink and other toys, up to industrial
machine control.  Most modern synths, drum machines etc have at least one
micro inside, possibly in charge of some analog electronics, or a DSP, or
even generating the sound itself.

It's also common for chips that were once at the bleeding edge of the
desktop/workstation to eventually get spun into embedded chips...the chip
might sprout onboard RAM/ROM/EEPROM etc for storing code and data, and move
some peripherals onboard (some UARTS, 3-wire interface, AD/DA).  With some
modern systems, all you need to supply the processor with is power, and
maybe an RC network for the clock...everything else is internal.  The ol'
6502 is still around in various guises like that, as is the 68000 (ever peek
inside a Palm Pilot?  Not much in there!).

Byron Jacquot