Where did you start with Micro controllers?

westfw:

Printronix did make one the earliest 'dot matrix' printers in 132 column version. Dec also made an early 132 column dot matrix for their minicomputer systems, the famous LA-36 printer.

The Printronix I'm thinking of was a high-speed lineprinter replacement with an entire row (?) of dots.
The LA36 was a terminal (keyboard/etc), ran at 30cps, and had the more typical arrangement with a single column of dots on a moving printhead...

LA36 Engineering manual: PDP-8 Document Search Results

Here is the picture of the Printronix I worked on a little, but don't recall the exact hammer arrangement, seem to recall something spinning pretty fast inside, but then again there were so many different printers back at the time.

http://www.google.com/imgres?q=printronix&hl=en&sa=X&rlz=1T4GGLL_enUS373US373&biw=1055&bih=720&tbm=isch&prmd=imvns&tbnid=eq-_kQsJQQiOPM:&imgrefurl=http://www.fib.upc.edu/retroinformatica/exposicio/ordinadors/Printronix-P600.html%3Flang%3Dca&docid=-GQooXnZlvA-7M&imgurl=http://www.fib.upc.edu/retroinformatica/exposicio/ordinadors/Printronix-P600/mainColumnParagraphs/0/image/IMG_2158%252520(Custom).JPG&w=620&h=827&ei=7dI5T_rTIYOZiQKqmZSTDA&zoom=1&iact=rc&dur=63&sig=108332181031703398911&page=3&tbnh=167&tbnw=119&start=35&ndsp=18&ved=1t:429,r:1,s:35&tx=52&ty=70