[time-nuts] I want a good micro-controller

Hal Murray hmurray at megapathdsl.net
Wed Aug 13 14:50:53 EDT 2008

> It needs to drive a display of some form (standard LCD is fine but
> other options would be good) and since nearly all my references are
> based on 10MHz it would be nice if it could be clocked at that speed.
> I used to program the Acorn Achimedes and so ARM would be nice and
> since I'm a 20 year experienced C programmer (not C++) then that is
> what I'd like to program it in.

> Thoughts, ideas, comments would be appreciated!

Are you looking for a chip to use in a board you are going to design, or an 
existing board that will do your job, possibly with some hacking?

I'm not up to date on boards.  The mega-donkey looks like a good straw man.  
(I think you need something else to program it.)

Vendors often have inexpensive low end development kits.  (Some of the high 
end boards are quite pricey for a hobby project.)  Here is a sample:
(It needs a programmer too.)

Have you considered using a laptop?  Older (real old?) ones had printer ports 
so you could get a PPS in.

Assuming you are looking for a chip:

I know of 3 families of 8 bit chips: AVR from Atmel, PIC from Microchip, and 
8051s from several vendors.  It's a cut-throat market area.  I think they all 
make chips that are roughly equivalent.

If you need something more powerful, the ARM chips are probably the way to go.

I like the Atmel chips, both ARM and AVR.  Their I/O units are generally not 
too quirky and the documentation is pretty good.  Digikey carries them.

They usually have a one page sheet that compares all of their chips.  Here is 
a sample, but it doesn't show the I/O stuff.

> Oh and cheap! 

I don't think the price of the CPU chip will be a big deal for a low volume 
project.  Things get interesting if you want to buy a million of them.

Often, a vendor will make several versions of a chip with the same I/O but 
different sizes of RAM/Flash.  For a hobby project, I'd get the biggest one, 
just in case.

Odds and ends:
  If you have a PPS, you probably have 10 MHz too.  If you can use that for 
your CPU clock, then you don't have to worry about calibration.

  Running off batteries won't be a problem.  All your power will go into the 
backlight for the LCD.  :)

These are my opinions, not necessarily my employer's.  I hate spam.

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