[time-nuts] Follow-up question re: microcontroller families

Jim Lux jimlux at earthlink.net
Sun May 26 12:18:38 EDT 2013

On 5/26/13 9:00 AM, Chris Albertson wrote:
>> But for many applications, the inevitable overhead
>> (power, heat, external components, OS, etc) simply
>> eliminates the gain of having a better/faster CPU.
>> Sometimes I end up using a 6 or 8 pin PIC with only
>> a few lines of code to to solve complex problems where
>> a (F)PGA/CPLD design would be a lot of work and a
>> 16/32bit microcontroller simply overkill.
> As it turns out there are a LOT more simple jobs than there are
> complex jobs.  This is why they make and sel a lot motr 8-t
> controllers than they sell 32-bit controllers.
> For example I want to control the cooling fan for a rubidium
> oscillator's heat sink.   I only need three pins, 1) the temperature
> sensor, 2) Fan tachometer pulse, fan voltage.  A $1 "tiny AVR" 8-pin
> chip can handle this just fine and we are talking about 20 lines of
> code maybe after the pins are set up.  Using an ARM and running an OS
> would be silly overkill.

The other thing is packaging and peripherals..not to mention development 
time.  It might be more "cost effective" (where cost is some complex 
conglomeration of your time and money) to always use the same part, even 
if overkill.

Some people are happy to layout a new PCB, get it fabbed (or make it 
themselves) or deadbug it.  Others might want a board with terminal 
strips.  Or you might want something that you have a box for or maybe 
you like mounting it inside.

I think everyone has their favorites, and most folks tend to have 
relatively few candidates at any given time (it's difficult to switch 
among various processors on a day to day basis).  Right now, I tend to 
use Matlab on PCs for big things, with some python.  For smaller needs, 
I've been using lots of Arduino Uno R3s and Teensy3s, because of the 
packaging.  Both using the Arduino semi-C tool chain and also the 
non-arduino compilers.  (having a USB boot loader, etc, does make life 

I've used PICs and Rabbits in the not too recent past, but the Rabbits 
don't have as nice a development environment, and there's no equivalent 
of the $20 Arduino, nor the plethora of cheap interfaces to things like 
relays and what not.

I haven't looked much at whether a low cost PIC on a board with 
peripherals is available. They've always been a "build a circuit" either 
with perfboard, deadbug, or small PCB, and that makes it take a few more 
hours or days.

For the "I want to finish the project this weekend starting Saturday 
afternoon", the whole arduino world is pretty convenient, at least as 
far as getting the hardware put together and a first load of software 

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