[time-nuts] Good (cheap) PIC chip choice for project?

Jim Lux jimlux at earthlink.net
Sat May 25 10:57:42 EDT 2013

On 5/25/13 7:22 AM, Bob Camp wrote:
> Hi
> PIC's have been around for a *long* time. The PIC16's came early on and were followed by the PIC18's. Both are a bit dated at this point. The PIC24's and dsPIC33's are actually very similar parts. The PIC33's form a third family pretty much on their own. A modern version of the Microchip programmer will flash any of the parts. I have never seen a cheap eprom programmer that will program a PIC. The Microchip programmers are dirt cheap, so that's not a real problem.
> I'd strongly recommend getting one of the starter kits for the dsPIC33 and play with it for a while. It should come with a cpu, a programmer, and a ton of information. The toolchain is pretty simple to use and it's free.
> -----------------
> All that said, the Arduino empire is pretty hard to beat when it comes to mashing together a simple little light blinker. The key issue is being able to use cheap China assembled boards off of the auction sites.  Time wise, and even cost wise it's better than doing layouts and soldering up stuff. Another option are the demo boards that the semiconductor companies flog off for next to nothing. The Freescale Freedom board ($12) is one example out of hundreds. The project cost is *never* about the CPU, it's always about all the other stuff around it.
> If the objective is to complete a very simple, low powered project and be done with it, go with the Arduino. If the objective is to learn an empire, be very careful about which empire you pick. The ARM boys are quickly gobbling up a lot of territory that once was populated by a number of competing CPU's. Learning this stuff, and getting good at it is a significant investment of time.

If you're interested in ARM (in the long run), and find the arduino 
ecosystem interesting :there are enormous numbers of add on "shields" 
for Arduino, and lots of example code of varying quality around.

take a look at the Teensy3 from PJRC.. $19, it's a Freescale Kinetis 
microcontroller with ARM, a fair amount of RAM and flash, but can use 
either the Arduino IDE (teensyduino.. has all the libraries, in source, 
to support the plethora of onchip peripherals in the Kinetis) or native 
tools for the ARM.

One Arduino peripheral that's not readily available, and would be of 
interest to time-nuts, is a high resolution DAC.  the Arduino (and 
teensy, for that matter) have the usual PWM.  You can get a I2C 
interface MCP4725 12-bitDAC from adafruit on a little daughter card 
(with bypass caps, etc.), but I've not found something like a low noise 
16bit DAC.

A decent DAC and the teensy, and I think you could do a very nice 
Disciplined XO.. the Kinetis has a pretty complete set of 
counters/timers/what-have-you that you can interconnect by setting bits 
in the hundreds of control registers, once you figure out how (yep, 
you'll love that 1600 page manual)

More information about the time-nuts mailing list