25+ Posting Member
An Uno on Steroids
Have you gotten to the point where you have run out of resources using an Uno or Mega? If so, you might want to take a look at Digilent's line of ChipKIT uP boards. Here's a quick overview of the Uno32:
* 80 Mhz 32-bit PIC32 uP
* 128K Flash, 16K SRAM
* 42 available I/O pins
* two user LEDs
* 12 analog inputs
* 3.3V operating voltage
* 7V to 15V input voltage
* +/-18mA DC current per pin
Two of the ChipKIT (CK) boards (Uno32 & uC32) use the Arduino Uno form factor while the third (Max32) uses the Mega2560 form factor. All three board accept Arduino compatible shields.
There are a number of advantages to using one of these boards: speed, storage, number of I/O pins. CK boards use the same IDE as Arduinos. The IDE has been altered to support PIC32 processors. Cost of the boards is right in line with the Uno & Mega2560.
Be Warned -- there are drawbacks to using these boards ---
* 3.3v operation rather than 5v. However, all pins are 5v tolerant so you can hook up 5v inputs to any I/O pin. The 3.3v output voltage exceeds the level needed by 5v logic to be recognized as a logic 1.
* I/O pins can only sink/source +/- 18 mA rather that 40 mA like Arduinos. Digilent actually recommends limiting current draw to +7/-12 mA. Total sink/source current is limited to +/- 200 mA.
* ADC inputs are clamped to 3.3v so that means that 5v analog values will need to scaled down to 3.3v.
* I've read that some Arduino shields don't work with the CK boards. I don't use shields so i haven't paid any attention to which ones work and which ones don't.
* I know that some 3rd party Arduino libraries won't work. They talk directly to uP control ports which are different in PIC32 processors. This type of code will need to be modified to work with CK boards.
* Arduino protoshields won't work because they lack they extra I/O pins. However, NKC Electronics has protoshields that are made for CK boards.
The following.libraries are supplied with the IDE:
In summary, CK boards are for the advanced user who might need to do some hardware interfacing and/or modify existing software. The payoff can be worth the it. An example -- I ported Adafruit's 2.8" TFT LCD library to a CK uC32. This supplied graphics demo program runs NINE times faster than on an Arduino Uno!
Here's a link to the CK boards. If you click on "More Info" for a board you'll get more data plus download links for manuals, schematics, etc.
Cheers - Doug