RoadTest: chipKIT™ Pi
Author: rwslaugh
Creation date:
Evaluation Type: Evaluation Boards
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: Alamode
What were the biggest problems encountered?: None
Detailed Review:
I would first like to thank Element-14 for the opportunity to RoadTest the chipKIT Pi.
The Raspberry Pi is a marvelous single board Linux based computer. However, when it comes to I/O to connect to outside hardware it lacks flexibility. The chipKIT Pi helps in this regard by being an interface between the Pi and the outside world.
To put it very simply, the chipKIT Pi is an Arduino clone that connects to the Raspberry Pi. In essence, it’s like connecting an Arduino to the Pi, though that is simplifying things to a great detail. Another product on the market already does this, the Alamode. The main difference when looking at the Alamode and the chipKIT is the processor used. The chipKIT uses the PIC processor, a popular processor among hobbyists due to its ease of use and programming. For some of this review I will be comparing the chipKIT to the Alamode.
Getting started with the chipKIT is simple to do, especially considering the support web site has a .iso download for a Raspberry Pi OS that has the programming IDE – MPIED – already installed. While it is possible to load the IDE on an already imaged system, the package deal makes start up much easier. One must always remember to run the sudo update/upgrade commands after initial start up to make sure everything is the latest version. From the standpoint of getting started, I would say that this and the Alamode are about even. With the Alamode you can install the Arduino IDE directly on the Pi, but interfacing to the Alamode is a bit clunkier – depending on if you use I2C or make it look like a serial port connection.
The chipKIT connections are handled a bit more directly, which saves port space in the programming as well as makes things a bit more seamless with the software programming and control.
The chipKIT provides a great amount of flexibility in how some connections are managed. Jumpers on the main board provide the user the ability to change how individual pins are connected. If the hobbyist would like to take this further, one could certainly program a relay to act as the jumper and change the assignment in programming, thus allowing more flexibility in program control.
The chipKIT creates more I/O for the Raspberry Pi to interface with. This is its strongest point. However, much of that I/O is still 3.3V tolerant. (There are a few pins 1, 14-18 that are 5V tolerant.) The Alamode allows connection of 5V to I/O pins. Granted, this isn’t a huge deal as interfacing sensors needs to be done in any case, however a lot of the hobbyist electronics sensors and items are at 5V levels, so using 3.3V is a change for many.
One of the biggest drawbacks to the chipKIT, in my opinion, is the procedure to program it from MPIDE. To program the board, jumpers must be checked and a BOOTLOAD-EN button must be pressed down along with RESET. In other words, you must be able to work these buttons – or pins – when programming. Conversely, the Alamode can be programmed simply and at any time without the use of hands on button pressing. To me, this is a much better way to handle the programming of a board that might be installed in a system that can only be accessed remotely.
Overall, the chipKIT Pi gives added use to the Raspberry Pi which is something it needs. The chipKIT excels at flexibility of use with jumper selectable options, and has the ability of being a powerful I/O interface given the use of the PIC processor. The PIC processor also has more memory and some handy integrated peripherals that allow the user to create some advanced projects a bit more easily than with Arduino.
Some of the drawbacks include the 3.3V tolerance of many of the pins, meaning that while the chipKIT is in a form of the Arduino, it won’t interface with many of the shields easily. Another drawback is the programming aspect needs hands on help (unless one was to replace the switches with relays controlled by another processor).
In the end, it all comes down to what you want to do with it. If I needed a little more power from a micro and some built in toys to go along with it, the flexible chipKIT would be what I want. However, if I wanted something that I can change the programming in a little easier and that would interface with more of the shields on the market today, I would stay with the Alamode.
