GETTING STARTED WITHPICs
THE LATEST IN PROGRAMMING MICROCONTROLLERS
■ BY CHUCK HELLEBUYCK
IMPROVING THE PICKIT 2
I’ve recommended the Microchip PICkit 2 Starter Kit for the projects in this
column for quite a while, but along the way I improved the development
board for my own projects. The one thing I always wanted to add was a
breadboard area, so I modified the development board included with the
Starter Kit — it’s called the low pin count development board. I decided to
use this board for all the projects in my next embedded C book (Beginner’s
Guide to Embedded C Programming – Volume 2) which I hope to have
released by the time you read this. I’ve used this board in a few Nuts & Volts
articles as well, but never explained how I built it. This month, I’ll give you all
the details to create your own version of this board.
Figure 1 shows the completed board. Though it looks
simple, this board is incredibly handy for developing code
or sections of your larger projects. I also add a twist to this
by showing how to create stackable versions, to make it
easier to save your hardware for a later date.
The parts required to build the development board
are shown in Figure 2. The whole thing starts with the low
pin count board and then I add one of the smallest
breadboards I could find that happens to fit very nicely on
the board. Additionally,
the board has pads for
adding jumpers in series
with the LEDs. The board
also has extra pads that
connect to the 20-pin socket pins. This gives us access to
the PIC16F690 microcontroller’s I/O, but I wanted these
to be socketed so I could just use jumper wires from those
pads to the breadboard. A couple of 10-pin headers get
that job done.
You can get these parts from various sources, but I
got most of them through Jameco Electronics (www.
jameco.com). The 10-pin female headers are actually
16-pin headers that I cut down to 10 pins with a side
cutter. I lost one pin from the cut and ended up with a
10- and a five-pin header from that original 16-pin header.
The first step I took was to cut the jumper bypass
traces near the LEDs. I sliced the trace on both sides and
then actually used a broken-tip X-ACTO knife to push
forward and rip the isolated trace from the board
(see Figure 3A). Next, I used an ohmmeter to
verify that each trace was a successfully opened
circuit (see Figure 3B). Once you solder the
header in place, you can’t get to the traces very
easily. This is an important step that I learned the
hard way. I actually had a small amount of trace
still connected on one of the LEDs the first time I
tried this, because I was too impatient to verify it
with an ohmmeter.
The next step is to solder the 2-pin headers
in place. It is a little tricky to get these straight.
You really need three hands to do this, but I
■ FIGURE 1. Finished
68 July 2009
■ FIGURE 2. PICkit 2 modification kit.