In this installment of Design Cycle, we will reduce that hundreds of dollars to $30, and eliminate the need for a specialized compiler, external debugger/ programmer, and unique dedicated target hardware. The ME Labs D-Stick The ME Labs D-Stick is a stand-alone development environment that is based on the Microchip PIC16F1937.
The topside of my D-Stick is pictured in Photo 1.
The PIC16F1937 mounted on the D-Stick printed
circuit board (PCB) is packaged in SMT form. The D-Stick PCB translates the PIC16F1937’s SMT format
to the standard Microchip 40-pin DIP format. The
package translation and PCB design allow the D-Stick to be used just as if it were a 40-pin
To keep the D-Stick hardware as simple as
possible, the PIC16F1937’s internal 16 MHz clock is
used instead of an external crystal and associated
load capacitors. To protect the PIC16F1937, a group
of 220Ω resistors isolate the I/O pins that
interface with the PIC18F25K50, which replaces
the external programmer/debugger hardware and
holds the D-Stick’s programmer/debugger/serial
Visual indicators in the form of a couple of
LEDs display the D-Stick’s power and
programming activity. The D-Stick’s PIC18F25K50
communicates with the host PC via USB. Being
curious, I plugged an Ellisys USB analyzer into the
D-Stick-to-PC communications link. I did manage
to find the data exchange packets, but it really
didn’t reveal anything.
What I did find is that the D-Stick’s
PIC18F25K50 is programmed as a HID
downstream device that exchanges data using 64-
byte packets. A USB serial communications
function operating at 115000 bps is also part of
the PIC18F25K50’s USB configuration.
THE DESIGN CYCLE
D-Stick is Delightful for Development
■ BY FRED EADY
56 May 2017
Back in the day, if you wanted to develop with a microcontroller, you had to have deep
pockets. Support for your target microcontroller included purchasing the appropriate
compiler, which was typically high dollar. A hardware programmer/debugger would also
have to be purchased — again high dollar. Unless you already had the target hardware
designed and assembled, to get started you would be forced to purchase the available
development kit that targeted your selected microcontroller. The final price tag for a
minimal set of support tools usually ran in the high hundreds of dollars. To add insult to
injury, the hardware programmer/debugger was dedicated to the code generated by the
companion compiler and could not be used with other devices.
■ PHOTO 1. The D-Stick fits perfectly into a standard 40-pin DIP
socket. This allows the D-Stick to “sit in” as the final target
■ PHOTO 2. The fastest and easiest way to get started with the
D-Stick is to plug it into a solderless breadboard.