That Was Then, This Is Now
Good development tools no longer cost thousands of
dollars, and many of the available microcontroller
compilers are free. My first core set of development tools
included a Heathkit oscilloscope, a Heathkit low
frequency signal generator and an EICO VOM (
Volt-Ohm-Multimeter). My father believed that if I didn’t put it
together, I didn’t know anything about it. So, the EICO
VOM also was assembled by me by hand from a kit. I was
obviously not set up to do any serious digital work. The
closest I got to “digital’ was generating square waves with
the signal generator.
After microcontrollers got my attention, I debugged
with a logic probe and oscilloscope. The logic probe was
used to see if an I/O pin was toggling or presenting a
particular logic state. If I wanted to make sure my RS-232
baud timing or delay routine timing was correct, I would
measure the timing using an oscilloscope.
You can still use a logic probe and oscilloscope to look
at digital signals. However, thanks to the folks at Digilent,
you can get the same and better results from a device
about the size of a hockey puck that you can easily hold in
one hand. Digilent’s Digital Discovery is an oscilloscope, a
wave generator, a voltmeter, a logic probe, a pattern
generator, and a protocol analyzer. I’m not going to
elaborate on the Digital Discovery’s specifications here as
they are available for your reading pleasure on the Digilent
website. So, let’s put the Digital Discovery to work.
The Digital Discovery operates under the control of
Waveforms 2015, which runs on a PC. I’ve downloaded
and installed Waveforms 2015 on my trusty Dell laptop.
My Discovery is shown in Photo 1.
THE DESIGN CYCLE
Putting the Digital Discovery to Work
■ BY FRED EADY
46 June 2017
I love development tools. In the days of the dinosaur, development tools for
microcontrollers were expensive and hard to come by. If you didn’t have $5,000 or more
to spend, your bench didn’t see ANY development tools. It was so bad that when I began
using PIC microcontrollers, I designed and coded my own set of hardware debugging
tools. At that time — to add insult to injury — the PIC assembler cost $99. Instead of
purchasing a license, I resorted to writing my own.
■ PHOTO 1. The Digital Discovery is based on a Xilinx
FPGA and is capable of capturing digital signals in a
number of ways at very high speed. This little box turns
your PC into a multi-function digital test instrument.
■ PHOTO 2. A high speed signal cable is shown wrapped
around the high speed header assembly.