You never know what’s going to show up in
your inbox. A recent note from Matt Miller, tooling
engineering manager for Commercial Forged Products,
spurred a look back.
“I have been marveling at the proliferation of
incredibly powerful and precise modules of incredible
varieties that are available these days. The price is
comparatively cheap and, whoa, the bang for the buck
is big,” he wrote.
“I’d be very interested to see someone do an objective
comparison of some or even one piece of equipment
that is available for the hack like me (mechanical
engineer who dabbles with electronics) at a reasonable
price versus what was available 10 years ago,”
he noted.
“Every time I thumb through Electronic Design,
I’m amazed at the range of products that are available
now that are almost commodities (maybe they are for
all I know) today that were seriously cutting-edge just
years ago,” he added.
We exchanged a few e-mails, and I took a look to
see what was sitting around the lab. I decided to go a
bit further back to 1976 to see what developers and
hobbyists had available then.
A LOOK THEN...
One of the oldest single-chip microcontrollers is
the Intel 8748 (Fig. 1). It is an EEPROM version in the
MCS-48 line that eventually led to the 8051, whose
architecture is still found in mainstream micros. I happen
to still have a couple of 8748s in a drawer. They
go back to my times at the RCA Sarnoff Research
Center in Princeton, N.J., when Intel was also rolling
out the 8088 that started the PC revolution.
I don’t remember what the quantity price was,
but they weren’t cheap compared to today’s
small micros, which cost less than four
bits, or 50 cents. Still, we marvelled at
the designs we could come up with
and how small they were then.
There were choices back then but not
the plethora of options available today.
Then, the massive choices were in discretes
and dual-inline packages (DIPs) from
adders to multiplexers. Clock rates were above
a megahertz, though most instructions required
multiple clocks.
AND A LOOK NOW...
Spin ahead to 2006 and we have the Parallax Propeller
(Fig. 2). This eight-core, 32-bit chip consumes
the same 100 mW assuming all cogs (cores) are in
play. Comparisons are hard between such disparate
architectures, but it’s safe to say that the Propeller is
faster by well over a factor of 100.
In one way, the Propeller is similar to the MCS-48
family. Both provided basic parallel interfaces. Serial
ports were implemented in software. Of course,
the Propeller can run a serial line quite a bit faster,
including the ability to drive a VGA display. Also,
each core has significantly more power and resources
than an MCS-48 chip. Plus, the Propeller is easier
to program.
The choices vary widely these days, making a
designer’s selection more interesting. At the other
end of the spectrum lies a host of tiny six-pin micros
that cost less than 50 cents and sip nanowatts in sleep
mode. Skip again to the 32-bit end with a single-core,
Stellaris 32-bit ARM Cortex-M3 from Texas Instruments
for under a dollar (see “32-Bit ARM MCU Hits
One-Dollar Mark” at www.electronicdesign.com,
ED Online 12358).
The venerable Intel 8748H is still available for
$12.95 at Jameco Electronics, or you can check eBay.
By the way, the Propeller is also available in a 40-pin
DIP and costs around $5.
INTEL
JAMECO ELECTRONICS
PARALLAX
TEXAS INSTRUMENTS