Make Your Robot’s
Wires Extinct
by Fred Eady
Way back when dinosaurs roamed the hills of Tennessee, I was learning how to wire
up tube and transistor circuits. There was no such thing as ExpressPCB. In fact, there
was no such thing as a BBS or the Internet. Only the professional magazine writers of
the day with access to a printed circuit board house could muster an article that
included a project mounted on a fancy copper clad piece of fiberglass. Meanwhile, I
continued to string wire between circuit points and electrically seal them with solder.
Years passed. The dinosaurs died. Dial-up BBS sites gave way to the Internet and
professional printed circuit board houses reached out to folks like you and me.
Telephones lost their wires and personal computer Ethernet cables disappeared.
I’ll bet you’re still wired to that microcontroller that you’re going to use to control
that rolling aluminum slab you call a robot. Read on and I’ll show you how to lose
the wires.
www.servomagazine.com/index.php?/magazine/article/june2011_Eady
A New 8051-based Powerhouse
Before we put on our pointy hats and discuss the
radios, I’m going to introduce you to the SPECTRUM ACE
2a — a really neat, self-contained computing platform from
I2I Controls. ACE is short for Advanced Control
Environment. The SPECTRUM ACE 2a single board
computer is going to be right down your alley. As a robot
FIGURE 1. Some
things work so
very well that they
never need to
change. This is the
same circuit I cut
my 8048 and 8051
teeth on 25 or so
years ago.
A15
A14
A13
A12
74HC20
74HC02
P3.5/A16
54 SERVO 06.2011
DS89C450
AD0
AD1
AD2
AD3
AD4
AD6
AD7
AD5
ALE
1
11
2
3
4
5
6
7
8
9
OE
LE
1D
2D
3D
4D
5D
6D
7D
8D
19
18
17
16
15
14
13
12
1Q
2Q
3Q
4Q
5Q
6Q
7Q
8Q
74HC573
A9
A10
A11
74HC138
A
B
C
G1
G2A
G2B
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
head, you are ALL about control, and that’s what the
SPECTRUM ACE 2a is designed to do.
The ACE 2a is the largest microcontroller platform in
the SPECTRUM ACE family. The ACE 2a is based on the
Dallas Semiconductor DS89C450 ultra high speed Flash
microcontroller. If you roamed with the dinosaurs, you
know all about the 8051 microcontroller and its variants.
The DS89C450 microcontroller does in one clock cycle what
the T-Rex 8051 does in 12 clock
cycles.
Remember the 8751? The 8751
had EPROM under quartz that could
be electrically programmed and
erased via a UV lamp. If you had a
few days between spins, you could
set your programmed 8751 in the
sunlight and eventually somewhat
erase the program memory area. I
used to keep opaque tabs to cover
the quartz window to prevent
accidental erasure of my 8751 code
that took days (and sometimes
weeks) to perfect. Not so with the
DS89C450 microcontroller. Like just
about every modern microcontroller,
the DS89C450 keeps your magic
potion safe in 32K of eight-bit Flash.
The DS89C450 doesn’t stray far
from the things that make it a true
128K x 8 SRAM
A0
A7
A6
A5
A1
A2
A4
A3
MEMOR Y ENABLE / I/O SELECT
0xF000-0xF1FF
0xF200-0xF3FF
0xF400-0xF5FF
0xF600-0xF7FF
0xF800-0xF9FF
0xFA00-0xFBFF
0xFC00-0xFDFF
0xFE00-0xFFFF