>>>READER-TO-READER QUESTIONS AND ANSWERS
#4075 Orval Hollingsworth
Can anyone recommend a decent
electronics glossary of terms or
I am new to programming and
need some advice on which assembly
code is better to start out on. What
book (or books) should I get?
#1 If you’re new to programming,
there are two types of programming
to choose from. The first is procedural
(which includes assembly); the
second is object orientated. Object
Orientated Programming (OOP) can
easily be learned by downloading
Express Editions of Visual Studio (for
free) from Microsoft; along with
numerous code samples and support
information (from MSDN, also free);
there are a lot of beginning programming books available for this platform.
OOP has the advantage that it is the
standard for corporate development.
The primary reason to learn
assembly is for speed and absolute
access to the physical hardware. If you
don’t need both of these, learning a
language like C might work out better
for you. C is almost as fast as assembly
and has the advantage that you
can use it across various platforms.
There are a lot of very good books for
beginners for it, as well.
If you’re still set on learning
assembly; the first thing you need to
pick is your processor. Unless you
already have a platform in mind, I
would suggest picking one of these
three: Microchip PIC microcontrollers;
Atmel ARM microcontrollers; and TI
My personal recommendation is
the TI product; the development environment is only $20, which includes a
USB programmer, Flash-based processor board, and all the development
software. In addition, the assembly
language itself is very robust and easy
to understand, and the kit includes a
wealth of code examples. Once
you’ve learned one assembly
language, learning a second is much
easier since you only have to learn
how the mnemonics are different.
If this is just for fun, then I would
suggest getting an Apple II+ emulator
off the Internet (like Apple Win) and a
6502 assembly language tutor book
from Amazon. These books are very
education focused, plus, you can play
classic Apple games while learning.
Ladera Ranch, CA
#2 You didn't mention which particular processor or microcontroller
for which you would like to learn
assembly. I will assume that you would
be interested in the PIC microcontrollers manufactured by Microchip.
The first resource you will want to
consider is the manufacturer's website, www.microchip.com. Here, you
will find a wealth of knowledge in the
form of reference manuals, device
datasheets, and application notes.
Also, be sure to download the MPLAB
Integrated Development Environment.
This free software package includes a
simulator which allows you to single-step through each line of code and
examine the results. This can be a very
valuable tool in understanding how a
particular microcontroller works.
Myke Predko has written an in-depth book (nearly 1,200 pages) entitled "Programming and Customizing
PICmicro Microcontrollers." This book
starts with the basics and provides
[#1073 - January 2007]
I have an antique tractor that has a 6 VDC electrical system. Because this tractor is not used like the daily workhorse
it once was, I have to charge the battery every month or so.
I can find 12 VDC float chargers; and, in fact, use these $15
gems to maintain most of my lead-acid batteries. Can you
provide me a circuit that will maintain the voltage of 6 VDC
lead-acid batteries? The circuit would stay plugged into the
110 VAC mains and monitor the battery voltage.
#1 I have an Enerwatt 612-900 that would do what you
ask. It looks like a larger-than-normal wall-wart, and comes
with clamps and ring terminals.
It charges 6 or 12 volt lead-acid batteries with three
stage charging and is designed to be left on the battery
I paid about $35 (Canadian) for it, and it’s available
from Prairie Battery ( www.prairiebattery.ca).
#2 I have not built this, but I carefully checked the
ratings. The fuse is 5 X 20 mm and is to be mounted on perf
board using two fuse clips. I chose 315 mA because it is a
size used in meters and is readily available. The transformer
94 April 2007
has wire leads and can be bolted to the chassis or perf
board. The parts were chosen to be able to be mounted on
perf board or a RadioShack project board. The red LED is
just to show that power is on.
The circuit in Figure 1 operates this way: R2 and D1,
D2 limit the current through the TIP41 to about one amp.
It would take a week to charge a dead battery with this
circuit, so it is not a fast charger, but when the battery is
charged, it will maintain it. When the battery voltage rises
to 6. 8 volts, the PN2222 is turned on, which lights the
green LED and shuts down the TIP41. The circuit will
Q TY PART MOUSER PART #
2 FUSE HOLDER 441-EPD203P
1 FUSE 5x20 MM 504-GDB-315MA
1 XFMR 41FG010
1 BRIDGE 627-S1VB20-7000
1 R6 1/4W 291-470-RC
1 R1 1/2W 293-56-RC
1 TIP41 511-TIP41CN
1 R2 1/2W 293-0.5-RC
2 D1, D2 78-1N4148
QT Y PART MOUSER PART #
1 PN2222 512-PN2222TA
1 GRN LED 604-WP7104SGD
1 RED LED 604-WP63SRD
1 R3 1/4W 291-270-RC
1 R4 1/4W 291-240-RC
1 100 OHM POT 652-3352E-1-101LF