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including relative vs. absolute, two sensors,
binary vs. grey code, single-track codes,
v-scan, u-scan.
Optional related links:
Details on a particular relative encoder
Wikipedia article: "Rotary encoder"
Detail of a 13-bit grey code absolute encoder.
(Click on the "launch" tab, then "Motor
Principles" and then use the navigation
buttons provided on the bottom of each page.)
A few caveats about the above tutorial. . .
In the illustration of the "Switched Rluctance"
motor, the rotor will assume an induced
magnetic field to oppose the applied magnetic
field. This is not illustrated, probably
because it might imply that the rotor is
permanently magnetized, which it is not. It is
just iron (or a steel alloy).
In the illustration of the "AC Induction Motor"
the coloration of the induced magnetic field
in the rotor is backwards. According to Lens'
Law, the induced field will oppose the applied
magnetic feild from the stator. Thus the red
(north) pole of the stator will face a green
(south) pole on the rotor, just as in any other
motor.
Also read this motor tutorial and
optionally this control tutorial from
"Process Automation Control." Much of what is
described in the control tutorial can now be
done with microcontrollers.
There will be no problem set this week.
datasheet. Note that the Arduino uses the
"328P" microcontroller.
Note, the above link only works on computers that have
a connection to the Dordt College network and have
the F: drive mounted. It also does not work in some
browsers. If it does not work for you then download
it directly from Atmel but this will be slower.
Note errata in Ch. 7 on page 21. Register EEARH
should show bit 9 as "EEAR9" (not "–"). This
is a read/write bit, "R/W" (not "R") which
returns the stored data, "X" or "–", (not "0").
A corrected illustration is shown here.
Do these problems on uC memory systems
Overview of Arduino interrupt programming,
Optional: Smiley's Workshop Part 8 for a more
detailed and more typical approach to
programming interrupts in the C language.
(The Smiley's Workshop link only works after you have
logged into courses@ dordt.) Code supplements for
the Smiley's article are available on the web in a zip file.)
Optional: De Boer's notes on interrupts
Do these problems on interrupts
Errata: On problem 3.17 part (d) note that the
only way for Tpi to be an average and a mazimum
at the same time is that the ISR takes exactly
Tpi to execute every time it runs. This was the
author's intent. (As opposed to allowing
actual execution times to sometimes exceed Tpi.)
Note: On Monday, 3/25 the due date was extended from
Tuesday, 3/26, to Thursday, 3/28.
(This copy might print better on your printer.)
Scan over these application notes from Texas
Instruments on transmission lines. Read
The section in AN-807 on the "tabular method."
AN-806, and AN-807, and AN-808.
Do 2.1 and 2.6 in the handout linked above.
Optional: TI has purchased National Semi
The application notes linked above were
origianlly developed by National Semiconductor.
There is more on National Semi in Wikipedia.
in the library (It is on reserve. Ask a librarian
for it by name, "Universal Serial Bus") or
available from USB.org. If you download it
from USB.org be sure to read the 2.0 version.
(The 2.0 version superceeds the 1.0 version
which is now withdrawn. However the 3.0 version
is an addendum to the 2.0 version. It cannot
stand on its own.)
Do these short essays on USB.
Optional: You may turn the assignment in
electronically via courses@dordt.
Optional Reading: USB article in Wikipedia
Take this twenty-question quiz.
E-mail your quiz grade to Prof. De Boer.
You are encouraged to repeat the quiz until
you get a perfect grade. Turn in only your
best grade.
Optional: Books in Dordt's Library
Optional: Wikipedia article Ethernet
Do this problem:
Plot voltage vs. time of the Tx line in RS-232
for sending this text: "Z#" (without the
quotation marks, with a capital "Z"). Assume
±12 V signal voltages, 53 kbaud, eight data
bits, and one stop bit. Be sure to label your
axes properly. An ASCII table can be found in
many places, e.g. http://www.asciitable.com
Note that the illustration in the Wikipedia
reading does not have properly labeled axes.
Specifically the the independent axis lacks
scale and units.
Optional: Listen to a Teletype machine.
And see a Teletype machine connected to a
Digital Equipment Corporation (DEC, a brand)
model PDP-8/e computer. This computer could be
booted "manually" via a bank of switches that
allows the direct entry of machine code word-by
word, executing each instruction as fast as the
operator can enter the code. Wow, that's fast!
Optional: Read about teleprinters.
Optional: The entire RS-232 standard is
available from Dordt's library. Interface
Between Data Terminal Equipment And Data
Circuit-Terminating Equipment Employing Serial
Binary Data Interchange TK7887.5 .I57 1997
Modify this H-bridge circuit to so that the
two bits of input to the driver are D for
direction and E for energize. These will
replace the existing inputs W1 and W2.
If E = 1 then the motor should be powered.
If E = 0 then the motor should freewheel.
The uC may then use pulse-width modulation on
E to control the motor's speed.
Hints: All the resistors and transistors will
remain interconnected exactly as shown in the
given schematic. The changes pertain to the
intput signals and the logic gates.
As given in Figure 1.A. . .
A logic-1 at pin 1 of U3 will turn Q1 and Q5 on.
A logic-1 at pin 8 of U1 will turn Q2 on and Q6 off.
A logic-1 at pin 4 of U3 will turn Q3 and Q7 on.
A logic-1 at pin 11 of U1 will turn Q4 on and Q8 off.
The rectangles are European style symbols for
resistors. The value "3k8" is equivalent to
"3.8 kΩ."
Browse "Getting Started with Arduino"
Browse this datasheet.
Do the introductory problems
Note the chip number of the uC on the Arduino
Uno is "ATMEGA328P-PV."
Turn this problem set in electronically via
courses@dordt. (Maximum file size is 1 MB)