Transcript Presentation Slides

Micro Processor
Project
ECE 300
April 17, 2004
Group 2
The Crew
Group 2:
Ross Chun
[email protected]
Andrew R. Geouque
[email protected]
Chin-Yu Hsu (Joe)
[email protected]
Procedure
1.
2.
3.
4.
5.
6.
Soldering the board
Testing the board for basic function
Sensor selection
Implementation of the sensor
Configuration of code necessary for
the selected sensor
Testing of the sensor
1. Soldering
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Soldering the components onto the
board was pretty straight forward
Took a little practice with the extra
board and the components
Hardest part was the microprocessor –
(had a hard time getting it aligned
properly)
2. Testing the Board
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Did not run into any problems. The
processor was flashed and programmed
correctly on the first attempt.
Some of the LCD pins had to be resoldered, but that was about we had to
do in order for the board to run the
“HELLO” program.
The Board
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This is a picture of the board
after all the soldering was
done.
The red input is tied to pin
P6.6/a6. The v_o of the sensor
will be tied to this input.
The black input is tied to an
arbitrary chosen ground on the
board. The ground pin of the
sensor will be tied to this
input.
The blue wire is tied to the
board’s VCC pin which will be
used as the sensor’s voltage
source.
3. Sensor Selection
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We wanted to use some kind of temperature sensor because
it seemed like it would be the most practical.
We looked at the temperature sensors suggested in the
project manual.
We also visited www.analog.com and did research on some
other temperature sensors.
In the end, the analog AD22103 temperature sensor was
chosen.
The AD22103
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Ratio-metric temperature
sensor
Sensor’s output voltage is
proportional to the power
supply voltage.
100 °C temperature span
(0 °C to + 100 °C )
Accuracy better that ± 2.5%
The Ad22103 cont.
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Because the sensor outputs a voltage that is
proportional to the temperature, the code
necessary to implement this sensor was
very simple.
It can be ordered either as an SO-8 (SOIC)
pin configuration or a TO-92 pin
configuration.
It was obvious to choose the TO-92 3 pin
design because it was much easier to make
connections with the board.
4. Implementation of the
Ad22103
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A small circuit board was purchased along with a
3 prong-plug to create a mounting base for the
sensor. Wires were also soldered to the board
for easy connections.
5. Configuration of the
Code
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The code that had to be written in order
for the Ad22103 to work was was very
simple.
Only a few lines of code had to be added
to the given sensor.c file.
Code Continued…
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After studying the data sheet and the given sensor.c file, we
realized that the majority of the work was already done for us.
The only thing that had to be done was create code that would
solve for the correct value of T_a and display the correct value
on the LCD.
V_out = (V_s/3.3 V) x [0.25 V + (28.0 mV/ °C ) x T_a]
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V_s = 2.86 V which was the voltage provided by the V_cc from
the board.
V_out = sample which is already a known value from the given
sensor.c file
More on the Code…
As you can see to the code
on your left, we declared
two new variables Cel and
Fah to denote the values of
temperature in both scales.
This was the code that
had to be implemented
to solve for the values
of Celsius and
Fahrenheit.
Extra Information on the
Code
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We realized that the refresh rate on of the board was quite slow
and we wanted to see if there is any way we could change the
rate so it would be a little faster.
We looked at and try to understand the delay.C and lcd.C files,
but we were unable to locate where the refresh rate was located.
The refresh rate is located in the sensor.C file and we thought that
all we had to do was change the value to something a little
smaller. However, this was not the case.
Some Info on #Define BT_ADLY
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Did a little google search and this is what we found.
There are only a set of certain values that can be used with this
definition.
6. Testing
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After some debugging and re-soldering of some lose pin
connections the sensor worked properly.
The refresh rate of 1000 ms seemed to be pretty good and
another version of code was created in order to display
temperature in Celcius and Fahrenheit.
Testing…
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Here is a picture of the working board and sensor.