University of Portland
School of Engineering
5000 N. Willamette Blvd.
Portland, OR 97203-5798
Phone 503 943 7314
Fax 503 943 7316
Functional Specifications
Team STEEL Bridge: A Digital
Thermostat
Contributors:
Shawn Patterson
Chris Wong
Kyle Woodard
Approvals
Name
√
Date
Dr. Albright
Name
Date
Dr. Nuxoll
Insert checkmark (√) next to name when approved.
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Revision History
Rev.
Date
Author
Reason for Changes
0.5
0.8
0.85
0.86
09/13/03
09/14/08
9/21/08
9/23/08
9/24/08
K. Woodard
K. Woodard
K. Woodard
K. Woodard
C. Wong
0.87
0.88
9/24/08
9/25/08
K. Woodard
S. Patterson
0.9
0.92
0.95
1.0
9/25/08
10/2/08
10/6/08
10/30/2008
All
K. Woodard
K. Woodard
K. Woodard
Wrote Background/Introduction
Wrote Requirements Section
Formatted Styles
Updated Background
Formatted Design, Development,
Conclusions, Appendices
Wrote Preliminary Design
Updated Milestones,
Assumptions and edited Intro,
Background
Finished Functional Spec
Revised Func Spec
Revised Func Spec
Made Industry Rep’s Changes
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Summary.......................................................................................................................
1
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FUNCTIONAL SPECIFICATIONS
Table of Contents
Introduction .................................................................................................................. 2
Background .................................................................................................................. 3
Requirements ............................................................................................................... 4
Overview ..................................................................................................................................................4
Physical Specifications............................................................................................................................5
Size ...................................................................................................................................................5
Display ..............................................................................................................................................5
Graphical User Interface ..................................................................................................................5
Environmental Specifications .................................................................................................................6
General .............................................................................................................................................6
Temperature .....................................................................................................................................6
Shock and Vibration .........................................................................................................................6
Hardware Specifications .........................................................................................................................6
System Hardware ............................................................................................................................6
Power Supply ............................................................................................................................7
Thermocouple ...........................................................................................................................7
Graphical User Interface ...........................................................................................................7
Display .......................................................................................................................................7
Buffers........................................................................................................................................7
Relay..........................................................................................................................................7
Amplifier .....................................................................................................................................7
Board Hardware ...............................................................................................................................8
MOSIS .......................................................................................................................................8
Software Specifications ...........................................................................................................................8
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B2Logic
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Preliminary. Design ...................................................................................................... 9
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Overview.of System Architecture ...........................................................................................................9
FUNCTIONAL SPECIFICATIONS
Component Details............................................................................................................................... 10
Thermostat Controller ................................................................................................................... 10
Relay System ................................................................................................................................ 11
LED Display and User Interface ................................................................................................... 12
Use Case .............................................................................................................................................. 12
User Sets Thermostat ................................................................................................................... 12
Development Process ...............................................................................................13
General Approach ................................................................................................................................ 13
Assumptions ......................................................................................................................................... 14
Milestones ............................................................................................................................................. 14
Risks ..................................................................................................................................................... 16
Faulty MOSIS Chip Fabrication.................................................................................................... 17
Analog-to-Digital Converter Malfunctions .................................................................................... 17
AFROTC Member’s Time Commitment Could Hinder Our Progress: ....................................... 17
Failing to Finish MOSIS Design by November 26, 2008: ........................................................... 17
Resources............................................................................................................................................. 18
Personnel....................................................................................................................................... 18
Preliminary Budget ........................................................................................................................ 18
Equipment ..................................................................................................................................... 18
Facilities ......................................................................................................................................... 19
Conclusions ...............................................................................................................20
Appendices.................................................................................................................21
Appendix A: 7-Segment Display.......................................................................................................... 21
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Appendix .B: Up/Down Counter ........................................................................................................... 22
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Figure 1. Block Diagram of Team STEEL Product.......................................................................................4
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Figure 2. Team STEEL System Architecture................................................................................................9
FUNCTIONAL SPECIFICATIONS
List of Figures
Figure 3. Block Diagram of Thermostat Controller (MOSIS Chip)............................................................ 10
Figure 4. Block Diagram of Relay System ................................................................................................. 11
Figure 5. Front View of LED Display and User Interface .......................................................................... 12
Figure 6. Seven Segment Decoder ............................................................................................................ 21
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Table 1. Physical Specifications ....................................................................................................................5
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Table 2. Environmental Specifications ..........................................................................................................6
FUNCTIONAL SPECIFICATIONS
List of Tables
Table 3. System Hardware Specifications ....................................................................................................6
Table 4. Board Hardware Specifications.......................................................................................................8
Table 5. Software Specifications ...................................................................................................................8
Table 6. Responsibilities and Time Management ..................................................................................... 13
Table 7. Team STEEL Milestones ............................................................................................................. 14
Table 8. Team STEEL's Risks.................................................................................................................... 16
Table 9. Team STEEL's Budget ................................................................................................................. 18
Table 10. Truth Table for LED Display ....................................................................................................... 21
Table 11. Next State Logic.......................................................................................................................... 22
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Summary
1
Team STEEL Bridge has designed a digital thermostat that will be installed in a
refrigerator. Our functional specifications document outlines the critical steps that went
into the planning of our project. Brainstorming all aspects of the project has benefitted our
team in numerous ways. A thorough design will minimize future headaches because we
are able to predict future problems. Considering all of the steps that will go into the final
product, decisions can be made now that will simplify our final product.
After the introduction and background, this document allowed us to predict all of the
physical requirements that would affect the design of our project. The requirements
section requires us to brainstorm physical, environmental, hardware and software
requirements. Thinking from a user’s perspective, we can address design problems
before they exist.
The preliminary design section is complete with block diagrams that specifically outline the
different sections of the digital thermostat. Broken into the following segments, the reader
can better understand the design of the project. These different segments consist of the
relay, user interface and display, and the thermostat controller. Connecting the thermostat
controller to the refrigerator’s compressor is a relay. The relay acts as a switch. The user
interface is simply up/down buttons that set the thermostat and the seven segment display
is mounted next to the user interface on top of the refrigerator.
Next is the design process, which outlines many important parts of our project. They
include assumptions, milestones, risks and resources. All of these are tools to aid in the
design of our project similar to the requirements section. The resource section ensures
that our design is within our budget. Risks are important to analyze as well because it is
another tool to predict problems that a user might face. If a risk is substantial, then we can
make design adjustments accordingly. The same applies to the assumptions section as
well. Milestones are used specifically for time management purposes and help keep us
on track.
Lastly, our document is ended with conclusion and appendices sections. The conclusion
addresses how our project plays into the importance of our college education because we
are able to pull all of our skills together to create a substantial project. The appendices
sections outlines equations, truth tables and other data that is important to understanding
our project.
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Introduction
2
The functional specification is aimed towards industrial representatives, University of
Portland faculty and fellow students wishing to obtain a thorough understanding of the
project created by Team STEEL Bridge. The goal of the senior capstone design project is
to apply our engineering education in a controlled, guided environment. This document
provides in detail how Team STEEL Bridge will accomplish its goals. If students wish to
expand our project in the future, they may use this document as a guideline and gain
valuable knowledge about how to avoid any errors that we encountered in the design and
test phases. However, just as valuable as this document will be to those reading it, it is
even more valuable to our team as we create it.
There are many tasks to accomplish to properly piece together the entire document.
These tasks include brainstorming specific requirements and obstacles that may be faced
in the construction of our project. For example, physical and environmental specifications
will be explained in great detail, as well as hardware and software requirements. By
explaining these specifications through this document, we are forced to limit the scope of
our design. This is important because an understanding of this scope forces the details of
many aspects of our design. Also, in the development process we are specifically
required to outline plausible risks. A description of the risk allows us to understand why it
is important to avoid it, and can help us prevent it from actually happening.. In addition,
we can determine the severity of the risk and create contingencies that we will take if the
risk were to occur. These risks could spark ideas and raise caution about our design that
may force us to change our plans. Identifying these problems benefits our team by
allowing us to improve the testing phase. By identifying possible obstacles, we can devise
tests that will improve our chance of success in senior design.
Another benefit to the functional specification is that we have to plan our overall progress
for our design in advance, which will directly improve our time-management skills. We are
able to identify all of the tasks necessary to finish the project and monitor our progress
closely. As we continue to work on the project we can manage our time by setting goals,
specifically to plan on finishing different tasks by certain dates. By identifying the specific
tasks we can be more productive by focusing our efforts on accomplishing them one at a
time. This is opposed to spending time on multiple tasks and making minimal progress. A
budget is also included to aid in our organization. Our design and overall scope of the
project is guided by the restrictions placed on our budget. Thus we are required to
brainstorm all costs and resources we must utilize in the completion of our project.
All aspects of our project are discussed in the functional specifications document except
for the progress that was made in finally deciding on a project. Our original idea went
through many changes before we settled on the refrigerator and this preliminary stage is
not included in this document. This document does, however, cover almost all aspects of
the project from its conception forward. Specifically, this document includes an
introduction with a summary and background; physical, environmental, hardware and
software requirements; preliminary design stages; development process including risks,
assumptions and the budget; conclusion and all necessary appendices.
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Background
3
The motivation for our project was the fact that modern refrigeration systems lack accurate
temperature control. Modern refrigerators are built with a turn dial setting for temperature,
where the range is an abstract “1-10” value. It is unclear what these values correspond to
in terms of actual temperature inside the refrigerator. Without such knowledge it is
impossible to know if our food is being kept at its optimal cooling temperature. Our
number one goal with this project is to deliver precise temperature measurements from a
refrigeration system to the user and even allow the user to select the exact temperature
they want their food at. We want to accomplish this goal by digitally displaying the
temperature of the contents of our refrigerator and creating a user interface where anyone
can digitally set their desired temperature.
Common refrigerators cannot set and gauge a specific temperature, but have a certain
range where the temperature can dwell in. Our goal is to improve the design of an
average refrigerator by reading and displaying an accurate reading, and being able to set
a desired temperature, which the system will never exceed.
Our project is centered on MOSIS technology. MOSIS is an industrially manufactured
integrated circuit that allows us to put all digital logic onto a high density programmable
chip. This programmable chip will house all of the low-level thermostat related digital
processing. Also, the chip will have user friendly in/out (I/O) features. These include
allowing a user to see the current temperature inside the refrigerator through several 7segment LED displays and letting a user set a desired temperature through the use of
up/down arrows corresponding to 1º F per push. Also, the chip will be able to electronically
drive a relay when needed, which will activate the refrigeration system. All outputs from
the MOSIS will be buffered and run through amplifiers in order to drive to the loads that
are attached to it.
Other technology that is used is a common seven segment display that is similar to one
that found on most digital clocks, a digital solid-state relay that runs the refrigerator’s
compressor, a user interface, a temperature probe that outputs a voltage corresponding to
the refrigerator’s temperature and an analog-to-digital converter to input that voltage into
the MOSIS.
Our project will be extremely marketable to anyone who would like to keep their food at its
optimal temperature. A thermostat is a simple concept accepted by all consumers
because they are all familiar with its workings. The user interface is simple and the digital
displays are convenient to read as well. The concept of a refrigerator is simple. Team
STEEL is simply enhancing its features.
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Requirements
4
Team STEEL is constructing a digital thermostat that will be installed into an existing
refrigerator that will be subjected to various physical requirements, but only a few will
hinder our design. The size of our refrigerator is large enough to not limit any of our
design specifications, except for the fact that most of the components must be inside of
the refrigerator. Near the compressor there is little room to mount our hardware and inside
the refrigerator our display and temperature sensor must not conflict with the refrigerator’s
functionality.
Hardware requirements will arise because the MOSIS will require buffers on all of the
outputs. Specifically, the MOSIS technology will rely on other components to drive the
different functions of the refrigerator. The software that writes to the MOSIS is restricted
and requires certain programming techniques to accommodate for the limited library.
Overview
Team STEEL is aiming to solve the persistent problem of consuming foods and
beverages that are not stored at a constant specified temperature. From outside the
refrigerator, consumers will be able to set a desired temperature and the correct
temperature will be displayed digitally as well; illustrated by the block diagram in figure 1.
Temperature
Sensing
Device
User Input/
Temp Display
MOSIS Thermostat
Controller
Refrigerator
Cooling System
Figure 1. Block Diagram of Team STEEL Product
Our system is centered on the MOSIS chip, located in the center of the diagram. This chip
houses all thermostat logic. The thermocouple module is a box designed to take in the
voltage from a thermocouple probe which will be located on the inside of our refrigerator.
The thermocouple probe is the connection of two different metals at one point which
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generates a voltage proportional to temperature. The thermocouple module will take in
this voltage, reference it to 0º F and convert it to a reading in milli-volts that corresponds
directly to the temperature. This voltage is then sent to an Analog-to-Digital Converter
(ADC) where it will be represented by a six-bit word. Once the MOSIS chip sees this data
it compares this temperature with the desired temperature set by the user. If the desired
temperature is less than the sensed temperature, the MOSIS sends a voltage to an output
connected to the refrigerator’s compressor. However, the MOSIS chip does not have the
driving capability for the compressor, so the output is run into a buffer which drives an
amplification stage before finally driving the compressor.
Physical Specifications
Table 1. Physical Specifications
Requirement
Value
Size
Display
Graphical User
Interface
Limited
Visible
Accessible
Size
The size of the refrigerator is already set because our project is centered on enhancing an
existing refrigerator. The size of our project comes within mounting our hardware inside
the compartment next to the compressor. Our product needs to be able to fit in a
refrigerator without causing spacing issues with its surroundings. The MOSIS chip and its
housing, the relay, current driving amplifier and thermocouple module are small enough
that we should not have any problems.
Display
Displaying the correct temperature must be done so that a consumer can read the
temperature from a fair distance in the home. This is why we did not use LCD, the LED
lights will display with ample brightness. They will also be displayed on top of the
refrigerator, vertically and on the front edge so that a consumer of any height can easily
view it.
Graphical User Interface
The buttons to set the temperature will be located next to the LED display. This will be
more convenient for our team because it will limit the amount of wire along the outside of
the refrigerator. Consumers will be able to reach the buttons because it will be on the front
of the refrigerator.
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Environmental Specifications
Table 2. Environmental Specifications
Requirement
Value
Temperature
Shock and Vibration
0°- 63°
Minimal
General
The refrigerator will only be subjected to use inside of the home. We will discourage any
consumer from using the product outside.
Temperature
All of our hardware will be protected from extreme cold or hot temperatures in the bottom
backside of the refrigerator. The only hardware that will be inside of the actual refrigerator
will be the temperature probe from the thermocouple. The temperature probe is a steel
wire that can withstand extreme temperatures that cannot be replicated in the
environments encountered by our project. The probe will only endure a temperature
between 0° and 63° Fahrenheit given our assumptions and having only six bits to work
with.
Shock and Vibration
Once the compressor turns on, there might be a little vibration that could disrupt the
MOSIS or relay after a long period of use. The vibration is subtle, so it will take a little
planning and repeated testing to ensure that our hardware can withstand the shock and
vibration.
Hardware Specifications
System Hardware
Table 3. System Hardware Specifications
Requirement
Value
Power Supply
Thermocouple
5 VDC
0-63
mVDC
TBD*
TBD
Buffers
Amplifier
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Relay
Display
Graphical User
Iinterface
PAGE 7
TBD
TBD
TBD
*To Be Determined
Power Supply
A power supply will tie into the power supplied into the compressor, which is supplied by
110 V. Regulating this voltage is yet to be determined so that we do not burn up the
MOSIS, but he MOSIS does requires a 5 volt DC input. and this will be regulated from the
power supply. The thermocouple requires a 9 volt battery to operate.
Thermocouple
Temperature will be sensed with a thermocouple that will be located with the rest of the
external hardware next to the compressor. It measures temperature by comparing a
difference from the temperature probe to a saved reference temperature. The output is a
voltage that is measured in milli-volts.
Graphical User Interface
Users will be able to directly set the desired temperature with two buttons that are
designated up or down. Each push will correspond to a one degree change. The set
temperature will be displayed on two 7-segment displays.
Display
Several seven segment LED arrays will be used to visually display the present and
desired temperatures.
Buffers
All outputs of the MOSIS will be sent to buffers that will prevent damage caused by current
entering the outputs. Plus, they will help drive the external components.
Relay
A solid-state transistor will be used to turn the compressor on and off. This will replace the
physical relay made up of two metal contacts that are controlled by a current created
through a coil to close the contacts. This allows the MOSIS to digitally control the
compressor and replace an electro-mechanical device which has less resilience to
repeated use.
Amplifier
The MOSIS chip does not have enough power on its own to drive the compressor, so
amplification is required prior to the compressor. This stage may require multiple stages
until the required amplification is reached. We will not know how much amplification is
required until we get our test refrigerator and determine its current draw. Once the current
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draw is determined, we will work backwards to find out how many amplification stages are
required.
Board Hardware
Table 4. Board Hardware Specifications
Requirement
Value
MOSIS
TBD
MOSIS
The convenience of using a MOSIS chip is that all logic is centered in one device. All
inputs from the graphical user interface (GUI) and thermocouple and outputs to the
compressor and display are tied straight to the MOSIS.
Software Specifications
Software Specifications contains a list of the software that will be required to run or support
the system.
Table 5. Software Specifications
Requirement Value
B2Logic.blt
L-edit
ABEL
TBD
TBD
TBD
B2Logic
B2Logic is the software that will be used to write our logic. This data can then be
converted to write our Complex Programmable Logic Device (CPLD) or MOSIS chip.
L-Edit
L-edit is a layout editing software used to get the .edf files from the B2Logic in order for the
MOSIS chip to be fabricated.
ABEL
Advanced Boolean Expression Language (ABEL) is a hardware description language
used to burn digital logic information onto a CPLD. It will be our backup circuit should our
MOSIS chip not function.
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Preliminary Design
Overview of System Architecture
Thermocouple
Module
User Input/
LED Display
Buffer
6-bit
Analog/Digital
Converter
MOSIS Chip
(Thermostat
Controller)
Buffer
Solid-State
Relay
Compressor
Figure 2. Team STEEL System Architecture
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The basic principles of our project are displayed in Figure 2. The thermocouple module is
a temperature probe and inputs temperature into the MOSIS. After reading the
temperature of the refrigerator from the display the user adjusts the temperature
accordingly with the buttons mounted next to the display. Using both of these inputs, the
MOSIS decides if the compressor needs to be activated. The component details’ section
outlines the specifics on how all of the functions are executed.
Component Details
Thermostat Controller
6-bits from A/D
Holding Register #1
To
LED
Display
Clock
Average
Holding Register #2
Set Temp
From User
Input
(6-bits)
Comparator
Output pin to
Compressor
(On if Set<Average)
Figure 3. Block Diagram of Thermostat Controller (MOSIS Chip)
The thermostat controller has two inputs. The first is from the ADC converter that receives
its input from the thermocouple. Temperature is read from the thermocouple and outputs
a voltage into the ADC converter. Voltage is then converted into a six bit binary number
that inputs into the first holding register in the MOSIS. Connected into the comparator is
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the temperature thermostat set directly from the user interface which consists of two
buttons, representing up and down arrows.
From the ADC converter the six bit binary number goes into the first holding register. At
the next rising edge of the clock, the binary number goes into the second register and the
first register acquires another reading from the ADC converter. Next, the two register
values are placed into the averaging segment, where they two binary numbers are added
and then shifted to the right in another register to signify dividing by two. Temperature
read from the thermocouple module will vary due to a slightly inconsistent temperature
inside the refrigerator. In order to avoid having the temperature reading in the 7-segment
display from flickering between different readings, Team STEEL has implemented the
averaging segment. This average is then sent to the LED display, to display an accurate
average reading of the temperature, and to the comparator.
Taking inputs from the averaging segment and the GUI, the comparator is then able to
determine if the set temperature is less than the actual temperature. If this is the case, a
voltage is outputted to the amplifier to turn on the refrigerator’s compressor.
Relay System
Output from MOSIS
Ic
Current
Amplifier
ICOMP
Power
Transistor
ICOM
P
Load:
Compressor
of
Refrigerator
Figure 4. Block Diagram of Relay System
If the user’s desired temperature is exceeded, digital information from the MOSIS chip
needs to be dispatched to the refrigerator’s solid-state relay system. The solid-state relay
turns on the compressor, which in turn, runs the cooling mechanism. The current draw will
be determined once we get our refrigerator. Hopefully there will be a nameplate that
specifies current draw of the compressor somewhere on the refrigerator. However, if we
cannot find a nameplate, we will use a current sensing device to determine the current
draw while the compressor is running. To get the current draw to the compressor, current
from the output of the MOSIS (IC) is sent through an amplifier, to reach the needed current
draw (ICOMP). Then ICOMP goes through a power transistor. The power transistor acts as a
switch. The transistor’s switch is open when cooling is not needed. When the desired
temperature is exceeded, cooling is needed and the amplified current activates the switch
to turn into a short. Then the needed current draw is sent to our load, which is the
compressor, and activates the cooling within the refrigerator.
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LED Display and User Interface
PRESENT
SET
UP
DOWN
Figure 5. Front View of LED Display and User Interface
We will group together an LED display and user interface together into a functional block
which will sit on top of the refrigerator. The LED display will consist of two sets of two 7segment displays. One set will display the present temperature inside the refrigerator as
sensed from the thermocouple module. The other set of 7-segment displays will show
what the user has set as his/her desired temperature for the refrigerator. The user
interface will consist of two pushbuttons; one for raising the desired temperature one
degree and the other for lowering the temperature one degree.
Use Case
User Sets Thermostat
Primary Actor: Average person who wants to keep food from spoiling.
Goal in context: Keep food at optimal temperature.
Preconditions: The user desires to keep food from spoiling or desires to get a better taste from food
that is colder.
Trigger: The user notices that food in his/her refrigerator is not cold enough
Scenarios: Probe senses temperature sending a corresponding voltage signal to the MOSIS in binary
form. MOSIS outputs signal to LED display. User toggles input buttons to a setting cooler than the
present temperature. Logic in the MOSIS activates the relay. The compressor turns on and removes
heat from the refrigerator. Temperature in the refrigerator is cooler than desired setting and cools food
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Exceptions: User prefers spoiled food.
Priority: Essential, must be implemented.
When Available: Whenever user wants to walk up and change settings.
Frequency of Use: As often as desired.
Channel to Primary Actor: Direct physical contact with pushbuttons.
Open Issues: None
Chapter
Development Process
6
General Approach
Here is a table depicting Team STEEL’s general approach through our design process.
Refer to the key below to see what each team member is working specifically.
Table 6. Responsibilities and Time Management
Shawn Patterson
Chris Wong
Kyle Woodard
Shawn Patterson
Chris Wong
Kyle Woodard
September
2
1
4,11
1,3
4,11
3
4
February
12
12
12
October
7
1
6
5
March
12
12
12
November
8,9,5
5
8,9,5
9,5
April
13
13
13
December
10,5
10,5
10,5
Key:
1= Design MOSIS Components in B^2Logic
2= Research Thermocouples
3= Research Refrigeration Systems
4= Functional Specifications
5= Theory of Operations
6= Combining MOSIS components and compiling .edf file
7= Get Refrigerator and test current draw
8= Finish Putting Together Full MOSIS design
9= Burn CPLD
10= Mount Hardware
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: CHRISTOPHER WONG
January
12,5
12,5
12,5
May
FUNCTIONAL SPECIFICATION
REV. 1.0
TEAM STEEL BRIDGE
PAGE 14
11= Order Parts
12= Test System, Debug
13= Prepare Presentation and Demonstration for Founder’s Day
Team STEEL’s approach to designing our system is to have two people focus on most of
the design and have the other person focus on documentation and overseeing the design
progress. We begin with doing some basic research about the peripherals surrounding
our MOSIS design. Next we need to design the MOSIS, one section at a time before
putting it all together in one final product. At the same time, we will collect all other
necessary hardware so that we and work with it as soon as the MOSIS design is
complete. Also, whenever certain documentation approaches a deadline the whole team
works to jointly get it completed on schedule and to make sure everyone is on the same
page for the overall design. Since we will have our MOSIS complete before winter break,
we will be able to use the entirety of second semester to put together and test our system
using a CPLD prior to the MOSIS chip arriving from fabrication. Once the chip arrives, we
will be able to insert it into our working system and already be prepare for Founder’s Day.
Assumptions
This section lists key events that characterize the environment. Here are some
assumptions:

Consumer only uses temperatures between the ranges of 0-63° Fahrenheit. We are
only using 6-bits to represent our temperature in binary. Food in a refrigerator should
not go below freezing, or exceed room temperature.

The refrigerator is going to use a solid-state relay. Older refrigerators have a different
type of relay system which involves a metal strips actuated by current flow. However,
newer and more modern refrigerators use a solid-state relay, so we assume our
thermostat will be used on the more modern refrigerators.

The refrigeration system using our product will be kept in a standard indoor
environment. We will not vouch for our product working after getting wet. Nor will we
vouch for it working in temperatures required by military standards.
Milestones
Table 7. Team STEEL Milestones
Number
Description
Original
10 Oct 08
Present
23 Sep 08
1
Pre-Approval Document
29 Aug 08
29 Aug 08
UNIVERSITY OF PORTLAND
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CONTACT: CHRISTOPHER WONG
FUNCTIONAL SPECIFICATION
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PAGE 15
2
Order Thermocouple
Module
17 Sep 08
17 Sep 08
3
Finish Higher Level Block
Diagram
17 Sep 08
17 Sep 08
4
Finish MOSIS Block
Diagram
17 Sep 08
17 Sep 08
5
Purchased Refrigerator
20 Sep 08
27 Sep 08
6
Program Review #1
23 Sep 08
23 Sep 08
7
Functional Spec 1.0
10 Oct 08
10 Oct 08
8
Program Review #2
28 Oct 08
28 Oct 08
9
MOSIS Specification
Complete
22 Nov 08
22 Nov 08
10
Burn CPLD
23 Nov 08
23 Nov 08
11
Theory of Operations 0.9
24 Nov 08
07 Dec 08
12
Program Review #3
02 Dec 08
02 Dec 08
13
Mount Hardware
03 Dec 08
03 Dec 08
14
TOps version 0.95
23 Jan 09
23 Jan 09
15
TOps version 1.0
30 Jan 09
30 Jan 09
16
Test Thermostat
5 Feb 09
5 Feb 09
17
Debug Thermostat
15 Feb 09
15 Feb 09
18
Put Together Display for
Founder’s Day
15 Mar 09
15 Mar 09
19
Presentation and
Demonstration for
Founder’s Day
07 Apr 09
07 Apr 09
Purchase Refrigerator
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FUNCTIONAL SPECIFICATION
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We purchased a test refrigerator in order to figure out the way modern refrigerators work
and to test compatibility with MOSIS outputs. Currently, we have a good idea of how a
modern refrigerator works to keep the contents cool. However, we have never actually
worked with one before. Therefore, we need to be able to experiment with a test
refrigerator to get a feel for how the current system works and what we can do to improve
it with a MOSIS chip. Also, we need to make sure that we figure out how much current
draw is required by a modern refrigeration system. This will determine how much
amplification is required after the output of the MOSIS chip.
MOSIS Specification Complete
It is imperative that we finish the design of our MOSIS chip by this date. On this date, Dr.
PeterOsterberg needs to send our finished design off to the MOSIS fabricators so that it
will be built and returned to us by the time we need to present our project.
Burn CPLD
Instead of waiting for our MOSIS chip to return from fabrication, we have the ability to burn
our same chip design onto a CPLD. This allows our team to test our design even though
our chip still has not come back. Thus, we have more time to test and debug our design.
Also, if for some reason the MOSIS comes back ineffective, we already will have a
working chip. We want to get the CPLD done as early as possible, which is why the date
we set for its burning is the day after required submission of our final design. Getting the
CPLD ready early will allow even more time for debugging our design and will aid us in
getting ahead of schedule for the second semester.
Mount Hardware
Mounting all our hardware entails installing all additional devices on our refrigerator. A
user display and input will be installed as well as a thermocouple module, CPLD, buffer
between our CPLD and cooling system, and a solid-state relay, which drives the cooling
system. Just as with the CPLD, we want to get this step done as soon as possible, which
for us is early December. This will allow us to begin testing our finished design
immediately. As a result, we will be able to finish our testing even before our MOSIS chip
arrives. And as soon as the chip does arrive, all we will have to do is install it and we will
have a finished product.
Risks
Table 8. Team STEEL's Risks
Risk
Severity
Likelihood
Faulty MOSIS Chip Fabrication
Low
Low
Analog-to-Digital Converter Malfunctions
Moderate
Moderate
UNIVERSITY OF PORTLAND
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AFROTC Member’s Time Commitment Could Hinder our Progress
Moderate
High
Failing to Finish MOSIS Design by November 26, 2008:
High
Low
Faulty MOSIS Chip Fabrication
Once turning in the final schematics before the November 26th deadline, Dr. Osterberg
sends our chip to be fabricated and created. There might be a chance that even if our
logic was correct, the fabrication company can mess up our chip, or the chip will not work
altogether.
If it fails, a CPLD needs to be made before sending the MOSIS chip to fabrication. The
CPLD can take the place of a MOSIS. CPLDs hold less digital information, but if there is a
lot of data to read, multiple CPLDs can be made to take the place of one MOSIS.
Analog-to-Digital Converter Malfunctions
The analog-to-digital (ADC) converter is a main component in our project because it sends
the information given by the thermocouple digitally to the MOSIS chip. If the converter or
our team cannot match the output of the ADC converter to the input of the MOSIS, the
project cannot be completed.
To avoid troubles with our converter, a lot of research needs to be focused on what ADC
converter is the most suitable for our project. Research can be done by looking online or
by asking specialists, like our professors or Craig Henry, University of Portland’s electronic
technician about which converter to purchase.
AFROTC Member’s Time Commitment Could Hinder Our Progress:
Kyle Woodard is a cadet in the Air Force ROTC at this university. Having additional
responsibilities can slow the process of this project.
To remedy this, most of the digital logic (the core of the project) will be left to the other
members of Team STEEL Bridge, and Kyle will focus more on the writing and journalistic
areas of the project. Time management will be crucial, too.
Failing to Finish MOSIS Design by November 26, 2008:
All digital logic has to be finished, processed and put into our MOSIS chip design by
November 26, 2008. This deadline was put in effect by Dr. Peter Osterberg for all projects
that incorporate MOSIS technology. If our group fails to accomplish this, our project will be
compromised because it is the core of this project. However, if late, a CPLD can be made
to take its place.
Due to the simplicity of the MOSIS, it is to our benefit to finish the digital aspect on time. In
addition, finishing on time will allow each of us to enjoy our winter break without having to
do on our project.
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: CHRISTOPHER WONG
FUNCTIONAL SPECIFICATION
REV. 1.0
TEAM STEEL BRIDGE
PAGE 18
To avoid this situation, a block diagram of the important sections of the MOSIS will be
made immediately. Then each section will be created efficiently on an individual basis.
Then after all the parts are designed, each piece will be attached or bussed together as
needed.
Resources
Personnel
Below shows who is working on the project and their general or specific role.

Christopher Wong. Team leader for Fall Semester. His main role is to configure the
digital logic and create the central MOSIS chip.

Shawn Patterson. Team leader for Spring Semester.
necessary parts and help create the MOSIS chip.

Kyle Woodard. His main responsibilities are to uphold and maintain documents and
our team’s website.

Dr. Robert Albright. He is our primary advisor, and every week he is involved with our
group’s team meetings, providing valuable insight and advise.

Dr. Peter Osterberg. He is our secondary advisor, and he looks over the well-being of
the MOSIS design. He is the specialist in MOSIS technology, and whenever there is
a problem with MOSIS, we will turn to him for help. He is also responsible for
sending the chip off for fabrication after the internal logic is completely designed.
His main role is to order
Preliminary Budget
Table 9. Team STEEL's Budget
Line
1.1
1.2
1.3
1.4
1.5
Category
Hardware
Hardware
Hardware
Hardware
Materials
Description
0.3-Inch, 7-Segment LED Display
80TK Thermocouple Module
Analog-to-Digital Converter
Current Amplifier
Miscellaneous
# of Parts
10
1
1
1
1
TOTAL
Rate
$2.93/10 LEDs
$92.24
$3.64
$6.96
$30.00
Amount
$2.93
$92.24
$3.64
$6.96
$30.00
$135,77
Equipment
Special equipment, or outside equipment that needs to be used is a digital multi-meter
(DMM) to test the output voltage of the thermocouple.
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: CHRISTOPHER WONG
FUNCTIONAL SPECIFICATION
REV. 1.0
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PAGE 19
Facilities
For testing hardware, we are using laboratory space in Engineering Hall 2001.
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FUNCTIONAL SPECIFICATION
Chapter
REV. 1.0
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Conclusions
7
In summary, our team is creating a digital thermostat that will read, set, compare and
display the real and user-desired temperatures for a refrigerator, so the consumer can
enjoy their cold food and beverages at their liking.
MOSIS technology is the core element of this project because all deadlines, digital logic,
and completion of this project depend on the completion of this integrated chip. The
MOSIS chip will hold all digital logic that will allow us to read the measured temperature,
allow the user to set the temperature, compare the set and measured temperatures, and
send that information to the refrigerator’s relay system and our to LED temperature
display. Because the MOSIS needs to be fabricated, all circuit diagrams and files needed
to create this programmable chip need to be done before November 26, 2008 when our
secondary advisor, Dr. Peter Osterberg, submits it for fabrication. Forcing our team to
compete the MOSIS by an early date motivates, encourages and forces us to have our
project, as an entirety, almost complete by Winter Break.
Outside MOSIS technology, our team will be using an 80TK Thermocouple by Fluke to
sense the temperature inside the refrigerator. That thermocouple will output a voltage,
and that voltage will represent a temperature in degrees Fahrenheit, and in turn will be put
through an analog-to-digital converter so the number can be represented digitally to our
MOSIS chip.
Our report shows the steps that is required to make this in great detail, a thorough
preliminary design, risks, consumer requirements, and what is necessary both in industry
and practice to complete our task.
For consumers, this product will be a necessity for cooling foods. For our team, we hope
that this project will be another milestone in our quests to becoming efficient and adept
electrical engineers. This project will teach us about the industry, teamwork, the
extraneous amount of documentation and skills needed to excel once we graduate.
Hopefully with the completion of our digital thermostat, we can reach and surpass this
goal.
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: CHRISTOPHER WONG
FUNCTIONAL SPECIFICATION
REV. 1.0
TEAM STEEL BRIDGE
PAGE 21
Appendices
Appendix A: 7-Segment Display
Figure 6. Seven Segment Decoder
Table 10. Truth Table for LED Display
Decimal
0
1
2
3
4
5
6
7
8
9
F
UNIVERSITY OF PORTLAND
4-Bit Binary
ABCD
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
n/a
B0
B1
B2
B3
B4
B5
B6
1
0
1
1
0
1
1
1
1
1
Vs
1
1
1
1
1
0
0
1
1
1
GND
1
1
0
1
1
1
1
1
1
1
GND
1
0
1
1
0
1
1
0
1
1
GND
1
0
1
0
0
0
1
0
1
0
Vs
1
0
0
0
1
1
1
0
1
1
Vs
0
0
1
1
1
1
1
0
1
1
Vs
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Appendix B: Up/Down Counter
Table 11. Next State Logic
Decimal
0
1
2
3
4
5
6
7
8
9
Current State:
ABCD
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
Next State: UP
AUBUCUDU
0001
0010
0011
0100
0101
0110
0111
1000
1001
0000
Carryover:
Up
0
0
0
0
0
0
0
0
0
1
Next State: DOWN
ADBDCDDD
1001
0000
0001
0010
0011
0100
0101
0110
0111
1000
Carryover:
Down
1
0
0
0
0
0
0
0
0
0
Truth Table and Next-State Equations for Up/Down Counter with Carryover Bit(s):
AU = AB + BCD
BU = BC’ + BD’ + B’CD
CU = CD’ + A’C’D
DU = D’
Carryover UP = AD
AD = A’B’C’D’ + AD
BD = AD’ + BD + BC
CD = CD + BC’D’ + AC’D’
DD = D’
Carryover DOWN = A’B’C’D’
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