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ECE 477 Design Review
Team 13  Spring 2008
Paste a photo of team members here,
annotated with names of team members.
Srichand
Varun
Madhu
Anvesh
Outline
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Project overview
Project-specific success criteria
Block diagram
Component selection rationale
Packaging design
Schematic and theory of operation
PCB layout
Software design/development status
Project completion timeline
Questions / discussion
Project Overview
• An ordering system will be created where the
user will be able to order and pay for the
food from the comfort of the table
• Consists of a touch screen monitor which
displays the restaurant menu and allows the
user to select the items
• The order is sent through a wireless interface
which is received by the receiver
• The bill can be paid at the table using a RFID
gift card after it is validated
Project-Specific Success Criteria
• An ability to display information (menus, items
ordered, etc.) on an LCD.
• An ability to enter choices and select functions via
touch screen entry.
• An ability to read an RFID card and use decoded
user ID to look up personal account information.
• An ability to transmit menu choices over a wireless
interface (e.g., 802.15.4)
• An ability to customize the menu by getting data
from database.
Block Diagram
12 VDC
Supply
LCD Screen
(NEC 8.4”)
Touch Screen
Panel
4
2
Graphics Controller (Reach
Technologies
42-0105-01)
Voltage Regulator and
DC-DC Converters (5V to
3.3V)
2 SCI
2 GPIO
Microcontroller
(Freescale MC9S12C128)
1 SCI
RFID Reader
(Spark Fun ID – 12)
2 SCI
3 GPIO
ZigBee Transceiver
(Maxstream XBee Pro)
Component Selection Rationale
Wireless Transceiver
• Chosen component : Max stream XBee Pro
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1 SCI interface
Medium Range (300m Indoor)
Low power dissipation
Built in Antenna
• Competing Alternative : Atmel ATmega64RZAPV
Component Selection Rationale
RFID Reader
• Chosen component : Spark Fun ID-12 RFID Reader
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1 SCI Interface
Short Range (12 cm)
Low Cost
Built in Antenna
• Competing Alternative : Texas Instruments RI-STUMRD1
Component Selection Rationale
LCD and Touch Screen
• Chosen component : Reach Technologies 42-0105-01
LCD Touch Screen Kit
- Medium size (8.4” diagonally)
- External SD memory
- SCI Interface
• Competing Alternative : Apollo Display Technologies
T-51638D084J-FW-A-AB-V399B Touch screen LCD
Component Selection Rationale
Microcontroller
• Chosen component : MC9S12E128
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3 SCI Ports
80 pin packaging
25 MHz clock
Previously known microcontroller family and development
environment
• Competing Alternative : PIC dsPIC33FJ128MC706
Packaging Design
• Constraints
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Size and Durability
Portability
Heat Dissipation
Cost
Packaging Design
• Dimensions
- 226mm x 157mm x 47mm
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Material
- Non conducting material
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Screen Size
- 8.4 inch diagonally
Packaging Design
Packaging Design
Chosen Enclosure : PACTEC PT-10
External Dimensions: 7.9 x 11 x 3 in
Schematic (Microcontroller)
Schematic (Clock Generator)
• Colpitts
Oscillator setting
• Manufacturer’s
specifications
for capacitor and
resistor values
• 8 MHz Crystal
Schematic (ZigBee Wireless)
• DIN and DOUT are connected to the SCI
• RTS, CTS, Sleep and Reset are connected to the GPIOs
Schematic (Power Circuit)
• Non-synchronous
step down voltage
regulator
• For both 3.3 V and 5
V
• Very high efficiency
(up to 87%)
Schematic (Headers)
• Headers for RFID and Graphic Controller
• Pull-up resistors for RTS and TX of Graphic
Controller
• By-pass capacitor for the RFID header
PCB Layout
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Maximum Dimensions: 7.4 x 10.5 x 3 in
0807 SMD resistors and capacitors
2 Power supplies: 3.3 V and 5 V
Maximum Current Draw: 300 mA
Nets routed by priority
Status: All components placed
90 % routed
PCB Layout
Top Layer
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12 V – 60 mils
5 V – 60 mils
3.3 V – 30 mils
Others – 12 mils
PCB Layout
Bottom Layer
• GND – 60 mils
• Others – 12 mils
PCB Layout
Microcontroller
PCB Layout
Wireless Transceiver
PCB Layout
Power Supply Top
• All power supply kept
together
• 12 V input header placed
between the two circuits
PCB Layout
Power Supply Bottom
• GND header placed
between the two circuits
PCB Layout
Oscillator Circuit Top
• Colpitts Oscillator circuit
• 8 MHz crystal oscillator
PCB Layout
Oscillator Circuit Bottom
PCB Layout
RFID Header
• RX SCI pin
• 5 V and GND
• RESET tied to +5 V
PCB Layout
Graphic Controller Header
• GPIOs for RTS, Reset and GND
using 10k pull up
• TX using 10k pull up
• GND
Software Design
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Software is written in C using code warrior
Timer interrupt used to create system clock
All operations are contained in main loop
RFID and Touch screen works on interrupt
mode
Software Design
• Sequence of Operation
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Sleep mode
Interrupt on touch screen/RFID
Display Menu
Send order
Confirmation
Pay Bill
Sleep mode
Software Design
• Completed Interfaces :
- Tested RFID interface with 9S12C32
- System Clock
• Tasks to complete next :
- XBee Interface
- Graphical Interface
- Software code for customizing and Displaying
menu
Project Completion Timeline
Week
Finalize PCB
Populate PCB
Interfacing
Software Design
Packaging
Testing
Documentation
2/243/1
3/23/8
3/93/15
3/163/22
3/233/29
3/304/5
4/64/12
4/134/19
4/204/26
4/275/3
Questions / Discussion