Transcript DesignReview

ECE 477 Design Review
Team 6  Spring 2006
Greg
Snow
Allan
Patterson
Kyle
McGhee
Joseph
Davidson
Outline
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
Wireless, Handheld TetriNET client
• TetriNET is an online variant of Tetris that allows a player to use “special
attacks” on himself or other opponents’ playing boards
• Device controls a local game of TetriNET
• Communicates with TetriNET servers via 802.11 to update opponent’s playing
boards and realize any special attacks
• Device provides the ability to view current battery level and recharge if
necessary
Screen shot shows the user’s playing board along
with the board of one other opponent (the opponents
boards can be rotated in to view every player in the
game)
Project Specific Success Criteria
1.
An ability to connect to TetriNET servers via 802.11b and
communicate with them using the TetriNET protocol.
2.
An ability to display game/status information on a graphics
LCD.
3.
An ability to control game action using a Directional-Pad
and pushbuttons.
4.
An ability to download and save (in non-volatile memory)
game configuration (e.g., game appearance and
preferences).
5.
An ability to display battery "fuel gauge" (on LCD) and
recharge battery when connected to an "A.C. adapter".
Block Diagram
Microcontroller Selection
Price
Flash
EEPROM
SRAM
I/O Pins
Max Freq.
VCC
Atmel ATmega2561
$17.09
256 KB
4 KB
8 KB
54
16 MHz
1.8-5.5 V
Atmel ATmega1281
$15.99
128 KB
4 KB
8 KB
54
16 MHz
1.8-5.5 V
Atmel ATmega2560
$17.97
256 KB
4 KB
8 KB
86
16 MHz
1.8-5.5 V
Considerations:
• Necessary I/O Pins: 47 (Compact Flash, LCD, Pushbuttons, Reprogramming
Circuit, Power Circuit)
• Larger Flash size provides memory to store any necessary libraries and color
schemes for game play
• 3.3V operating voltage matches all other components
LCD Screen Selection
Price
Number of
Dots
Colors
Viewing
Area
Dot Size
Back
Light
Controller
Hantronix HDM3224CL-S
$122.64
240 x 320
8
3.9"
234 μm x 68 μm
LED
Excluded
CrystalFontz
CFAG320240C-YMI-VZ LCD
$132.90
320 x 240
1
5.96"
340 μm x 340 μm
LED
Included
EarthLCD ezLCD-001
$149.00
240x160
512
2.7"
80 μm x 240 μm
LED
Included
Considerations:
• ezLCD includes built-in controller providing ability to issue drawing commands
instead of sending color data pixel by pixel
• ezLCD provides much deeper color depth, allowing up to 512 colors
• ezLCD provides necessary step up voltage circuitry to obtain voltages for
backlight
• ezLCD manufacturer provides free development kit for academic sales
Power Supply Selection
Price
Voltage
Current
Lifetime
2S-325085 Polymer Li-Ion Battery
$19.95
7.4 V
1500 mAh
35H10008-80 PDA T-Mobile Battery
$19.48
5.0 V
1000 mAh
HP 359113-001Li-Ion Battery
$25.00
3.6 V
3600 mAh
Size
Weight
3.25" x 2" x .125"
2 oz.
4.33" x 2.80" x .53"
3.899 oz.
Considerations:
• DC regulator’s required input voltage: 4.5 V
• Polymer Li-Ion battery provides a longer lifetime than the PDA battery (more
similar in cost & weight)
• HP Li-Ion battery would prove to be too large for our handheld device
• Polymer Li-Ion battery comes with a protection circuit to prevent over-charging
and over-discharging
Wireless Interface Selection
Price
Interface
Dimensions
DigiConnect Wi-ME
$275.00
Serial
.75” x .75 x 1.95”
Lantronix WiPort
$150.00
Serial
1.335” x 1.280” x 0.415”
DPAC Airborne WLNB-SE-DP101
$108.00
RS-232
1.60” x 1.17” x .46”
PRISM 2.5-based Compact Flash
$39.99
Compact Flash
8-bit mode
1.433” x 1.685” x .130”
Considerations:
• Compact Flash is the cheapest available option
• Compact Flash card dimensions are small enough to fit in a wireless device
• PRISM based drivers are very well documented
Packaging Design
Packaging type
Casing composition
Color
Modified Teko SM1.9
Polystyrene
Black
Length
160 mm
Width
95 mm
Height
30 mm
Packaging Design
Packaging type
Casing composition
Color
Modified Teko SM1.9
Polystyrene
Black
Length
160 mm
Width
95 mm
Height
30 mm
Microcontroller Circuit
• Central hub for almost all other components
• Primarily communicates with:
• Compact Flash
• Button MUX
• LCD Screen
• Reprogramming Circuit
• [Power Circuit]
Microcontroller Circuit - RP
• Reprogramming Circuit
• All pins attached to pins for alternate
functions
• JTAG interface
• ISP interface
• Reset pin
• SPI Clock Signal
• Essentially, these pins are just run into
headers which are used for debugging and
reprogramming
• A surface-mounted push-button used to
reset the system (only used for debugging)
Reprogramming Circuit
Microcontroller Circuit - BTN
• Button Circuit
• 10 Buttons
• Down, Left, Right, Up [Menu Navigation]
• Rotate Piece
• Use Item on Self, Use Item on Target
• Rotate Target Left, Rotate Target Right
• Pause / Quit
• Button signals fed into 5 2:1 MUX’s (PLD)
• Single select line from uC
• Button scanning performed by…
• Set select line low
• Check BTN_A0..4 for non-zero value
• Set select line high
• Check BTN_A0..4 for non-zero value
• Considering using an RC circuit attached to
each button to keep button signal active for
several milliseconds
Button Circuit
Microcontroller Circuit - CF
• Compact Flash [802.11 Wireless]
• 11 Address pins
• Compact Flash operating 8-bit mode
• Interfacing to a PRISM2 Chipset Wireless
Card
• Send commands to PRISM2 Chipset, and it
handles networking
• Implementing 802.11 with Microcontrollers
[book]
• Price & Size vs other wireless solutions
Wireless Compact Flash Circuit
Microcontroller Circuit – COM&LCD
• External Communication [Debugging]
• LCD
• External Communication signal sends
RS232 signals to header for debugging (from
microcontroller)
• LCD receives RS232 signals (can also input
USB, I2C, SPI & 8-bit parallel)
• ezLCD-001 inputs instruction signals
• For example…
• Draw “icon” at <x, y>
• Write text “east” (3 other directions
included)
• Change font
• All pins currently enter headers in case
future expansion is necessary
External Communication & LCD Circuit
Power Circuit
• Three primary components
• Battery Power reader
• Voltage regulator
• Battery Recharger
• System has two states
• “On” – no recharging capability
• “Off” – Rechargeable
• Battery Power reader
• Difference Amplifier
• (Vbat – Vcc) x Gain
• 3.3M / 5.6M (high impedence)
• Fed into ATD pin
• Voltage Regulator
• Regulates to 3.3V
• Recharging circuit
• Tested and known to work
• Diode prevents drain
• Battery has protection circuit
PCB Layout

Design Considerations:






ezLCD-001 must be in the middle of the PCB.
CompactFlash header must be at the top of the PCB.
Microcontroller placed on the back to lower the amount of vias
used.
Large width traces (40 mil) used for power and ground supplies
Ground primarily routed on the bottom of the board, power
primarily routed on the top.
Power circuit (whose components all use large amounts of
current) located in one corner of the board, away from the other
components, by the AC wall wart input.
PCB Layout – Full PCB
PCB Layout – Top Side
PCB Layout – Bottom Side
Software Design/Development Status
• Initial versions of “TetriSim” written
• Simulates LCD and button circuits
• Allows programming of game on computer
• Uses GLUT (open GL Utility Toolkit) to process graphics and inputs
• PRISM2 Driver
• Based on code by Fred Eady, Linux
• Implementing 802.11 with Microcontrollers
• Need to implement DHCP, 802.11 Site Survey
Project Completion Timeline
Current Status : 2/28 (Tuesday of Week 8)
• Completely Routed PCB Board
• All Parts in Hand
• Preliminary Software (TetriSim)
Project Completion Timeline
• Network Communication Software : 3/24 (Friday of Week 10)
• Local Tetris Software : 3/24 (Friday of Week 10)
• TetriNET Protocol : 3/31 (Friday of Week 11)
• User Interface / Battery Measurement Software : 3/31 (Friday of Week 11)
• Board Assembly / Complete Hardware Testing : 3/31 (Friday of Week 11)
• Complete Hardware / Software Debugging : 4/21 (Friday of Week 14)
Questions / Discussion