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 OverviewWireless, 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

ColorsViewing

AreaDot 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

Size Weight

2S-325085 Polymer Li-Ion Battery $19.95 7.4 V 1500 mAh 3.25" x 2" x .125" 2 oz.

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 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 mode1.433” 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 Modified Teko SM1.9

Casing composition Polystyrene

Color Black

Length 160 mm

Width 95 mm

Height 30 mm

Packaging Design

Packaging type Modified Teko SM1.9

Casing composition Polystyrene

Color 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