ECE 477 Design Review ECE 477 Design Review Team 14 Team 14 Spring 2006 Spring 2006

Jason, Nathanael, David, DavidJason, Nathanael, David, David

Project OverviewProject Overview

• Driver interface for Solar Racing TeamDriver interface for Solar Racing Team• Communication with onboard power trackers Communication with onboard power trackers

and telemetry board via CAN busand telemetry board via CAN bus• Display speed, battery power, and other Display speed, battery power, and other

information on the LCD information on the LCD • Allow driver to navigate through a text-based Allow driver to navigate through a text-based

interface to customize display information interface to customize display information and issue commands to the power trackersand issue commands to the power trackers

Project-Specific Success CriteriaProject-Specific Success Criteria

• An ability to display vehicle status information on an An ability to display vehicle status information on an LCD.LCD.

• An ability to navigate display menus and make An ability to navigate display menus and make selections using an RPG.selections using an RPG.

• An ability to perform LCD backlight power An ability to perform LCD backlight power management (e.g., turn the backlight on for X management (e.g., turn the backlight on for X seconds after the RPG is turned/pressed).seconds after the RPG is turned/pressed).

• An ability to obtain vehicle diagnostic information An ability to obtain vehicle diagnostic information via the CAN bus.via the CAN bus.

• An ability to switch to “debug” mode (when a RS-232 An ability to switch to “debug” mode (when a RS-232 cable is connected) in which a diagnostic menu is cable is connected) in which a diagnostic menu is displayed.displayed.

Block DiagramBlock Diagram

MicrocontrollerPIC18F4680

Debug CableDetect

CAN CableDetect

Light Sensor

Temp Sensor

5V Sensor

Watch Dog LED

2 LEDs

RS232Transciever

CANTransciever

9 Pin D-Sub

6 Pin MTE X 2

Cable HarnessConnector

LCD Header

RPG pushbutton

Return pushbutton

Spare pushbutton

Reset button

DC-DCConverter

LTC1174-5

Power LED

Buzzer

RPG

5V out

12VDCin

2(GIO)

1(GIO)

1

2(CAN)

2(RS232)

2

2

2(GIO)

3(GIO)

2

2

2

2

2(GIO)

1(AD)

1(AD)

1(AD)

1(GIO)

1(GIO)

2(GIO) Input

Output

Processor

Power

RS232

CAN

LEGEND

Professional ComponentsProfessional Components

• Constraint analysis and component selection Constraint analysis and component selection rationalerationale

• Patent liability analysisPatent liability analysis• Reliability and safety analysisReliability and safety analysis• Ethical and environmental impact analysisEthical and environmental impact analysis

Constraint AnalysisConstraint Analysis

Component Selection RationaleComponent Selection Rationale

• Design constraintsDesign constraints– MicrocontrollerMicrocontroller

• PIC18 familyPIC18 family• Support CAN standardSupport CAN standard• Large Flash & SRAM (CANopen library)Large Flash & SRAM (CANopen library)• 29 I/O Pins29 I/O Pins

– Power supplyPower supply• Step down from 12 VDC to 5 VDCStep down from 12 VDC to 5 VDC• 400mA @ 12 VDC input current limit400mA @ 12 VDC input current limit• High efficiency to reduce power-loss High efficiency to reduce power-loss

Component Selection RationaleComponent Selection Rationale

• Microcontroller Microcontroller

(PIC18F series with CAN, I2C, UART, PWM)(PIC18F series with CAN, I2C, UART, PWM)– PIC18F4680 (44pin TQFP) Cost: $6.08 ***PIC18F4680 (44pin TQFP) Cost: $6.08 ***

• 64Kb Flash64Kb Flash• 36 I/O36 I/O

– PIC18F2680 (28pin SOIC) Cost: $5.54PIC18F2680 (28pin SOIC) Cost: $5.54• 25 I/O (not quite enough need 29)25 I/O (not quite enough need 29)• Could use larger/different PLD to expand I/O, Could use larger/different PLD to expand I/O,

but PLD cost increase is greater than $0.54but PLD cost increase is greater than $0.54

Component Selection RationaleComponent Selection Rationale

• Power Supply (~400mA @ 5VDC)Power Supply (~400mA @ 5VDC)– MAX744AMAX744A

• 750mA output at 5VDC750mA output at 5VDC• 6 external components6 external components• ~88% efficient, 400mA @ 5VDC~88% efficient, 400mA @ 5VDC• Needs special layout with copper poursNeeds special layout with copper pours

– LTC1174-5 ***LTC1174-5 ***• 640mA output at 5VDC640mA output at 5VDC• 6 external components6 external components• ~90% efficient, 400mA @ 5VDC~90% efficient, 400mA @ 5VDC• Recommended in class documentationRecommended in class documentation

Patent Liability AnalysisPatent Liability Analysis

• OverviewOverview– Three Patent were found to be similar Three Patent were found to be similar – Literal infringement Literal infringement – Infringement under doctrine of equivalent Infringement under doctrine of equivalent – Action Recommended Action Recommended

Search Result #1Search Result #1

• Information display system for a vehicleInformation display system for a vehicle• Patent Number : 5,006,829Patent Number : 5,006,829• Assignee: Honda. Giken Kogyo K.K.Assignee: Honda. Giken Kogyo K.K.• Year: 1988Year: 1988• Description: Description:

»Sensors Sensors »A pair of buttons are used for A pair of buttons are used for

sequentially shifting the menu itemsequentially shifting the menu item»After a certain time interval, go to idle After a certain time interval, go to idle

mode mode

Search Result #2Search Result #2

• Display apparatus for vehicleDisplay apparatus for vehicle• Patent Number : 5,121,112Patent Number : 5,121,112• Assignee: Nissan Motor CompanyAssignee: Nissan Motor Company• Year: 1989Year: 1989• Description: Description:

»Sensors Sensors »Message is assigned a degree of Message is assigned a degree of

priority levelpriority level» Indicator for alert message Indicator for alert message

Search Result #3Search Result #3

• Information display appatatus for vehicleInformation display appatatus for vehicle• Patent Number : 5,764,139Patent Number : 5,764,139• Assignee: Toyota Jidosha Kabushiki KaishaAssignee: Toyota Jidosha Kabushiki Kaisha• Year: 1996Year: 1996• Description: Description:

»Sensors, detecting running condition Sensors, detecting running condition »Status are stored in local memoryStatus are stored in local memory»Size of Speed increase when vehicle Size of Speed increase when vehicle

is going straight is going straight

Literal infringementLiteral infringement

• Violating Condition Violating Condition • Ever claim must matchEver claim must match• Potential infringement PatentPotential infringement Patent

– Information display system for a vehicleInformation display system for a vehicle

Infringement under doctrine of Infringement under doctrine of equivalentequivalent• Not as trivial to be identified Not as trivial to be identified • To determine what function is substantially To determine what function is substantially

the same the same • To locate the differences To locate the differences

Action RecommendedAction Recommended

Reliability/Safety AnalysisReliability/Safety Analysis

Ethical/Environmental AnalysisEthical/Environmental Analysis

Ethical/Environmental AnalysisEthical/Environmental Analysis

• Ethical AnalysisEthical Analysis

– Focus on the safety of the driver from Hardware, Focus on the safety of the driver from Hardware, Software, and System Perspectives.Software, and System Perspectives.

• HardwareHardware

– High Efficiency DC/DC converter was chosen for High Efficiency DC/DC converter was chosen for its high efficiency and short circuit protection.its high efficiency and short circuit protection.

– Optical Isolators was installed to protect the Optical Isolators was installed to protect the microcontroller and LCD from Damage.microcontroller and LCD from Damage.

– PCB was carefully designed to avoid overheating PCB was carefully designed to avoid overheating and short circuit problems. and short circuit problems.

Ethical/Environmental AnalysisEthical/Environmental Analysis

• SoftwareSoftware

– Setting the CAN communication interrupts at the Setting the CAN communication interrupts at the highest priority to display the most accurate and highest priority to display the most accurate and timely information.timely information.

• SystemSystem

– Surface mount components were used on PCBSurface mount components were used on PCB– Connectors have board-retention devices.Connectors have board-retention devices.– LCD and PCB were tightly mounted in a plastic LCD and PCB were tightly mounted in a plastic

enclosure.enclosure.

Ethical/Environmental AnalysisEthical/Environmental Analysis

• Environmental AnalysisEnvironmental Analysis

– Product ManufactureProduct Manufacture

• Plastic enclosures made of non-biodegradable Plastic enclosures made of non-biodegradable plastic plastic

• Numbers of hazardous by-products are Numbers of hazardous by-products are produced during the PCB manufacturing cycle. produced during the PCB manufacturing cycle.

– Normal UseNormal Use

• Car runs on solar energy, no significant Car runs on solar energy, no significant impact.impact.

– Disposal/RecyclingDisposal/Recycling

Ethical/Environmental AnalysisEthical/Environmental Analysis

• Environmental AnalysisEnvironmental Analysis

– Disposal/RecyclingDisposal/Recycling

• The plastic enclosure, which is not The plastic enclosure, which is not biodegradable, should be recycled. biodegradable, should be recycled.

• PCB, which contains hazardous PCB, which contains hazardous chemicals and metals, should be chemicals and metals, should be disposed of properly. disposed of properly.

• Encourage to recycle the entire system Encourage to recycle the entire system as a whole. as a whole.

Design ComponentsDesign Components

• Packaging design considerationsPackaging design considerations• Schematic design considerationsSchematic design considerations• PCB layout design considerationsPCB layout design considerations• Software design considerationsSoftware design considerations

Packaging DesignPackaging Design

Schematic DesignSchematic Design

• Power Supply Design (page 3)Power Supply Design (page 3)

Schematic DesignSchematic Design

• Microcontroller Block (page 2)Microcontroller Block (page 2)

Schematic DesignSchematic Design

• PLD/LCD Block (SPI and I2C) (Page 2)PLD/LCD Block (SPI and I2C) (Page 2)

Schematic DesignSchematic Design

• CAN Communications (page 3)CAN Communications (page 3)

Schematic DesignSchematic Design

• RS232 Communications (page 3)RS232 Communications (page 3)

Schematic DesignSchematic Design

• Button Interface (page 1)Button Interface (page 1)

Schematic DesignSchematic Design

• Optoisolators (page 1)Optoisolators (page 1)

Schematic DesignSchematic Design

• LEDs (page 1)LEDs (page 1)

Schematic DesignSchematic Design

• Analog and Buzzer (page 1)Analog and Buzzer (page 1)

PCB layout design ConsiderationPCB layout design Consideration

• Trace SizeTrace Size

– POWER / GND: 40 mils tracesPOWER / GND: 40 mils traces– Signal: 12 mils tracesSignal: 12 mils traces– Minimum space between two traces = 8 milsMinimum space between two traces = 8 mils

• Component PlacementComponent Placement

– Analog components must be separated from Analog components must be separated from Digital components to avoid digital noise couplingDigital components to avoid digital noise coupling

– Active components are placed on Top layer and Active components are placed on Top layer and Passive are placed on Bottom layer.Passive are placed on Bottom layer.

– Right Angle connectors are hanging over the Right Angle connectors are hanging over the boundary for easier accessibility. boundary for easier accessibility.

PCB layout design ConsiderationPCB layout design Consideration

• Component PlacementComponent Placement

– Mounting holes located at 1.375 inches from the Mounting holes located at 1.375 inches from the center of the board.center of the board.

– Components within each functional block should Components within each functional block should be closed to each other to minimize trace length.be closed to each other to minimize trace length.

– The boarder of some footprints should use The boarder of some footprints should use insertion outline to avoid placement errors.insertion outline to avoid placement errors.

Final PCB layoutFinal PCB layout1.375 inch

Initial PCBInitial PCB

• Component PlacementComponent Placement

– Mounting holes located at 1.375 inches from the Mounting holes located at 1.375 inches from the center of the board.center of the board.

– Components within each functional block should Components within each functional block should be closed to each other to minimize trace length.be closed to each other to minimize trace length.

– The boarder of some footprints should use The boarder of some footprints should use insertion outline to avoid placement errors.insertion outline to avoid placement errors.

Final PCBFinal PCB

Please include final PCB picture here if available.Please include final PCB picture here if available.

Software DesignSoftware Design

Success Criteria DemonstrationsSuccess Criteria Demonstrations

1.1. An ability to display vehicle status information on An ability to display vehicle status information on an LCD. an LCD.

2.2. An ability to navigate display menus and make An ability to navigate display menus and make selections using an RPG. selections using an RPG.

3.3. An ability to perform LCD backlight power An ability to perform LCD backlight power management management

4.4. An ability to obtain vehicle diagnostic information An ability to obtain vehicle diagnostic information via the CAN bus. via the CAN bus.

5.5. An ability to switch to “debug” mode (when a RS-An ability to switch to “debug” mode (when a RS-232 cable is connected) in which a diagnostic menu 232 cable is connected) in which a diagnostic menu is displayed. is displayed.

PSSC Demo Video

Individual ContributionsIndividual Contributions

• Team Leader – (Jason)Yuk Hang ChanTeam Leader – (Jason)Yuk Hang Chan• Team Member 2 – Nathanael HuffmanTeam Member 2 – Nathanael Huffman• Team Member 3 – (David) Wei Zhou Team Member 3 – (David) Wei Zhou • Team Member 4 – David SungTeam Member 4 – David Sung

Team Leader – Yuk Hang ChanTeam Leader – Yuk Hang Chan

• System menu designSystem menu design– Menu treeMenu tree– Navigated by RGP buttons Navigated by RGP buttons

• Debug menu designDebug menu design– Serial cable detectSerial cable detect– Menu controlMenu control

• Idle page display (Speed, Bar graph)Idle page display (Speed, Bar graph)• Configuration of RPG buttonsConfiguration of RPG buttons

Member 2 – Nathanael HuffmanMember 2 – Nathanael Huffman

• Hardware Design Hardware Design • Schematic Schematic • PCBPCB• Hardware Assembly Hardware Assembly • Hardware DebuggingHardware Debugging• Packaging Packaging • Cable Harnesses Cable Harnesses

Member 3 – David Wei ZhouMember 3 – David Wei Zhou

• Initialization Of All Peripherals Initialization Of All Peripherals • TimerTimer• InterruptInterrupt• A/D channel (sensors)A/D channel (sensors)• CAN bus communication CAN bus communication

– Sending CAN message (polling base)Sending CAN message (polling base)– Receiving CAN message (Interrupt base)Receiving CAN message (Interrupt base)

• Debug Menu Data display Debug Menu Data display

• Completion of PCB design and layoutCompletion of PCB design and layout• Completion of Senior Design Report and Completion of Senior Design Report and

User ManualUser Manual• Checking the Ethical/Environmental designs Checking the Ethical/Environmental designs

of our projectof our project• Involved in initial component selection and Involved in initial component selection and

finding datasheet for each componentfinding datasheet for each component

Member 3 – Yuan-Jiun SungMember 3 – Yuan-Jiun Sung

Project SummaryProject Summary

• Important lessons learnedImportant lessons learned– Contribution to Purdue Solar teamContribution to Purdue Solar team– Inter-teamInter-team

• Cooperate with two other teamsCooperate with two other teams– Developed CAN protocolDeveloped CAN protocol– Developed interface specifications Developed interface specifications

– Intra-teamIntra-team• Hardware vs. Software (communication)Hardware vs. Software (communication)• Keep motivatedKeep motivated• Start software early!Start software early!• Should prepare timeline in early design stageShould prepare timeline in early design stage

Project SummaryProject Summary

• Version 2 changes Version 2 changes • Enhance menu system expandability Enhance menu system expandability • CAN cable detectionCAN cable detection

– Device won’t function without CAN cable Device won’t function without CAN cable connectedconnected

• Dedicated CAN buffer to ensure ability to Dedicated CAN buffer to ensure ability to handle busy traffic handle busy traffic

• Bigger PLDBigger PLD• Solar Team will continue on the projectSolar Team will continue on the project

Questions / DiscussionQuestions / Discussion