1. ECE 477 Design Review Team 14  Spring 2006 Jason, Nathanael, David, David

2. Project Overview Driver interface for Solar Racing TeamDriver interface for Solar Racing Team Communication with onboard power trackers and telemetry board via CAN busCommunication with onboard power trackers and telemetry board via CAN bus Display speed, battery power, and other information on the LCDDisplay speed, battery power, and other information on the LCD Allow driver to navigate through a text-based interface to customize display information and issue commands to the power trackersAllow driver to navigate through a text-based interface to customize display information and issue commands to the power trackers

3. Project-Specific Success Criteria An ability to display vehicle status information on an LCD.An ability to display vehicle status information on an LCD. An ability to navigate display menus and make selections using an RPG.An ability to navigate display menus and make selections using an RPG. An ability to perform LCD backlight power management (e.g., turn the backlight on for X seconds after the RPG is turned/pressed).An ability to perform LCD backlight power management (e.g., turn the backlight on for X seconds after the RPG is turned/pressed). An ability to obtain vehicle diagnostic information via the CAN bus.An ability to obtain vehicle diagnostic information via the CAN bus. An ability to switch to “debug” mode (when a RS-232 cable is connected) in which a diagnostic menu is displayed.An ability to switch to “debug” mode (when a RS-232 cable is connected) in which a diagnostic menu is displayed.

4. Block Diagram

5. Component Selection Rationale Design constraintsDesign constraints –Microcontroller 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 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-lossHigh efficiency to reduce power-loss

6. Component Selection Rationale MicrocontrollerMicrocontroller (PIC18F series with CAN, I2C, UART, PWM) –PIC18F4680 (44pin TQFP) Cost: $6.08 *** 64Kb Flash64Kb Flash 36 I/O36 I/O –PIC18F2680 (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, but PLD cost increase is greater than $0.54Could use larger/different PLD to expand I/O, but PLD cost increase is greater than $0.54

7. Component Selection Rationale Power Supply (~400mA @ 5VDC)Power Supply (~400mA @ 5VDC) –MAX744A 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 *** 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

8. Packaging 3.25 inch 5.63 inch 1.81 inch

9. Packaging design Design constraintsDesign constraints –Dark inside the solar car –Simple control –Noise level –Vibration level –Size (small cockpit)

10. Plastic Enclosures LCD displayLCD display –Backlight is needed –Font need to be readable ConnectorsConnectors –6-pin MTE connector. –RS232 serial port InterfacingInterfacing –Push buttons –LED indicators Packaging

11. Interfacing buttons will be mount on the steering wheel.Interfacing buttons will be mount on the steering wheel. –RPG buttons –Return –Main Menu PushbuttonsPushbuttons DisplayDisplay Packaging

12. Schematic/Theory of Operation Power Supply Design (page 3)Power Supply Design (page 3)

13. Schematic/Theory of Operation Microcontroller Block (page 2)Microcontroller Block (page 2)

14. Schematic/Theory of Operation PLD/LCD Block (SPI and I2C) (Page 2)PLD/LCD Block (SPI and I2C) (Page 2)

15. Schematic/Theory of Operation CAN Communications (page 3)CAN Communications (page 3)

16. Schematic/Theory of Operation RS232 Communications (page 3)RS232 Communications (page 3)

17. Schematic/Theory of Operation Button Interface (page 1)Button Interface (page 1)

18. Schematic/Theory of Operation Optoisolators (page 1)Optoisolators (page 1)

19. Schematic/Theory of Operation LEDs (page 1)LEDs (page 1)

20. Schematic/Theory of Operation Analog and Buzzer (page 1)Analog and Buzzer (page 1)

21. PCB Layout Design Overview Trace ConsiderationsTrace Considerations Component PlacementComponent Placement Placement ErrorsPlacement Errors Excluded design constraintsExcluded design constraints

22. Routing Consideration Size of TracesSize of Traces –POWER / GND: Standard = 40 mils, Min = 12 mils –Signal: Standard = 12 mils, Min = 8 mils –Minimum space between two traces = 8 mils –The Power and Ground should be routed first since they will take the most space on the PCB board.

23. Component Placement Analog components must be placed as far away from the digital components as possible to avoid digital noise coupling.Analog components must be placed as far away from the digital components as possible to avoid digital noise coupling. Crystal is placed close to the microcontroller to keep the clock signal clean and to prevent clock signal being coupled into other signals.Crystal is placed close to the microcontroller to keep the clock signal clean and to prevent clock signal being coupled into other signals. The components within each functional block should be placed as close together as possible to minimize the trace length.The components within each functional block should be placed as close together as possible to minimize the trace length.

24. Component Placement Mounting holes located at 1.375 inches from the center of the box.Mounting holes located at 1.375 inches from the center of the box. The active components are placed on the top layer and the passive components are placed on the bottom layer for easier interfacing, soldering, and debugging.The active components are placed on the top layer and the passive components are placed on the bottom layer for easier interfacing, soldering, and debugging. Decoupling capacitors are placed near the Micro power/ground pins to provide direct current to the IC.Decoupling capacitors are placed near the Micro power/ground pins to provide direct current to the IC. Header LocationHeader Location –MTE connectors (RS232 connector, CANbus connector) : Place near the edge of the board (to stick through the box). –Programming Header (Pic18 header, PLD header): Place near the component.

25. PCB Placement Errors To avoid placement errors, the border of the footprint must use insertion outlineTo avoid placement errors, the border of the footprint must use insertion outline Some placement errors are ok as long as they don’t interfere with the connectionsSome placement errors are ok as long as they don’t interfere with the connections Buzzer RS232

26. Excluded Common Design Constraints Heat sinking was not necessary in the PCB layout since we only have one major heat source – the DC-DC converter. But, it operates with high efficiency (low heat loss).Heat sinking was not necessary in the PCB layout since we only have one major heat source – the DC-DC converter. But, it operates with high efficiency (low heat loss). Copper Pours are not used since no components require it and most of components are digitalCopper Pours are not used since no components require it and most of components are digital

27. PCB Layout 1.375 inch 2.75 inch 4.5 inch

28. PCB Layout Major Layout SectionsMajor Layout Sections DCDC Converter CAN Interfaces PIC18 Micro Opto-isolator PLD RS232

29. Top Layer

30. Bottom Layer

31. Software Design/Development Status Major ChallengesMajor Challenges –CANBus Protocol CANopen LibraryCANopen Library Object DictionaryObject Dictionary Provided functionProvided function – Text menu RGP decoderRGP decoder LCD displayLCD display

32. Software Flow Chart Power Tracker

33. Project Completion Timeline

34. Questions / Discussion