CAN NETWORK

Steering InterfaceμController Module

Display InterfaceμController Module

Motor InterfaceμController Module

Driver Inputs

Signal Controller

Sensor Inputs

Vehicle Controls

Motor ControllerDriver Display

Wireless Modem

Battery ProtectCircuit

|Helio |Link Ltd.

•Functionally arrange components into 3 nodesNode #1: Motor Controller ModuleNode #2: Driver Display ModuleNode #3: Steering Column Module

•Connect the nodes using CAN technology•Develop common hardware at each nodeBased around the Freescale HCS12 CPUFlexible, to serve all I/O needs at each node

•Use CodeWarrior to develop software to control all of the network’s functionsSerial communicationsAnalog to Digital ConversionCAN interfaceLCD Driver DisplayInterrupt driven inputGeneral Purpose I/O

Auburn’s Solar Car Racing Team approached the Electrical Engineering department with a request for a networked system of microcontrollers to replace their current vehicle’s wiring harness to resolve these issues:

•Excess weight associated with the current harness•Reliability issues with the quantity of wires•Difficulty in modifying the electronics configuration•Driver safety issues resulting from component failures

Team |Helio|Link Is: |Mike Cornelison |Beau Eckerman |David Last |Aaron Steiner |Luke Stewart |Brian Whitehouse

• Increased communication among the three sections of the car

• Reduced weight• Increased reliability• Added level of safety• Easily reconfigurable / expanded

•Maximum power draw: 12W (1A @12VDC)•Minimize weight added to the vehicle•Keep development and production costs low•Replace all system I/O and communication with the CAN•Make functionally ubiquitous to driver and chase vehicle•Ensure safety of driver in case of network failures

•Developed a architecture capable of interconnecting all vehicle sub-systems•Designed custom node hardware for the CAN physical layer (not built)Powerful HC9S12 microcontrollerTwo CAN interfacesTwo RS-232 interfacesLCD controllerMixed signal input/output

•Coded control software to implement all I/O functions & serial communicationsCAN messaging and priority assignmentRS-232 control and pass-through capableADCLCD display controllerInterrupt driven user interfaceGPIO

Main FunctionMain Function

MotorController

Node

DisplayNode

SteeringControls

Node

MainFunction

Initialize CANMessaging

InitializeInput/Output Pins

InitializeLCD Display

InitializeSerial Interface

Clear Display

Read Throttle On/Off

Read MotorController Direction(Forward/Reverse)

Read MotorController On/Off

Display Current Speed

Display Desired Speed

Display CruiseControl On/Off

Display Trip Odometer

Display Throttle Position

Display Throttle On/Off

Display Up-Time Clock

Display MotorController On/Off

Display Motor Controller Direction (Forward/Reverse)

Display MPH/KPH

Transmit ThrottleOn/Off Over CAN

Transmit MotorController Direction

Over CAN

Transmit MotorController On/Off

Over CAN

Transmit SerialOver CAN

MPH/KPH PushButton Toggle

Receive CAN Messages

Receive Serial TrafficFrom Wireless Modem

Interrupts

InitializeSerial Interface

Initialize MotorController ForSerial Control

Initialize CANMessaging

Set Motor ControllerOn/Off

Set Motor ControllerMode

(Torque/Cruise)

Set Motor Direction(Forward/Reverse)

Set DesiredMotor Current

Set Target Speed

Read Page 1 Data

Transmit Serial TrafficOver CAN

Send Serial TrafficTo Motor Controller

Transmit SpeedOver CAN

Receive CAN Messages

Receive Serial TrafficFrom Motor Controller

Interrupts

MainFunction

Initialize CANMessaging

InitializeAnalog-to-Digital

Converter

InitializeInput/Output

Pins

Read Throttle Potentiometer

Send ThrottlePosition Over

CAN

Send CruiseControl Status

Over CAN

Send DesiredSpeed Over

CAN

MainFunction

Cruise Control On/Off

Cruise Control Increment

Cruise Control Decrement

Receive CAN Messages

Interrupts

•Displays vehicle information to the driver such as speed and throttle position•Features motor ignition, trip odometer, MPH/KPH toggle, and time-of-operation clock•Receives data from chase vehicle via RS-232 serial connection to wireless modem

•Allows driver to control throttle and braking using a potentiometer•Provides cruise control with increment/decrement controls•Sends throttle and cruise control information over CAN to motor controller and display

Freescale HC9S12DG128 Microcontroller:•16-bit HCS12 CPU•128kB Flash EEPROM, 8kB RAM, 2kB EEPROM•2x SCI, 3x CAN 2.0 A & B (1Mb/sec), I2C•2 8-channel, 10-bit ADCs•PWM, Enhanced Capture Timer•29 GPIO Lines•Low power operation modes

Panasonic PCA82C250N CAN Transceiver:•High speed (1Mb/s) transceiver module•Handles arbitration, packet formation

Texas Instruments MAX202 RS-232 Transceiver:• Dual RS-232 level converters and line drivers

ON Semiconductor MC34164 μC Supervisor:•Under-voltage & power-on reset sensing

64-pin Header:•Driver Display Interface•8-Channel ADC Connection•9 Interrupt Capable Inputs•8 Enhanced Capture Timers•22 GPIO

6-Pin ISP Connection:•Breaks out the ISP & In-system debug module

Network & Power Connector:•2-Wire CAN network interface•+12VDC Power in

|Helio |Link Ltd.

•Exchanges data with motor controller via RS-232 serial communication•Sends serial data from motor controller over CAN to display and steering node•Sends CAN data to motor controller over serial connection

μC

CAN0CAN4

RS-232RS-232

GPIO

Network

Wireless Modem

•Motor Ctrlr. Enable•Throttle Enable•Direction Toggle•Mph/kph Toggle•Odometer Reset

Push Buttons

Interrupts

Driver Display

μC

CAN0CAN4

RS-232RS-232

GPIOADC

Network

Motor Controller

•To turn signal & brake light controller

•Battery Current•Backup Battery Voltage•Solar Array Current

μC

CAN0CAN4

RS-232RS-232

GPIOADC

Network

Batter ProtectionCircuit

•Acceleration•REGEN

Push Buttons

Interrupts

•Cruise Control Set•Cruise Control Up•Cruise Control Down•Left Blinker•Right Blinker