Center Console is the only driver interface. It controls all power transitions, motor output and steering lights. It also displays BMS data, vehicle speed and has LED indicators. This board is always on when the car is on.

Rundown of Center Console Functions:

• Buttons to change state

  • Drive, Reverse, and Neutral

  • Regen Braking button

  • Hazard Button

• three 7-segment displays with the below quantities

  • Speedometer (speed in km/h)

    • When we BPS fault it will display the error code instead

  • Current Readings (Amps)

  • Aux Battery Voltage (Volts)

• Indicator LEDs

  • One for each of the above buttons (D/N/R/Haz/Reg)

  • Left turn signal

  • Right Turn Signal

  • Cruise control enabled indicator

  • BPS Fault Light

  • AFE Loss of Communications

• Buzzer to highlight events

  • Button Clicks

  • BPS fault

• Pedal Position

  • Maps ADC reading from 0-1 for the Motor Controller

  • Stores pedal calibration data in flash non-volatile memory

  • Refer to FW15 Pedal Board Design for more documentation! This board has been merged to CC. It is almost the same, but it doesn’t use the MAX11600. It instead uses a pedal that we ripped off a car

• Steering Stalk

  • Toggles Left/Right lights

  • Toggles Cruise Control

  • Refer to FW15 Steering Design for more documentation! This board was merged to CC so it hasn’t really changed
    
    

Centre Console Functionality

Module: cc_buttons

This module gets all button values. Buttons should be read in the fast cycle. They are connected to the pca9555 gpio expander, and must be read over i2c. This read function should send notifications to the requisite tasks.

• Power Button, hazard, regen: send notifications to main task

• R, N, D → Send notifications to Drive FSM

Module: update_dashboard

Static variables:

• cruise_control_state

• target_velocity

• regen_braking_state

• power_state_to_transmit

Functions (all called in medium cycle):

• dashboard_init()

• update_indicators()

  • Gets notification value from button presses, updates indicator lights and output can_messages

    • Hazard enabled:

      • when pressed, toggle static hazard state

      • update indicator and cc_power_control.hazard_enabled message based on stored value

    • Regen Brake:

      • when pressed, toggle static regen brake state

      • update indicator and drive_output.regen_brake_enabled message based on stored value

    • Lights left/right

      • update left/right indicator based on steering stalk position

    • Cruise Control Enabled:

      • update static cc state + indicator based on steering stalk ISR (Button click)

      • update drive_output based on cc_state + target_velocity

• update_displays() [SEPERATE TASK]

  • Reads values from CAN messages, uses values for 7-seg:

    • Calculated speed using RPM to MPH → speed display (Top)

    • Current reading in Amps → current display (Middle)

    • Aux Battery Voltage → aux batt display (Bottom)

• cruise_control_monitor()

  • Checks for cruise control inputs from steering stalk

  • Updates Cruise control target speed

Module: pedal

Module: steering

Drive FSM

The Drive FSM handles the control of drive state of the car. It receives the drive buttons (Neutral (N), Drive (D), Reverse(R)) and runs the preparations and checks needed to change the drive state of the car, and communicates this value with the motor controllers.

The initial/default state is Neutral. This is the mandated state of the FSM when we start the car up and are in POWER_IDLE state. In addition, any major faults should force the car into neutral.

The drive state is dependent on power_state. We expect to receive this message every cycle, and if we do not receive this message, we will record a fault after 3 cycles and enter neutral.

State Input Functions:

All the following must be met for a transition to happen from the following states

Neutral → Drive/Reverse

• Button pressed (D/R)

• Power state == POWER_DRIVE (received from Power distribution)

• Speed == 0: All drive state transitions should happen when we are stopped

Actions:

• Runs precharge, and closes motor relay

• Transmit DRIVE/REVERSE state to MCI

Drive/Reverse → Neutral

• Neutral button or forced because of fault

• Transmit NEUTRAL state to MCI

Reverse → Drive OR Drive → Reverse

• Since we are an EV we can do this easily! Transmits NEW_STATE to MCI

Power State FSM - Moved to Power Distribution

Power FSM

The power FSM governs the power state of the car. There are 4 main States:

• POWER_OFF

• POWER_MAIN

• POWER_AUX

• POWER_FAULT

For the main power states however, when we are transitioning there is a sequence of checks we run to make sure that the system is in a correct state to allow a transition. These steps typically involve sending a CAN message to another system, waiting for it to do its checks and balances and then receiving an acknowledgement (ACK) message. If these checks fail, we will transition back to the normal power state.

The sequence model for these states is along the following lines:

• All steps must be executed successfully before a transition can take place

• If a step fails, we should handle the error and remain in the current state

The diagram is shown below, hexagons representing the sequence steps. The states themselves have no real functionality in their output functions.

Open

Power FSM Diagram

Power Aux Sequence*

1. Confirm a valid aux status has been received from Power Select Info message

   1. Correct status bits should be set in the message

   2. No fault bits should be set

2. Transmit TURN_ON_EVERYTHING to Power Distribution and receive BPS heartbeat

   1. Once Power Distribution has turned everything on, we wait for BMS to power up and send heartbeat message, indicating that the power on was successful

*From Power Aux, if a fault condition is detected (ie invalid power select status message) we should return to off

Power main sequence

1. Confirm Aux Status

   1. Confirm no issues with aux supply at Power Select

   2. Check power select message for valid aux status, and no faults

2. Power on boards

   1. Tell Power distribution to power on all outputs

3. Confirm battery status

   1. Wait for BMS to start up and reply with a Heartbeat and status message

   2. This indicates initial state is all good

4. Close Relays

   1. Transmit message to BMS to close relays and switch to main power

   2. Transmits to BMS to close relays

5. Confirm DCDC

   1. Check at power select that main power (DCDC) is now in use

6. Power Main Complete

   1. Sends “ready to drive” to MCI

   2. Start BPS watchdog

Fault

• This state covers a BPS fault during operation. It occurs if we receive a message from BMS saying that we have a fault condition

  • If a message is received saying that a fault has occurred, then we can attempt to handle the specific fault

  • Car must be power-cycled and then put into drive to clear the persisted fault

  • BPS indicator is on during this time