The direction controller is a small PCB used as a driver interface to select drive direction. It does not contain any logic, just enough to make 3 buttons and 3 LEDs available to the driver:
- Forward
- Neutral
- Reverse
The button state is communicated to the DIY VCM which controls the state of the LEDs.
Hardware
The hardware is created using KiCad and can be found in the vehicle-controller GitHub repository.
PCB
TBD.
Connectors
The direction controller has four 4-pin JST-PH connectors:
- Connector housing: JST PHR-4
- Crimp contact: JST SPH-002T-P0.5S
Main connector
| Pin | Function |
|---|---|
| 1 | CAN High |
| 2 | CAN Low |
| 3 | +12 V (Ignition) |
| 4 | GND |
Button connectors (×3)
The button connector has the same pinout for forward, neutral and reverse:
| Pin | Function |
|---|---|
| 1 | LED Anode |
| 2 | LED Cathode |
| 3 | Button |
| 4 | Button |
The current-limiting resistors on the PCB are sized to provide ~10 mA to the following LED forward voltages. If different LEDs are used, the resistors R?, R? and R? may need to be replaced.
- Forward: 2.8 V (blue)
- Neutral: 3.5 V (white)
- Reverse: 2.8 V (blue)
Firmware
The firmware for the STM32G431CB is written in Rust using Embassy and is very simple. It listens to a TBD frame from TBD CAN containing the LED state, and responds with a frame containing the state of the push buttons.
The firmware lives in the vehicle-controller GitHub repository.