Getting Started

Getting Started

Option A: Flash pre-built firmware (no toolchain required)

1. Download OBDisplay-Uno-<version>.hex from the Releases page.
2. Flash with avrdude (included with the Arduino IDE, or install separately):

avrdude -c arduino -p atmega328p -P /dev/ttyUSB0 -b 115200 \
  -U flash:w:OBDisplay-Uno-<version>.hex:i

Replace /dev/ttyUSB0 with your port (COM3 on Windows, /dev/cu.usbmodem* on macOS).

The release also ships OBDisplay-Uno-<version>.elf for symbol-level debugging (avr-gdb, avr-nm). You cannot flash it directly.

Option B: Build from source

Install PlatformIO

pip install platformio
# Arch Linux:
sudo pacman -S platformio-core

Or install the PlatformIO extension for VS Code.

Clone and build

git clone https://github.com/RXTX4816/OBDisplay-Uno.git
cd OBDisplay-Uno

# Build only
pio run -e uno

# Build and upload
pio run -e uno --target upload

# Run host-side unit tests (no Arduino required)
pio test -e native

Build environments

Environment	Command	Use
uno	pio run -e uno	Production — smallest binary, no serial output
uno_debug	pio run -e uno_debug	Debug build — binary frame logging over USB serial
native	pio test -e native	Host-side model unit tests

First use

Power on with SELECT held → auto-setup: skips the menus and connects immediately at baud 10400, address 0x17 (instruments).

Power on normally → interactive setup:

1. Baud rate — LEFT/RIGHT to cycle (1200 / 2400 / 4800 / 9600 / 10400), SELECT to confirm
2. ECU address — LEFT/RIGHT to cycle supported addresses, SELECT to confirm
3. Auto-reconnect — LEFT = off (manual), RIGHT = on (auto)

Once connected the Cockpit screen appears and data updates live.

ECU emulator (bench testing)

OBDisplay-Emu turns an Arduino Mega into a KWP-1281 ECU emulator for bench testing without a car.