Pulsar Dreamcast BLE

Use your Dreamcast controller wirelessly with any Bluetooth device. Pulsar speaks the Dreamcast's Maple Bus protocol natively and presents itself as a standard Xbox One S BLE gamepad — just plug in, pair, and play.

Features

• All Dreamcast inputs: A/B/X/Y, Start, D-pad, analog stick, analog triggers
• Works with any BLE HID host (PC, iOS, Android, Switch, Dreamcast via iBlueControlMod)
• 60Hz controller polling with continuous BLE reporting
• Pairing persists across power cycles (flash-based bonding)
• Battery powered (~7-8 hrs on 500mAh, ~14-16 hrs on 1000mAh) with sleep/wake support
• 3D-printable VMU-shaped enclosure included

Compatibility

Controllers

• Standard Dreamcast controller (first-party tested)

Hosts

Tested:

• Steam Deck (as Xbox gamepad)
• macOS (as Xbox gamepad)
• Dreamcast (via iBlueControlMod adapter)

Should work (untested):

• Windows, Linux (as Xbox gamepad)
• iOS, Android (as BLE HID gamepad)
• PlayStation, Nintendo Switch (as generic controller)

Build Your Own

What You Need

• Seeed XIAO nRF52840
• Dreamcast controller
• 5V boost converter (for battery mode)
• 2x 10kΩ resistors
• LiPo battery
• USB cable (for UF2 flashing) or debug probe (for development)

See the full bill of materials for details.

Wiring

Connect SDCKA and SDCKB from the controller cable to the XIAO with 10kΩ pull-ups to 3.3V. The controller needs 5V power via a diode OR circuit (USB + boost converter). See pin mapping for the complete wiring reference.

Flash

Pre-built firmware is available on the Releases page.

UF2 (recommended — no debug probe needed):

The XIAO ships with a UF2 bootloader that includes the Nordic SoftDevice. Just double-tap the reset button — the board mounts as a USB drive (XIAO-BOOT) — then copy the .uf2 file:

cp pulsar-dreamcast-ble.uf2 /Volumes/XIAO-BOOT/

The board auto-resets and runs the firmware.

SWD (for development — requires J-Link or nRF52840 DK):

If you need RTT debug logging, flash via SWD instead. The SoftDevice must be flashed separately first — see flash commands for the full workflow.

Pair and Play

1. Power on the adapter — it starts advertising immediately
2. On your host device, scan for "Xbox Wireless Controller"
3. Pair and you're done — bonding is saved automatically

Sync button:

• Hold 3 seconds → clear bond and start pairing
• Triple-press → toggle device name (Xbox / Dreamcast)

See the user guide for more details.

Enclosure

A 3D-printable VMU-shaped case is included in 3d_files/. See 3d_files/README.md for print tips and attribution.

For Developers

Building from Source

Requires Rust stable with thumbv7em-none-eabihf target:

rustup target add thumbv7em-none-eabihf
cargo install cargo-embed

XIAO (must use --release — debug builds break Maple Bus timing):

# Production
cargo embed --release --no-default-features --features board-xiao

# Development (with RTT debug logging)
cargo embed --release --no-default-features --features board-xiao,rtt

DK (RTT always enabled):

cargo embed --release

Testing

The maple-protocol crate is pure Rust with no embedded dependencies — tests run on the host:

cd maple-protocol && cargo test

Architecture

The project is split into two crates:

• maple-protocol/ — Pure protocol library: controller state parsing, packet construction, Xbox HID report generation. No hardware dependencies, fully host-testable.
• src/ — Firmware: Maple Bus GPIO bit-banging, BLE stack (Nordic SoftDevice S140), board support, button handling, power management.

The GPIO implementation uses bulk sampling at ~12.5MHz to capture the 2Mbps Maple Bus protocol. This is an nRF52840-specific approach — other chips (e.g., RP2040 with PIO) could implement the same protocol differently. See maple_bus_protocol.md for the full protocol reference.

Running Checks

./scripts/ci.sh

Runs formatting, tests, clippy, and release builds for both board targets.

Documentation

Document	Description
User Guide	Non-technical guide to using the adapter
Bill of Materials	Parts list for building your own
Pin Mapping	Complete wiring reference for both boards
Flash Commands	Flashing and debugging cheat sheet
Maple Bus Protocol	Protocol reference and implementation details
Battery Optimization	Power management strategy
Learnings	Implementation lessons learned

Releases

Pre-built firmware is available on the Releases page. Each release includes:

• pulsar-dreamcast-ble-xiao.uf2 — XIAO firmware, drag-and-drop via UF2 bootloader
• pulsar-dreamcast-ble-xiao.hex — XIAO firmware, for flashing via J-Link/SWD
• pulsar-dreamcast-ble-dk.hex — DK firmware, for flashing via J-Link

3D scan archives are also attached to releases.

Contributing

Contributions are welcome! See CONTRIBUTING.md for build instructions, project structure, and how to submit changes.

License

This project is licensed under the GNU General Public License v3.0 or later. 3D model files have separate licensing — see 3d_files/README.md.