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Spb2005 edited this page Feb 16, 2026
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This Wiki documents the reverse engineering of the Thrustmaster T248 steering wheel and the development of a fully functional wheel emulator for custom steering wheels.
The objective is to understand the hardware architecture, communication protocol, and firmware behavior well enough to electronically emulate the original wheel on a stock T248 wheelbase.
Current state of the research:
- UART communication protocol largely decoded
- Startup and keep-alive mechanism fully understood
- Button and encoder transmission working reliably
- RP2040-based wheel emulator (V2.0) fully operational
- Custom wheels confirmed working on stock wheelbase
- Display data decoding still incomplete
- Firmware update mechanism partially understood
The T248 system consists of:
- Wheelbase (main MCU + motor control)
- Steering wheel (secondary MCU + inputs + display)
- UART communication link between wheel and base
- Firmware update mechanism via PC software
The emulator replaces the original steering wheel electronics while preserving electrical and protocol compatibility.
System architecture, communication concept, and design philosophy.
Physical and electrical reverse engineering:
- Wheel disassembly
- PCB analysis
- Wheel connector pinout
- Encoders
- Display module
- Pedal set
- Wheelbase internals
Complete UART protocol documentation:
- UART configuration
- Startup sequence
- Normal operation
- Keep-alive frames
- Button frames (B0 / B1)
- General data frames (F3)
- Display data frames
- Shutdown sequence
Implementation details:
- Emulator architecture
- Development history (V1.x evolution)
- V2.0 stable implementation
- DIY schematic
Low-level firmware investigation:
- SWD debug interface
- Firmware structure
- Firmware update mechanism
- Resolved questions
- Open questions
- Future work roadmap