Developed support for the Kempston Mouse Interface within the mamedev/mame repository, enabling two-button mouse input with X and Y movement tracking for Spectrum bus emulation. This work involved implementing a dedicated slot device that integrates seamlessly with the existing Spectrum bus infrastructure, ensuring compatibility and stability across the emulation platform. The approach focused on aligning the new input device with the established slot and device framework, maintaining consistency in hardware interfacing. Utilizing C++ for device driver development, the contribution enhanced input fidelity for Spectrum emulation and broadened hardware compatibility, addressing the need for more accurate and flexible user input options.