ABSTRACT This paper presents an encoder calibration system to enhance resolution and accuracy in an interior permanent magnet synchronous motor (IPMSM) drive, along with custom embedded software. The system implements closed-loop control with the IPMSM drive, adjusting the encoder resolution through gear ratio adjustments. Communication between the human-machine interface (HMI) and the DSP’s internal 28× CPU is achieved via digital communication RS-422 interface. The embedded software on the 28× CPU processes real-time data and displays calibration information on the HMI. Firmware integration includes external analog/digital converters, comparators, digital communication interfaces, high-accuracy encoders, original encoders, and additional gear ratio adjustments, with computed compensation values stored in EEPROM. The TMS-320F-28335 digital signal processor serves as the control core, enabling encoder signal processing, embedded software execution, HMI operation, and IPMSM drive control. The experimental results validate the practicality of the proposed digitization method, demonstrating its effective applicability in industrial control systems.