Design of programmable filter based on microcontroller

Abstract The system is designed with a microcontroller (AT89S52) as the core, developed based on the Keil 51 software system, combined with LCD display and necessary peripheral circuits to form a programmable controlled high-precision filter. The system mainly consists of the amplifier module, filter module, parameter setting and LCD display module, and amplitude-frequency characteristic testing module. The programmable control of the amplifier consists of a D/A converter DAC0832 and a programmable filter MAX262. By setting the amplifier and filter parameters on the keyboard, the gain and step adjustment can be achieved with high accuracy. The amplitude-frequency characteristic test signal source is implemented by DDS. Due to the use of a software operating system and a Chinese LCD module for display, this programmable filter provides a very user-friendly human-computer interaction interface.