PWM waveform generation using rotary encoder on Spartan-3E starter kit

Abstract

A PWM waveform generator with variable duty cycle has been designed and implemented in this paper. The design has been simulated for different frequencies. The waveform is generated on Spartan 3E FPGA starter kit which has on board rotary encoder. The on board clock signal and rotary encoder generates the required PWM signal. The duty cycle of PWM is varied by rotating the encoder in clockwise and anticlockwise directions. Various frequencies of PWM signal is generated by pressing it up and down. The design has been proposed where duty cycle can be varied from 0 to 100%. The frequency of the on board clock signal i.e., 50 MHz and this has been varied to generate different frequencies. The output can be observed on DSO and CRO. The PWM is used in controlling inverters, electrical motors and many communication and control applications. The usage of FPGA provides the reconfigurable architecture and also provides flexibility as well as economically viable.