Design and Implementation of Multiple PWM Channels using Universal Asynchronous Receiver Transmitter

Abstract

Universal Asynchronous Receiver Transmitter (UART) is a communication protocol used for sending and receiving the serial data. It offers short distance communication and it is reliable as well. This paper presents the application of UART module for creating Multiple Pulse Width Modulation (PWM) channels having different duty cycles using serial terminal on Field Programmable Gate Arrays (FPGA). The user can control the duty cycle of the PWM signals through serial terminal. UART module designed for this application features technique for baud rate detection. The design has been synthesized using Verilog Hardware Description Language (HDL) on Lattice Mach XO2 FPGA over a Tiny FPGA A2 module using Lattice Diamond Design software. A Printed Circuit Board (PCB) has been designed to observe the effects of PWM signals with different duty cycles over multiple Light Emitting Diodes (LEDs). The design is verified through simulations and logic analyzer tool. Effects of PWM signals is also observed through the intensity of Multiple LEDs. Maximum frequency that can be obtained on Lattice Mach XO2 FPGA is 133 MHz. The design uses 12.08 MHz frequency for the system clock.