Deo Nano Beginer problem

You need special motor drive electronics to interface motors to PWM circuits. If you don't have that correct you can damage the output pins on the FPGA. An FPGA pin operates at a very low voltage and sources a tiny amount of current (3.3 volts at 8 microamps iirc?). The l293d is an hbridge driver. I know nothing about motors, but I've only seen hbridge circuits used to drive motors at full power in either forward or reverse. I've never seen them used with pwm. Someone who knows about motors can tell you where to find a good circuit to control a DC motor with a FPGA generated pwm signal.