q3-dsb-labs/ch4/motorcontrol.sv

`timescale 1ns/1ps

module motorcontrol #(parameter N=21)
   (input logic clk,
    input logic rst,
    input logic direction, 
    input logic [N-1:0] count_in,
    output logic pwm);

	typedef enum logic[1:0] {reset, high, low} pwm_state;
	pwm_state state, next_state;

	always_ff @(posedge clk) 
		if (rst)
			state <= reset;
		else 
			state <= next_state;

	always_comb begin
		case (state)
			reset:
				begin
					pwm = 0;
					next_state = high;
				end 
			high:
				begin
					pwm = 1;
					if (direction == 0 && count_in >= 21'd100_000)
						next_state = low;
					else if ( direction == 1 && count_in >= 21'd200_000)
						next_state = low;
					else 
						next_state = state;
				end
			low: 
				begin
					pwm = 0; 
					next_state = state;
				end 
			default: 
				begin
					pwm = 0; 
					next_state = reset;
				end 
		endcase
	end
endmodule