ball.sv

module  ball ( input Reset, frame_clk,
					input [7:0] keycod,
               output [9:0]  BallX, BallY, BallS );
    
    logic [9:0] Ball_X_Pos, Ball_X_Motion, Ball_Y_Pos, Ball_Y_Motion, Ball_Size;
	 
    parameter [9:0] Ball_X_Center=320;  // Center position on the X axis
    parameter [9:0] Ball_Y_Center=240;  // Center position on the Y axis
    parameter [9:0] Ball_X_Min=0;       // Leftmost point on the X axis
    parameter [9:0] Ball_X_Max=639;     // Rightmost point on the X axis
    parameter [9:0] Ball_Y_Min=0;       // Topmost point on the Y axis
    parameter [9:0] Ball_Y_Max=479;     // Bottommost point on the Y axis
    parameter [9:0] Ball_X_Step=1;      // Step size on the X axis
    parameter [9:0] Ball_Y_Step=1;      // Step size on the Y axis

    assign Ball_Size = 4;  // assigns the value 4 as a 10-digit binary number, ie "0000000100"
   
    always_ff @ (posedge Reset or posedge frame_clk )
    begin: Move_Ball
        if (Reset)  // Asynchronous Reset
        begin 
            Ball_Y_Motion <= 10'd0; //Ball_Y_Step;
				Ball_X_Motion <= 10'd0; //Ball_X_Step;
				Ball_Y_Pos <= Ball_Y_Center;
				Ball_X_Pos <= Ball_X_Center;
        end
           
        else 
        begin 
				 if ( (Ball_Y_Pos + Ball_Size) >= Ball_Y_Max )  // Ball is at the bottom edge, BOUNCE!
					  Ball_Y_Motion <= (~ (Ball_Y_Step) + 1'b1);  // 2's complement.
					  
				 else if ( (Ball_Y_Pos - Ball_Size) <= Ball_Y_Min )  // Ball is at the top edge, BOUNCE!
					  Ball_Y_Motion <= Ball_Y_Step;
					  
				  else if ( (Ball_X_Pos + Ball_Size) >= Ball_X_Max )  // Ball is at the Right edge, BOUNCE!
					  Ball_X_Motion <= (~ (Ball_X_Step) + 1'b1);  // 2's complement.
					  
				 else if ( (Ball_X_Pos - Ball_Size) <= Ball_X_Min )  // Ball is at the Left edge, BOUNCE!
					  Ball_X_Motion <= Ball_X_Step;
					  
				 else 
					  Ball_Y_Motion <= Ball_Y_Motion;  // Ball is somewhere in the middle, don't bounce, just keep moving
					  
				 
				 case (keycod)
					8'h61 : begin

								Ball_X_Motion <= -1;//A
								Ball_Y_Motion<= 0;
							  end
					        
					8'h64 : begin
								
					        Ball_X_Motion <= 1;//D
							  Ball_Y_Motion <= 0;
							  end
			
					8'h77 : begin

					        Ball_Y_Motion <= 1;//S
							  Ball_X_Motion <= 0;
							 end
							  
					8'h78 : begin
					        Ball_Y_Motion <= -1;//W
							  Ball_X_Motion <= 0;
							 end	
					8'h16 : begin

								Ball_X_Motion <= -1;//A
								Ball_Y_Motion<= 0;
							  end
					        
					8'h46 : begin
								
					        Ball_X_Motion <= 1;//D
							  Ball_Y_Motion <= 0;
							  end
			
					8'h77 : begin

					        Ball_Y_Motion <= 1;//S
							  Ball_X_Motion <= 0;
							 end
							  
					8'h87 : begin
					        Ball_Y_Motion <= -1;//W
							  Ball_X_Motion <= 0;
							 end
					8'h65 : begin
								Ball_Y_Motion <=1;
								Ball_X_Motion <=1;
							  end
					8'h71 : begin
								Ball_Y_Motion <=1;
								Ball_X_Motion <=-1;
							  end
					8'h63 : begin
								Ball_Y_Motion <=-1;
								Ball_X_Motion <=1;
							  end
					8'h7A : begin
								Ball_Y_Motion <=-1;
								Ball_X_Motion <=-1;
							  end
					default: ;
			   endcase
				 
				 Ball_Y_Pos <= (Ball_Y_Pos + Ball_Y_Motion);  // Update ball position
				 Ball_X_Pos <= (Ball_X_Pos + Ball_X_Motion);
			

      
			
		end  
    end
       
    assign BallX = Ball_X_Pos;
   
    assign BallY = Ball_Y_Pos;
   
    assign BallS = Ball_Size;
    

endmodule