9x11_v3_16err

module LCD_CTRL(clk, reset, datain, cmd, cmd_valid, dataout, output_valid, busy);


input clk;
input reset;
input [7:0] datain;
input [2:0] cmd;
input cmd_valid;


output reg [7:0] dataout;
output reg output_valid;
output reg busy;

reg [1:0]p_state,n_state;
reg [7:0]data_buf[107:0];
reg [3:0]ox,oy,cx,cy;
reg [6:0]cnt;
reg flag ;
reg boundary;
reg loaddone;
reg IniDone1,IniDone2,IniDone3;
//reg cnting;
reg [9:0]tmp; // = 12*cy + cx;
//data = 12y+x;

parameter Initial_S = 2'b00,
             Load_Data = 2'b01,
             Zoom_Fit  = 2'b10,
             Zoom_In      = 2'b11;

parameter Left = 4'b0010 ,
             Up = 4'b0010 ,
             Right= 4'b1010 ,
             Down = 4'b0111 ;

/* State control */
always@(*)
begin
    if(reset)
        p_state <= Initial_S ;
    else
        p_state <= n_state ;
end

/* Next state logic */
always@(posedge clk)
begin
if( (cmd_valid && !busy) )
    case(cmd)
        3'b000  :
                            n_state = Load_Data;
        3'b001  :
                            n_state = Zoom_In;
        3'b010  :
                            n_state = Zoom_Fit;
        3'b011  :
            begin
                            if( p_state == Zoom_Fit )   n_state = p_state ;
                            else                               n_state = Zoom_In ;
            end
        3'b100  :
            begin
                            if( p_state == Zoom_Fit )   n_state = p_state ;
                            else                               n_state = Zoom_In ;
            end
        3'b101  :
            begin
                            if( p_state == Zoom_Fit )   n_state = p_state ;
                            else                               n_state = Zoom_In ;
            end
        3'b110  :
            begin
                            if( p_state == Zoom_Fit )   n_state = p_state ;
                            else                               n_state = Zoom_In ;
            end
        default :       ;
    endcase
else if(loaddone)
    n_state = Zoom_Fit;
end

/* Output logic with Counter */
always@(posedge clk)
begin
    case(p_state)
            Initial_S   :
                begin
                    //busy <= 0;
                    //output_valid <= 0;
                    cnt <= 0;
                    loaddone <= 0;
                    cx <= 0;
                    cy <= 0;
                    IniDone1 <= 0;
                    IniDone2 <= 0;
                    IniDone3 <= 0;
                    flag <= 0;
                end
            Load_Data   :
                begin
                    if( cnt != 0 && !IniDone1)
                        begin
                            cnt <= 0;
                            IniDone1 <= 1;
                            loaddone <= 0;
                        //  busy <= 1;
                            //output_valid <= 0;
                        end
                    else if( cnt == 107)
                        begin
                            cnt <= 0;
                            loaddone <= 1;
                            IniDone1 <= 0;
                            cy <= 4'b0001 ;
                            cx <= 4'b0001 ;
                        end
                    else if(!loaddone)
                        begin
                            IniDone1 <= 1;
                            IniDone2 <= 0;
                            IniDone3 <= 0;
                            //output_valid <= 0;
                        //  busy <= 1;
                            cnt <= cnt + 1;
                        end
                end
            Zoom_Fit        :
                begin
                    if( (cy != 4'b0001 || cx != 4'b0001) && !IniDone2)
                        begin
                            cy <= 4'b0001 ;
                            cx <= 4'b0001 ;
                        //  busy <= 1;
                            //output_valid <= 0;
                            IniDone2 <= 1;
                            flag <= 0;
                        end
                    else if( cx == 4'b1010 && cy == 4'b0111 )
                        begin
                        //  busy <= 0;
                            //output_valid <= 0;
                            //cx <= 4'b0001 ;
                            //cy <= 4'b0001 ;
                            loaddone <= 0;
                            IniDone2 <= 0;
                            flag <= 1;
                        end
                    else if( cx == 4'b1010 )
                        begin
                            cx <= 4'b0001;
                            cy <= cy + 2 ;
                        end
                    else
                        begin
                            IniDone1 <= 0;
                            IniDone2 <= 1;
                            IniDone3 <= 0;
                            //output_valid <= 1;
                        //  busy <= 1;
                            cx <= cx + 3 ;
                            flag <= 0;
                        end
                end

            Zoom_In     :
                begin
                    if( (((cy != oy - 2) || (cx != ox - 2)) && !IniDone3) || (boundary && !busy) )
                        begin
                            cy <= oy - 2 ;
                            cx <= ox - 2 ;
                        //  busy <= 1;
                            //output_valid <= 0;
                            IniDone3 <= 1;
                            flag <= 0;
                        end
                    else if( (cx == ox + 1) && (cy == oy + 1))
                        begin
                            //busy <= 0;
                            //output_valid <= 0;
                            cx <= ox - 2 ;
                            cy <= oy - 2 ;
                            //loaddone <= 0;
                            IniDone3 <= 0;
                            flag <= 1;
                        end
                    else if( cx == ox + 1 )
                        begin
                            cx <= ox - 2 ;
                            cy <= cy + 1 ;
                        end
                    else
                        begin
                            IniDone1 <= 0;
                            IniDone2 <= 0;
                            IniDone3 <= 1;
                            flag <= 0;
                        //  output_valid <= 1;
                            //busy <= 1;
                            cx <= cx + 1 ;

                        end
                end

            default     :
                begin
                    //busy <= 0;
                    //output_valid <= 0;
                end
    endcase
end
/* Boundary condition */
always@(*)
begin
    if(reset)
        boundary = 0;
    else if( (ox == Right) || (ox == Left) || (oy == Down) || (oy == Up))
        boundary = 1;
    else
        boundary = 0;
end

/* Busy and Output_valid control */
always@(*)
begin
    case(p_state)
            Initial_S   :
            begin
                            busy <= 0;
                            output_valid <= 0;
            end

            Load_Data   :
                begin
                    if( cnt != 0 && !IniDone1)
                        begin
                            busy <= 1;
                            output_valid <= 1;
                        end
                    else if(!loaddone)
                        begin
                            output_valid <= 0;
                            busy <= 1;
                        end
                end
            Zoom_Fit        :
                begin

                    //if( /*cx == 4'b1010 && cy == 4'b0111*/ flag )
                    //  begin
                    //      busy <= 0;
                    //      output_valid <= 0;
                            //cx <= 4'b0001 ;
                            //cy <= 4'b0001 ;
                    //  end
                    //else
                    if( cx == 4'b1010 && cy == 4'b0111 && flag)
                        begin
                            busy <= 0;
                            output_valid <= 0;
                            //cx <= 4'b0001 ;
                            //cy <= 4'b0001 ;
                        end
                    else if( (cy != 4'b0001 || cx != 4'b0001) && !IniDone2)
                        begin
                            busy <= 1;
                            //output_valid <= 1;
                        end
                    else
                        begin
                            output_valid <= 1;
                            busy <= 1;
                        end
                end

            Zoom_In     :
                begin
                    if( /*(cx == ox + 1) && (cy == oy + 1)*/ flag)
                        begin
                            busy <= 0;
                            output_valid <= 0;
                        end
                    else if( ((cy != oy - 2) || (cx != ox - 2)) && !IniDone3)
                        begin
                            busy <= 1;
                            //output_valid <= 1;
                        end
                    else
                        begin
                            output_valid <= 1;
                            busy <= 1;
                        end
                end

            default     :
                    begin
                        busy <= 0;
                        output_valid <= 0;
                    end
    endcase
end
/* Cmd logic and origin control*/
always@(*)
begin
    case(cmd)
        3'b000  :
                        begin
                            ox = 6;
                            oy = 5;
                        end
        3'b001  ://zoomin
                        begin
                            if(!boundary)
                            begin
                                ox = 6;
                                oy = 5;
                            end
                            else
                                ;
                        end
        3'b010  ://zoomfit
                        begin
                            ox = 6;
                            oy = 5;
                        end
        3'b011  :
                        begin
                        if( ox < Right )
                            ox = ox + 1;
                        else
                            ox = ox ;
                        end
        3'b100  :
                        begin
                        if( ox > Left )
                            ox = ox - 1;
                        else
                            ox = ox ;
                        end
        3'b101  :
                        begin
                        if( oy > Up )
                            oy = oy - 1;
                        else
                            oy = oy ;
                        end
        3'b110  :
                        begin
                        if( oy < Down )
                            oy = oy + 1 ; // oy = 3 ; // PASS
                        else
                            oy = oy ;
                        end
        /*default   :
                        begin
                            ;
                        end*/
    endcase
end



/* Data processing */
always@(*)
begin
    if(busy)
    begin
        case(n_state)
            Load_Data   :
                begin
                    data_buf[cnt] <= datain;
                end
            default     :
                begin
                    dataout <= data_buf[tmp];
                end
        endcase
    end
end
always@(*)
begin
    tmp <= 12*cy + cx;
end

endmodule