ISP/Crop/crop.v

module crop #(
    parameter IN_WIDTH = 1936 - 2,
    parameter IN_HEIGHT = 1088 - 2,
    parameter OFFSET_X = 8,
    parameter OFFSET_Y = 4,
    parameter OUT_WIDTH = 640,
    parameter OUT_HEIGHT = 480,
    parameter COLOR_DEPTH = 8
) (
    input clk,
    input reset,

    input in_en,
    output in_que,
    input [3 * COLOR_DEPTH - 1:0] data_in,

    output out_en,
    input out_que,
    output reg [3 * COLOR_DEPTH - 1:0] data_out
);
    wire fifo_full, fifo_empty;
    reg [11:0] cnt_x, cnt_y;
    reg fifo_en;

    async_fifo #(
        .DSIZE(3 * COLOR_DEPTH),
        .ASIZE(128)
    ) fifo_image (
        .wclk(clk),
        .wrst_n(reset),
        .rclk(clk),
        .rrst_n(reset),

        .winc(fifo_en),
        .wdata(data_in),
        .wfull(fifo_full),
        .awfull(),

        .rinc(out_en),
        .rdata(data_out),
        .rempty(fifo_empty),
        .arempty()
    );

    assign in_que = !fifo_full;
    assign out_en = (out_que && !fifo_empty) ? 1 : 0;

    always @(posedge clk or posedge reset) begin
        if (reset) begin
            fifo_en <= 0;
            cnt_x <= 0;
            cnt_y <= 0;

        end
        else begin
            if (in_en) begin

                if (OFFSET_Y <= cnt_y && cnt_y < (OFFSET_Y + OUT_HEIGHT)) begin
                    if (OFFSET_X <= cnt_x && cnt_x < (OFFSET_X + OUT_WIDTH)) begin
                        fifo_en <= 1;
                    end 
                    else begin
                        fifo_en <= 0;
                    end
                end
                else begin
                    fifo_en <= 0;
                end

                cnt_x <= cnt_x + 1;
                if (cnt_x >= (OFFSET_X + OUT_WIDTH)) begin
                    cnt_x <= 0;
                    if (cnt_y >= (OFFSET_Y + OUT_HEIGHT)) begin
                        cnt_y <= 0;
                    end
                    else begin
                        cnt_y <= cnt_y + 1;
                    end
                end
            end
        end
    end
    
endmodule