top.v

module top (
    input  wire        clk,         //100 MHZ      
    
    // SCCB 
    output wire        sio_c,      // clock
    inout  wire        sio_d,      // data

    // Camera outputs
    input  wire        vsync,      
    input  wire        href,      
    input  wire        pclk,  
    input  wire [7:0]  data,      // D0-D7

    // Control signals
    output wire        xclk,       // Camera clk 25 MHZ
    output wire        reset_cam,  // Camera reset (active low)
    output wire        pwdn,        // Power down control (active low)
    //output wire [7:0]  read_data,

    //led
    output wire [3:0]  led,
    input  wire [3:0]  btn
);

assign pwdn      = 1'b0; 
reg       clk_div_xclk = 0;
reg       clk25MHZ     = 0;
wire rst = btn[0];
assign reset_cam = rst;

always @(posedge clk) begin
    clk_div_xclk <= clk_div_xclk + 1;
    if (clk_div_xclk == 1) begin
        clk_div_xclk <= 0;
        clk25MHZ     <= ~clk25MHZ;
    end
end
assign xclk  = clk25MHZ;

localparam OV7670 = 8'h43;
wire rw_enable;
wire rw;
wire finished;

wire [7:0] data1;
wire [7:0] data2;
wire [2:0] i2ch_state;
wire [3:0] i2c_state;
wire       i2c_wire;
reg        rw_mode = 0;

i2c_handler I2C_HANDLER (
    .clk(clk),
    .rst(rst),
    .rw_enable(rw_enable),
    .rw(rw),
    .finished(finished),
    .rw_mode(rw_mode),
    .data1(data1), 
    .data2(data2),
    .state_out(i2ch_state)
);

wire [7:0] read_data;
reg  [7:0] read_data_stored;
i2c_unit I2C (
    .clk(clk),
    .rst(rst),
    .rw_enable(rw_enable),
    .rw(rw),
    .device(OV7670),
    .finished(finished),
    .data1(data1), 
    .data2(data2),
    .read_data(read_data),
    
    .i2c_wire_out(i2c_wire),
    .i2c_wire_in(sio_d),
    .scl(sio_c),
    .state_out(i2c_state)
 );
assign sio_d = i2c_wire ? 1'bz : 1'b0;


reg [24:0] counter = 0;
reg [3:0] led_reg = 0;
reg       handler_display = 0;
always @(posedge clk) begin
    if(rst)
        rw_mode <= 0;
    if(read_data != 8'b00000000 && finished)
        read_data_stored <= read_data;
    if (btn[1]) 
        led_reg <= i2c_state;
    else if (btn[2]) begin
        rw_mode <= 1;
    end 
    else if (btn[3]) begin
        led_reg <= read_data_stored;
    end
    else begin
        led_reg <= i2ch_state;
    end 
end

assign led = led_reg;

endmodule