SummerCart64/fw/rtl/memory/embedded_flash.v

module memory_embedded_flash (
    input i_clk,
    input i_reset,

    input i_request,
    output reg o_busy,
    output o_ack,
    input [18:0] i_address,
    output reg [31:0] o_data
);

    localparam [18:0] ONCHIP_FLASH_END = 19'h059FF;

    wire w_onchip_flash_in_address_range = i_address <= ONCHIP_FLASH_END;

    reg r_dummy_ack;

    always @(posedge i_clk) begin
        r_dummy_ack <= i_request && !w_onchip_flash_in_address_range;
    end

    reg r_onchip_flash_request;
    wire w_onchip_flash_busy;
    wire w_onchip_flash_ack;
    wire [31:0] w_onchip_flash_o_data;

    assign o_ack = r_dummy_ack || w_onchip_flash_ack;

    always @(*) begin
        r_onchip_flash_request = 1'b0;
        o_busy = 1'b0;
        o_data = 32'h0000_0000;
        if (w_onchip_flash_in_address_range) begin
            r_onchip_flash_request = i_request;
            o_busy = w_onchip_flash_busy;
            o_data = {
                w_onchip_flash_o_data[7:0],
                w_onchip_flash_o_data[15:8],
                w_onchip_flash_o_data[23:16],
                w_onchip_flash_o_data[31:24],
            };
        end
    end

    onchip_flash onchip_flash_inst (
        .clock(i_clk),
        .reset_n(~i_reset),
        .avmm_data_addr(i_address),
        .avmm_data_read(r_onchip_flash_request),
        .avmm_data_readdata(w_onchip_flash_o_data),
        .avmm_data_waitrequest(w_onchip_flash_busy),
        .avmm_data_readdatavalid(w_onchip_flash_ack),
        .avmm_data_burstcount(2'd1)
    );

endmodule