DC EMU New SD Driver (OzOnE)

    case (state)
            // *** INIT SD Card / Driver ***
            0: begin
                sd_rst_i <= 1'b0;                   // Bring the SD Card driver out of reset (active HIGH)!

                sd_address_i <= `TRANS_TYPE_REG;    // Select the SD Transmission Type reg.
                sd_data_i <= `INIT_SD;              // Initialize the SD Card.
                sd_we_i <= 1'b1;                    // WRITE (1).
                sd_strobe_i <= 1'b1;                // Select the SD Driver.

                state <= 10'd1;
            end

            1: if (sd_ack_o) begin                  // Wait for SD Driver ack (for previous WRITE).
                sd_address_i <= `TRANS_CTRL_REG;    // Select the SD Transmission Control reg.
                sd_data_i <= `TRANS_START;          // Initialize the SD Card.
                sd_we_i <= 1'b1;                    // WRITE (1).
//              sd_strobe_i <= 1'b1;                // Select the SD Driver. (still set from previous state!)

                state <= 10'd2;
            end

            2: if (sd_ack_o) begin                  // Wait for SD Driver ack (for previous WRITE).
                sd_address_i <= `TRANS_STS_REG;     // Read the SD Transmission Status reg.
                sd_we_i <= 1'b0;                    // READ (0).
//              sd_strobe_i <= 1'b1;                // Select the SD Driver. (still set from previous state!)

                state <= 10'd3;
            end

            3: if (sd_ack_o && !(sd_data_o == `TRANS_BUSY)) begin   // Wait for SD Driver ack, and check if NOT busy...
                    sd_address_i <= `TRANS_ERROR_REG;   // Read the SD Transmission Error reg.
                    sd_we_i <= 1'b0;                    // READ (0).
//                  sd_strobe_i <= 1'b1;                // Select the SD Driver. (still set from previous state!)
                    state <= 10'd4;
                end

            4: if (sd_ack_o) begin                      // Wait for SD Driver ack (for previous READ).
                if (sd_data_o[1:0] == `INIT_NO_ERROR) begin
                    error <= 1'b0;
                    sd_strobe_i <= 1'b0;                // De-select the SD Driver.
                    state <= 5;
                end
                else
                    error <= 1'b1;
            end

            // *** IDLE State (wait for "trig_block_read")... ***
            5: begin
                block_read_done <= 1'b0;

                if (trig_block_read) begin
                gd_bytecount <= gd_sector_count * 2048; // 2048 Bytes per GD sector.

//              gd_bytecount <= 7056000;                // TESTING audio streaming !! (20 seconds worth at 44100Hz).

                sd_bytecount <= 32'd0;
                dc_bytecount <= 32'd0;

//              Host_ADDR <= 24'h000000;        // Set SDRAM start Address.

                SRAM_ADDR_REG <= 19'h000000;    // Set SRAM start Address.
                SRAM_OE_n <= 1'b1;              // De-assert SRAM Output Enable (allow writing)!

//              if (CCS)    // This should be HIGH if SD Card is SDHC.
//                  sd_sector_addr <= (gd_start_sector - 45150) * 4;    // SDHC cards use 512-byte SECTOR addressing - Need to multiply the GD sector offset by 4.
//              else
                    sd_sector_addr <= (gd_start_sector - 45150) * 2048; // Low-density SD Cards use BYTE addressing - Need to multiply the GD sector offset by 2048.

                sd_address_i <= `SD_ADDR_31_24_REG;     // Select the SD Sector Address reg (bits 31:24).
                sd_data_i <= sd_sector_addr[31:24];     // Set the address bits.
                sd_we_i <= 1'b1;                        // WRITE (1).
                sd_strobe_i <= 1'b1;                    // Select the SD Driver.

                state <= 10'd6;

                end
            end

            6: if (sd_ack_o) begin                      // Wait for SD Driver ack (for previous WRITE).
                sd_address_i <= `SD_ADDR_23_16_REG;     // Select the SD Sector Address reg (bits 23:16).
                sd_data_i <= sd_sector_addr[23:16];     // Set the address bits.
                sd_we_i <= 1'b1;                        // WRITE (1).
                sd_strobe_i <= 1'b1;                    // Select the SD Driver.

                state <= 10'd7;
//              state <= 10'd12;                // TESTING audio streaming !!
            end

            7: if (sd_ack_o) begin                      // Wait for SD Driver ack (for previous WRITE).
                sd_address_i <= `SD_ADDR_15_8_REG;      // Select the SD Sector Address reg (bits 15:8).
                sd_data_i <= sd_sector_addr[15:8];      // Set the address bits.
                sd_we_i <= 1'b1;                        // WRITE (1).
                sd_strobe_i <= 1'b1;                    // Select the SD Driver.

                state <= 10'd8;
            end

            8: if (sd_ack_o) begin                      // Wait for SD Driver ack (for previous WRITE).
                sd_address_i <= `SD_ADDR_7_0_REG;       // Select the SD Sector Address reg (bits 7:0).
                sd_data_i <= sd_sector_addr[7:0];       // Set the address bits.
                sd_we_i <= 1'b81;                       // WRITE (1).
                sd_strobe_i <= 1'b1;                    // Select the SD Driver.

                state <= 10'd9;
            end

            9: if (sd_ack_o) begin                      // Wait for SD Driver ack (for previous WRITE).
                sd_address_i <= `SD_ADDR_7_0_REG;       // Select the SD Sector Address reg (bits 7:0).
                sd_data_i <= sd_sector_addr[7:0];       // Set the address bits.
                sd_we_i <= 1'b1;                        // WRITE (1).
                sd_strobe_i <= 1'b1;                    // Select the SD Driver.

                state <= 10'd10;
            end

            10: if (sd_ack_o) begin                     // Wait for SD Driver ack (for previous WRITE).
                sd_address_i <= `TRANS_TYPE_REG;        // Select the SD Transmission Type reg.
                sd_data_i <= `RW_READ_SD_BLOCK;         // "Block Read" command.
                sd_we_i <= 1'b1;                        // WRITE (1).
                sd_strobe_i <= 1'b1;                    // Select the SD Driver.

                state <= 10'd11;
            end

            11: if (sd_ack_o) begin                     // Wait for SD Driver ack (for previous WRITE).
                sd_address_i <= `TRANS_CTRL_REG;        // Select the SD Transmission Control reg.
                sd_data_i <= `TRANS_START;              // Transmit the command.
                sd_we_i <= 1'b1;                        // WRITE (1).
                sd_strobe_i <= 1'b1;                    // Select the SD Driver.

                state <= 10'd12;
            end

            12: if (sd_ack_o && sd_data_o !== `TRANS_BUSY) begin    // Wait for SD Driver ack, and check if NOT busy...
                    sd_address_i <= `TRANS_ERROR_REG;   // Read the SD Transmission Error reg.
                    sd_we_i <= 1'b0;                    // READ (0).
//                  sd_strobe_i <= 1'b1;                // Select the SD Driver. (still set from previous state!)
                    state <= 10'd13;
                end

            13: if (sd_ack_o) begin                 // Wait for SD Driver ack (for previous READ), and check if NOT busy...

                if (sd_data_o[3:2] == `READ_NO_ERROR) begin
                    error <= 1'b0;
                    sd_strobe_i <= 1'b0;                // De-select the SD Driver.
                    state <= 14;
                end
                else
                    error <= 1'b1;
            end

            14: begin

            end

// Grab the MSB Byte from SD Card...