Subversion Repositories usb_fpga_2_14

/*%

   memfifo -- Connects the bi-directional high speed interface of default firmware to a FIFO built of on-board SDRAM or on-chip BRAM

   Copyright (C) 2009-2017 ZTEX GmbH.

   http://www.ztex.de

   Copyright and related rights are licensed under the Solderpad Hardware

   License, Version 0.51 (the "License"); you may not use this file except

   in compliance with the License. You may obtain a copy of the License at

       http://solderpad.org/licenses/SHL-0.51.

   Unless required by applicable law or agreed to in writing, software, hardware

   and materials distributed under this License is distributed on an "AS IS"

   BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or

   implied. See the License for the specific language governing permissions

   and limitations under the License.

%*/

/*

   Top level module: glues everything together.

*/

module memfifo (

        input ifclk_in,

        input reset,

        // debug

        output [9:0] led1,

        input SW8,

        // ez-usb

        inout [15:0] fd,

        output SLWR, SLRD,

        output SLOE, FIFOADDR0, FIFOADDR1, PKTEND,

        input FLAGA, FLAGB,

        // GPIO

        input gpio_clk, gpio_dir,

        inout gpio_dat

    );

    wire reset_usb;

    wire ifclk;

    reg reset_ifclk;

    wire [9:0] status;

    wire [3:0] if_status;

    wire [3:0] mode;

    // input fifo

    reg [31:0] DI;

    wire FULL, WRERR, USB_DO_valid;

    reg WREN, wrerr_buf;

    wire [15:0] USB_DO;

    reg [31:0] in_data;

    reg [3:0] wr_cnt;

    reg [6:0] test_cnt;

    reg [13:0] test_cs;

    reg in_valid;

    wire test_sync;

    reg [1:0] clk_div;

    reg DI_run;

    // output fifo

    wire [31:0] DO;

    wire EMPTY, RDERR, USB_DI_ready;

    reg RDEN, rderr_buf, USB_DI_valid;

    reg [31:0] rd_buf;

    reg rd_cnt;

    bram_fifo bram_fifo_inst (

        .reset(reset || reset_usb),

        // input fifo interface

        .DI(DI),                        // must be hold while FULL is asserted

        .FULL(FULL),                    // 1-bit output: Full flag

        .WRERR(WRERR),                  // 1-bit output: Write error

        .WREN(WREN),                    // 1-bit input: Write enable

        .WRCLK(ifclk),                  // 1-bit input: Rising edge write clock.

        // output fifo interface

        .DO(DO),

        .EMPTY(EMPTY),                  // 1-bit output: Empty flag

        .RDERR(RDERR),                  // 1-bit output: Read error

        .RDCLK(ifclk),                  // 1-bit input: Read clock

        .RDEN(RDEN)                     // 1-bit input: Read enable

        // for debugging

    );

    ezusb_gpio gpio_inst (

        .clk(ifclk),                    // system clock, minimum frequency is 24 MHz

        // hardware pins

        .gpio_clk(gpio_clk),            // data clock; data sent on both edges

        .gpio_dir(gpio_dir),            // 1: output, 0->1 transition latches input data and starts writing

        .gpio_dat(gpio_dat),

        // interface

        .in(mode),

        .out(4'd0)                      // wired or: GPIO's not used for output should be 0

    );

    ezusb_io #(

        .OUTEP(2),                      // EP for FPGA -> EZ-USB transfers

        .INEP(6),                       // EP for EZ-USB -> FPGA transfers 

        .TARGET("A7")                   // "A4" for Artix 7

    ) ezusb_io_inst (

        .ifclk(ifclk),

        .reset(reset),                  // asynchronous reset input

        .reset_out(reset_usb),          // synchronous reset output

        // pins

        .ifclk_in(ifclk_in),

        .fd(fd),

        .SLWR(SLWR),

        .SLRD(SLRD),

        .SLOE(SLOE),

        .PKTEND(PKTEND),

        .FIFOADDR({FIFOADDR1, FIFOADDR0}),

        .EMPTY_FLAG(FLAGA),

        .FULL_FLAG(FLAGB),

        // signals for FPGA -> EZ-USB transfer

        .DI(rd_buf[15:0]),               // data written to EZ-USB

        .DI_valid(USB_DI_valid),        // 1 indicates data valid; DI and DI_valid must be hold if DI_ready is 0

        .DI_ready(USB_DI_ready),        // 1 if new data are accepted

        .DI_enable(1'b1),               // setting to 0 disables FPGA -> EZ-USB transfers

        .pktend_arm(mode[2]),           // 0->1 transition enables the manual PKTEND mechanism:

                                        // PKTEND is asserted as soon output becomes idle

                                        // recommended procedure for accurate packet transfers:

                                        //   * DI_validgoes low after last data of package

                                        //   * monitor PKTEND and hold DI_valid until PKTEND is asserted (PKTEND = 0)

        .pktend_timeout(16'd366),       // automatic PKTEN assertation after pktend_timeout*65536 (approx. 0.5s) clocks of no

                                        // output data. Setting to 0 disables this feature.

        // signals for EZ-USB -> FPGA transfer

        .DO(USB_DO),                    // data read from EZ-USB

        .DO_valid(USB_DO_valid),        // 1 indicated valid data

        .DO_ready((mode[1:0]==2'd0) && !reset_ifclk && !FULL),   // setting to 1 enables writing new data to DO in next clock; DO and DO_valid are hold if DO_ready is 0

        // debug output

        .status(if_status)

    );

    // debug board LEDs    

//    assign led1 =  { EMPTY, FULL, wrerr_buf, rderr_buf, if_status, FLAGB, FLAGA };

    assign led1 =  { EMPTY, FULL, mode[1:0], if_status, FLAGB, FLAGA };

    assign test_sync = wr_cnt[0] || (wr_cnt == 4'd14);

    always @ (posedge ifclk)

    begin

        reset_ifclk <= reset || reset_usb;

        if ( reset_ifclk )

        begin

            rderr_buf <= 1'b0;

            wrerr_buf <= 1'b0;

        end else

        begin

            rderr_buf <= rderr_buf || RDERR;

            wrerr_buf <= wrerr_buf || WRERR;

        end

        // FPGA -> EZ-USB FIFO

        DI_run <= !mode[2];

        if ( reset_ifclk )

        begin

            rd_cnt <= 1'd0;

            USB_DI_valid <= 1'd0;

        end else if ( USB_DI_ready )

        begin

            USB_DI_valid <= !EMPTY && DI_run;

            if ( !EMPTY && DI_run )

            begin

                if ( rd_cnt == 1'd0 )

                begin

                    rd_buf <= DO;

                end else

                begin

                    rd_buf[15:0] <= rd_buf[31:16];

                end

                rd_cnt <= rd_cnt + 1'd1;

            end

        end

        RDEN <= !reset_ifclk && USB_DI_ready && !EMPTY && (rd_cnt==1'd0) && DI_run;

        // data source

        if ( reset_ifclk )

        begin

            in_data <= 31'd0;

            in_valid <= 1'b0;

            wr_cnt <= 4'd0;

            test_cnt <= 7'd0;

            test_cs <= 12'd47;

            WREN <= 1'b0;

            clk_div <= 2'd3;

            DI <= 32'h05040302;

        end else if ( !FULL )

        begin

            if ( in_valid ) DI <= in_data;

//          DI <= DI + 32'h03030303;

            if ( mode[1:0] == 2'd0 )             // input from USB

            begin

                if ( USB_DO_valid )

                begin

                    in_data <= { USB_DO, in_data[31:16] };

                    in_valid <= wr_cnt[0];

                    wr_cnt <= wr_cnt + 4'd1;

                end else

                begin

                    in_valid <= 1'b0;

                end

            end else if ( clk_div == 2'd0 )     // test data generator 

            begin

                if ( wr_cnt == 4'd15 )

                begin

                    test_cs <= 12'd47;

                    in_data[30:24] <= test_cs[6:0] ^ test_cs[13:7];

                end else

                begin

                    test_cnt <= test_cnt + 7'd111;

                    test_cs <= test_cs + { test_sync, test_cnt };

                    in_data[30:24] <= test_cnt;

                end

                in_data[31] <= test_sync;

                in_data[23:0] <= in_data[31:8];

                in_valid <= wr_cnt[1:0] == 2'd3;

                wr_cnt <= wr_cnt + 4'd1;

            end else

            begin

                in_valid <= 1'b0;

            end

            if ( (mode[1:0]==2'd1) || ((mode[1:0]==2'd3) && SW8 ) )

            begin

                clk_div <= 2'd0;        // data rate: 48 MByte/s

            end else

            begin

                clk_div <= clk_div + 2'd1;      // data rate: 12 MByte/s

            end

        end

        WREN <= !reset_ifclk && in_valid && !FULL;

//      WREN <= !reset_ifclk && !FULL;

    end

endmodule