verilog/rtl/softshell/third_party/tinyfpga_bx_usbserial/usb/usb_uart_i40.v

/*
   usb_uart_i40

  Simple wrapper around the usb_uart which incorporates the Pin driver logic
  so this doesn't clutter the top level circuit

  The layer above has to assert the Host Pull Up line

  ----------------------------------------------------
  usb_uart_i40 u_u_i40 (
    .clk_48mhz  (clk_48mhz),
    .reset      (reset),

    // pins
    .pin_usb_p( pin_usb_p ),
    .pin_usb_n( pin_usb_n ),

    // uart pipeline in
    .uart_in_data( uart_in_data ),
    .uart_in_valid( uart_in_valid ),
    .uart_in_ready( uart_in_ready ),

    // uart pipeline out
    .uart_out_data( uart_out_data ),
    .uart_out_valid( uart_out_valid ),
    .uart_out_ready( uart_out_ready ),
  );

*/

module usb_uart (
  input  clk_48mhz,
  input reset,

  // USB pins
  inout  pin_usb_p,
  inout  pin_usb_n,

  // uart pipeline in (out of the device, into the host)
  input [7:0] uart_in_data,
  input       uart_in_valid,
  output      uart_in_ready,

  // uart pipeline out (into the device, out of the host)
  output [7:0] uart_out_data,
  output       uart_out_valid,
  input        uart_out_ready,

  output [11:0] debug
);

    wire usb_p_tx;
    wire usb_n_tx;
    wire usb_p_rx;
    wire usb_n_rx;
    wire usb_tx_en;

    //wire [3:0] debug;

    usb_uart_core uart (
        .clk_48mhz  (clk_48mhz),
        .reset      (reset),

        // pins - these must be connected properly to the outside world.  See below.
        .usb_p_tx(usb_p_tx),
        .usb_n_tx(usb_n_tx),
        .usb_p_rx(usb_p_rx),
        .usb_n_rx(usb_n_rx),
        .usb_tx_en(usb_tx_en),

        // uart pipeline in
        .uart_in_data( uart_in_data ),
        .uart_in_valid( uart_in_valid ),
        .uart_in_ready( uart_in_ready ),

        // uart pipeline out
        .uart_out_data( uart_out_data ),
        .uart_out_valid( uart_out_valid ),
        .uart_out_ready( uart_out_ready ),

        .debug( debug )
    );

    wire usb_p_in;
    wire usb_n_in;

    assign usb_p_rx = usb_tx_en ? 1'b1 : usb_p_in;
    assign usb_n_rx = usb_tx_en ? 1'b0 : usb_n_in;

    SB_IO #(
        .PIN_TYPE(6'b 1010_01), // PIN_OUTPUT_TRISTATE - PIN_INPUT
        .PULLUP(1'b 0)
    ) iobuf_usbp (
        .PACKAGE_PIN(pin_usb_p),
        .OUTPUT_ENABLE(usb_tx_en),
        .D_OUT_0(usb_p_tx),
        .D_IN_0(usb_p_in)
    );

    SB_IO #(
        .PIN_TYPE(6'b 1010_01), // PIN_OUTPUT_TRISTATE - PIN_INPUT
        .PULLUP(1'b 0)
    ) iobuf_usbn (
        .PACKAGE_PIN(pin_usb_n),
        .OUTPUT_ENABLE(usb_tx_en),
        .D_OUT_0(usb_n_tx),
        .D_IN_0(usb_n_in)
    );

endmodule