xilinx/xc7/tests/serdes/serdes_basys3.v

`default_nettype none

`define CLKFBOUT_MULT 2

// ============================================================================

module top
(
input  wire clk,

input  wire rst,

input  wire [7:0] sw,
output wire [9:0] led,

inout wire io
);

localparam DATA_WIDTH = `DATA_WIDTH_DEFINE;
localparam DATA_RATE =  `DATA_RATE_DEFINE;

// ============================================================================
// Clock & reset
reg [3:0] rst_sr;

initial rst_sr <= 4'hF;

wire CLK;

BUFG bufg(.I(clk), .O(CLK));

always @(posedge CLK)
    if (rst)
        rst_sr <= 4'hF;
    else
        rst_sr <= rst_sr >> 1;

wire RST = rst_sr[0];

// ============================================================================
// Clocks for ISERDES

wire PRE_BUFG_SYSCLK;
wire PRE_BUFG_CLKDIV;

wire SYSCLK;
wire CLKDIV;

wire O_LOCKED;

wire clk_fb_i;
wire clk_fb_o;

localparam DIVIDE_RATE = DATA_RATE == "SDR" ? DATA_WIDTH : DATA_WIDTH / 2;

PLLE2_ADV #(
.BANDWIDTH          ("HIGH"),
.COMPENSATION       ("ZHOLD"),

.CLKIN1_PERIOD      (10.0),  // 100MHz

.CLKFBOUT_MULT      (`CLKFBOUT_MULT),
.CLKOUT0_DIVIDE     (`CLKFBOUT_MULT * 4), // SYSCLK, 25MHz
.CLKOUT1_DIVIDE     ((`CLKFBOUT_MULT * 4) * DIVIDE_RATE), // CLKDIV, 25MHz / DIVIDE RATE

.STARTUP_WAIT       ("FALSE"),

.DIVCLK_DIVIDE      (1'd1)
)
pll
(
.CLKIN1     (CLK),
.CLKINSEL   (1),

.RST        (RST),
.PWRDWN     (0),
.LOCKED     (O_LOCKED),

.CLKFBIN    (clk_fb_i),
.CLKFBOUT   (clk_fb_o),

.CLKOUT0    (PRE_BUFG_SYSCLK),
.CLKOUT1    (PRE_BUFG_CLKDIV)
);

BUFG bufg_clk(.I(PRE_BUFG_SYSCLK), .O(SYSCLK));
BUFG bufg_clkdiv(.I(PRE_BUFG_CLKDIV), .O(CLKDIV));

// ============================================================================
// Test uints
wire [7:0] OUTPUTS;

wire [7:0] INPUTS = sw[7:0];

localparam MASK = DATA_WIDTH == 2 ? 8'b00000011 :
                  DATA_WIDTH == 3 ? 8'b00000111 :
                  DATA_WIDTH == 4 ? 8'b00001111 :
                  DATA_WIDTH == 5 ? 8'b00011111 :
                  DATA_WIDTH == 6 ? 8'b00111111 :
                  DATA_WIDTH == 7 ? 8'b01111111 :
                /*DATA_WIDTH == 8*/ 8'b11111111;

wire [7:0] MASKED_INPUTS = INPUTS & MASK;

wire I_DAT;
wire O_DAT;
wire T_DAT;

IOBUF iobuf(.I(O_DAT), .O(I_DAT), .T(T_DAT), .IO(io));

serdes_test #
(
.DATA_WIDTH   (DATA_WIDTH),
.DATA_RATE    (DATA_RATE)
)
serdes_test
(
.SYSCLK     (SYSCLK),
.CLKDIV     (CLKDIV),
.RST        (RST),

.OUTPUTS    (OUTPUTS),
.INPUTS     (MASKED_INPUTS),

.I_DAT      (I_DAT),
.O_DAT      (O_DAT),
.T_DAT      (T_DAT)
);

wire [7:0] MASKED_OUTPUTS = OUTPUTS & MASK;

// ============================================================================
// I/O connections

reg [23:0] heartbeat_cnt;

always @(posedge SYSCLK)
    heartbeat_cnt <= heartbeat_cnt + 1;


assign led[0] = heartbeat_cnt[22];
assign led[8:1] = MASKED_OUTPUTS;

endmodule