module fpga (
    /*
     * Clock: 100MHz
     * Reset: Push button, active low
     */
    input  wire       clk,
    input  wire       reset_n,

    /*
     * GPIO
     */
    input  wire       btnu,
    input  wire       btnl,
    input  wire       btnd,
    input  wire       btnr,
    input  wire       btnc,
    input  wire [7:0] sw,
    output wire [7:0] led,

    /*
     * I2C
     */
    inout  wire       i2c_scl,
    inout  wire       i2c_sda,

    /*
     * Ethernet: 1000BASE-T RGMII
     */
    input  wire       phy_rx_clk,
    input  wire [3:0] phy_rxd,
    input  wire       phy_rx_ctl,
    output wire       phy_tx_clk,
    output wire [3:0] phy_txd,
    output wire       phy_tx_ctl,
    output wire       phy_reset_n,
    input  wire       phy_int_n,
    input  wire       phy_pme_n,

    /*
     * UART: 115200 bps, 8N1
     */
    input  wire       uart_rxd,
    output wire       uart_txd
);

// Clock and reset

wire clk_ibufg;
wire clk_bufg;
wire clk_mmcm_out;

// Internal 125 MHz clock
wire clk_int;
wire rst_int;   

wire mmcm_rst = ~reset_n;
wire mmcm_locked;
wire mmcm_clkfb;

IBUFG
clk_ibufg_inst(
    .I(clk),
    .O(clk_ibufg)
);

wire clk90_mmcm_out;
wire clk90_int;

wire clk_200_mmcm_out;
wire clk_200_int;

// MMCM instance
// 100 MHz in, 125 MHz out
// PFD range: 10 MHz to 550 MHz
// VCO range: 600 MHz to 1200 MHz
// M = 10, D = 1 sets Fvco = 1000 MHz (in range)
// Divide by 8 to get output frequency of 125 MHz
// Need two 125 MHz outputs with 90 degree offset
// Also need 200 MHz out for IODELAY
// 1000 / 5 = 200 MHz
MMCME2_BASE #(
    .BANDWIDTH("OPTIMIZED"),
    .CLKOUT0_DIVIDE_F(8),
    .CLKOUT0_DUTY_CYCLE(0.5),
    .CLKOUT0_PHASE(0),
    .CLKOUT1_DIVIDE(8),
    .CLKOUT1_DUTY_CYCLE(0.5),
    .CLKOUT1_PHASE(90),
    .CLKOUT2_DIVIDE(5),
    .CLKOUT2_DUTY_CYCLE(0.5),
    .CLKOUT2_PHASE(0),
    .CLKOUT3_DIVIDE(1),
    .CLKOUT3_DUTY_CYCLE(0.5),
    .CLKOUT3_PHASE(0),
    .CLKOUT4_DIVIDE(1),
    .CLKOUT4_DUTY_CYCLE(0.5),
    .CLKOUT4_PHASE(0),
    .CLKOUT5_DIVIDE(1),
    .CLKOUT5_DUTY_CYCLE(0.5),
    .CLKOUT5_PHASE(0),
    .CLKOUT6_DIVIDE(1),
    .CLKOUT6_DUTY_CYCLE(0.5),
    .CLKOUT6_PHASE(0),
    .CLKFBOUT_MULT_F(10),
    .CLKFBOUT_PHASE(0),
    .DIVCLK_DIVIDE(1),
    .REF_JITTER1(0.010),
    .CLKIN1_PERIOD(10.0),
    .STARTUP_WAIT("FALSE"),
    .CLKOUT4_CASCADE("FALSE")
)
clk_mmcm_inst (
    .CLKIN1(clk_ibufg),
    .CLKFBIN(mmcm_clkfb),
    .RST(mmcm_rst),
    .PWRDWN(1'b0),
    .CLKOUT0(clk_mmcm_out),
    .CLKOUT0B(),
    .CLKOUT1(clk90_mmcm_out),
    .CLKOUT1B(),
    .CLKOUT2(clk_200_mmcm_out),
    .CLKOUT2B(),
    .CLKOUT3(),
    .CLKOUT3B(),
    .CLKOUT4(),
    .CLKOUT5(),
    .CLKOUT6(),
    .CLKFBOUT(mmcm_clkfb),
    .CLKFBOUTB(),
    .LOCKED(mmcm_locked)
);

BUFG
clk_bufg_inst (
    .I(clk_mmcm_out),
    .O(clk_int)
);

BUFG
clk90_bufg_inst (
    .I(clk90_mmcm_out),
    .O(clk90_int)
);

BUFG
clk_200_bufg_inst (
    .I(clk_200_mmcm_out),
    .O(clk_200_int)
);

sync_reset #(
    .N(4)
)
sync_reset_inst (
    .clk(clk_int),
    .rst(~mmcm_locked),
    .out(rst_int)
);

// GPIO
wire btnu_int;
wire btnl_int;
wire btnd_int;
wire btnr_int;
wire btnc_int;
wire [7:0] sw_int;

debounce_switch #(
    .WIDTH(13),
    .N(4),
    .RATE(125000)
)
debounce_switch_inst (
    .clk(clk_int),
    .rst(rst_int),
    .in({btnu,
        btnl,
        btnd,
        btnr,
        btnc,
        sw}),
    .out({btnu_int,
        btnl_int,
        btnd_int,
        btnr_int,
        btnc_int,
        sw_int})
);

sync_signal #(
    .WIDTH(1),
    .N(2)
)
sync_signal_inst (
    .clk(clk_int),
    .in({uart_rxd}),
    .out({uart_rxd_int})
);

assign i2c_scl_i = i2c_scl;
assign i2c_scl = i2c_scl_t ? 1'bz : i2c_scl_o;
assign i2c_sda_i = i2c_sda;
assign i2c_sda = i2c_sda_t ? 1'bz : i2c_sda_o;

// IODELAY elements for RGMII interface to PHY
wire [3:0] phy_rxd_delay;
wire       phy_rx_ctl_delay;

IDELAYCTRL
idelayctrl_inst
(
    .REFCLK(clk_200_int),
    .RST(rst_int),
    .RDY()
);

IDELAYE2 #(
    .IDELAY_TYPE("FIXED")
)
phy_rxd_idelay_0
(
    .IDATAIN(phy_rxd[0]),
    .DATAOUT(phy_rxd_delay[0]),
    .DATAIN(1'b0),
    .C(1'b0),
    .CE(1'b0),
    .INC(1'b0),
    .CINVCTRL(1'b0),
    .CNTVALUEIN(5'd0),
    .CNTVALUEOUT(),
    .LD(1'b0),
    .LDPIPEEN(1'b0),
    .REGRST(1'b0)
);

IDELAYE2 #(
    .IDELAY_TYPE("FIXED")
)
phy_rxd_idelay_1
(
    .IDATAIN(phy_rxd[1]),
    .DATAOUT(phy_rxd_delay[1]),
    .DATAIN(1'b0),
    .C(1'b0),
    .CE(1'b0),
    .INC(1'b0),
    .CINVCTRL(1'b0),
    .CNTVALUEIN(5'd0),
    .CNTVALUEOUT(),
    .LD(1'b0),
    .LDPIPEEN(1'b0),
    .REGRST(1'b0)
);

IDELAYE2 #(
    .IDELAY_TYPE("FIXED")
)
phy_rxd_idelay_2
(
    .IDATAIN(phy_rxd[2]),
    .DATAOUT(phy_rxd_delay[2]),
    .DATAIN(1'b0),
    .C(1'b0),
    .CE(1'b0),
    .INC(1'b0),
    .CINVCTRL(1'b0),
    .CNTVALUEIN(5'd0),
    .CNTVALUEOUT(),
    .LD(1'b0),
    .LDPIPEEN(1'b0),
    .REGRST(1'b0)
);

IDELAYE2 #(
    .IDELAY_TYPE("FIXED")
)
phy_rxd_idelay_3
(
    .IDATAIN(phy_rxd[3]),
    .DATAOUT(phy_rxd_delay[3]),
    .DATAIN(1'b0),
    .C(1'b0),
    .CE(1'b0),
    .INC(1'b0),
    .CINVCTRL(1'b0),
    .CNTVALUEIN(5'd0),
    .CNTVALUEOUT(),
    .LD(1'b0),
    .LDPIPEEN(1'b0),
    .REGRST(1'b0)
);

IDELAYE2 #(
    .IDELAY_TYPE("FIXED")
)
phy_rx_ctl_idelay
(
    .IDATAIN(phy_rx_ctl),
    .DATAOUT(phy_rx_ctl_delay),
    .DATAIN(1'b0),
    .C(1'b0),
    .CE(1'b0),
    .INC(1'b0),
    .CINVCTRL(1'b0),
    .CNTVALUEIN(5'd0),
    .CNTVALUEOUT(),
    .LD(1'b0),
    .LDPIPEEN(1'b0),
    .REGRST(1'b0)
);

fpga_core
core_inst (
    /*
     * Clock: 125MHz
     * Synchronous reset
     */
    .clk(clk_int),
    .clk90(clk90_int),
    .rst(rst_int),
    /*
     * GPIO
     */
    .btnu(btnu_int),
    .btnl(btnl_int),
    .btnd(btnd_int),
    .btnr(btnr_int),
    .btnc(btnc_int),
    .sw(sw_int),
    .led(led),
    /*
     * I2C
     */
    .i2c_scl_i(i2c_scl_i),
    .i2c_scl_o(i2c_scl_o),
    .i2c_scl_t(i2c_scl_t),
    .i2c_sda_i(i2c_sda_i),
    .i2c_sda_o(i2c_sda_o),
    .i2c_sda_t(i2c_sda_t),
    /*
     * Ethernet: 1000BASE-T RGMII
     */
    .phy_rx_clk(phy_rx_clk),
    .phy_rxd(phy_rxd_delay),
    .phy_rx_ctl(phy_rx_ctl_delay),
    .phy_tx_clk(phy_tx_clk),
    .phy_txd(phy_txd),
    .phy_tx_ctl(phy_tx_ctl),
    .phy_reset_n(phy_reset_n),
    .phy_int_n(phy_int_n),
    .phy_pme_n(phy_pme_n),
    /*
     * UART: 115200 bps, 8N1
     */
    .uart_rxd(uart_rxd_int),
    .uart_txd(uart_txd)
);

endmodule