Files
PLFM_RADAR/9_Firmware/9_2_FPGA/ad9484_interface_400m.v
T
2026-03-09 00:17:39 +00:00

98 lines
2.7 KiB
Verilog

module ad9484_interface_400m (
// ADC Physical Interface (LVDS)
input wire [7:0] adc_d_p, // ADC Data P
input wire [7:0] adc_d_n, // ADC Data N
input wire adc_dco_p, // Data Clock Output P (400MHz)
input wire adc_dco_n, // Data Clock Output N (400MHz)
// System Interface
input wire sys_clk, // 100MHz system clock (for control only)
input wire reset_n,
// Output at 400MHz domain
output wire [7:0] adc_data_400m, // ADC data at 400MHz
output wire adc_data_valid_400m // Valid at 400MHz
);
// LVDS to single-ended conversion
wire [7:0] adc_data;
wire adc_dco;
// IBUFDS for each data bit
genvar i;
generate
for (i = 0; i < 8; i = i + 1) begin : data_buffers
IBUFDS #(
.DIFF_TERM("TRUE"),
.IOSTANDARD("LVDS_25")
) ibufds_data (
.O(adc_data[i]),
.I(adc_d_p[i]),
.IB(adc_d_n[i])
);
end
endgenerate
// IBUFDS for DCO
IBUFDS #(
.DIFF_TERM("TRUE"),
.IOSTANDARD("LVDS_25")
) ibufds_dco (
.O(adc_dco),
.I(adc_dco_p),
.IB(adc_dco_n)
);
// IDDR for capturing DDR data
wire [7:0] adc_data_rise; // Data on rising edge
wire [7:0] adc_data_fall; // Data on falling edge
genvar j;
generate
for (j = 0; j < 8; j = j + 1) begin : iddr_gen
IDDR #(
.DDR_CLK_EDGE("SAME_EDGE_PIPELINED"),
.INIT_Q1(1'b0),
.INIT_Q2(1'b0),
.SRTYPE("SYNC")
) iddr_inst (
.Q1(adc_data_rise[j]), // Rising edge data
.Q2(adc_data_fall[j]), // Falling edge data
.C(adc_dco), // 400MHz DCO
.CE(1'b1),
.D(adc_data[j]),
.R(1'b0),
.S(1'b0)
);
end
endgenerate
// Combine rising and falling edge data to get 400MSPS stream
reg [7:0] adc_data_400m_reg;
reg adc_data_valid_400m_reg;
reg dco_phase;
always @(posedge adc_dco or negedge reset_n) begin
if (!reset_n) begin
adc_data_400m_reg <= 8'b0;
adc_data_valid_400m_reg <= 1'b0;
dco_phase <= 1'b0;
end else begin
dco_phase <= ~dco_phase;
if (dco_phase) begin
// Output falling edge data (completes the 400MSPS stream)
adc_data_400m_reg <= adc_data_fall;
end else begin
// Output rising edge data
adc_data_400m_reg <= adc_data_rise;
end
adc_data_valid_400m_reg <= 1'b1; // Always valid when ADC is running
end
end
assign adc_data_400m = adc_data_400m_reg;
assign adc_data_valid_400m = adc_data_valid_400m_reg;
endmodule