diff --git a/constraints.py b/constraints.py
index f68e5bb3d..075a955e9 100644
--- a/constraints.py
+++ b/constraints.py
@@ -62,6 +62,8 @@ def get(ns, crg0, norflash0, uart0, ddrphy0):
 TIMESPEC "TSclk50" = PERIOD "GRPclk50" 20 ns HIGH 50%;
 INST "m1crg/wr_bufpll" LOC = "BUFPLL_X0Y2";
 INST "m1crg/rd_bufpll" LOC = "BUFPLL_X0Y3";
+
+PIN "m1crg/bufg_x1.O" CLOCK_DEDICATED_ROUTE = FALSE;
 """
 	
 	return r
diff --git a/verilog/s6ddrphy/s6ddrphy.v b/verilog/s6ddrphy/s6ddrphy.v
index f7cd05faa..daa724ab2 100644
--- a/verilog/s6ddrphy/s6ddrphy.v
+++ b/verilog/s6ddrphy/s6ddrphy.v
@@ -44,16 +44,147 @@ module s6ddrphy #(
 	/* DDR SDRAM pads */
 	output sd_clk_out_p,
 	output sd_clk_out_n,
-	output [NUM_AD-1:0] sd_a,
-	output [NUM_BA-1:0] sd_ba,
-	output sd_cs_n,
-	output sd_cke,
-	output sd_ras_n,
-	output sd_cas_n,
-	output sd_we_n,
+	output reg [NUM_AD-1:0] sd_a,
+	output reg [NUM_BA-1:0] sd_ba,
+	output reg sd_cs_n,
+	output reg sd_cke,
+	output reg sd_ras_n,
+	output reg sd_cas_n,
+	output reg sd_we_n,
 	inout [NUM_D/2-1:0] sd_dq,
 	output [NUM_D/16-1:0] sd_dm,
 	inout [NUM_D/16-1:0] sd_dqs
 );
 
+/* 
+ * SDRAM clock
+ */
+ODDR2 #(
+	.DDR_ALIGNMENT("NONE"),
+	.INIT(1'b0),
+	.SRTYPE("SYNC")
+) sd_clk_forward_p (
+	.Q(sd_clk_out_p),
+	.C0(clk2x_90),
+	.C1(~clk2x_90),
+	.CE(1'b1),
+	.D0(1'b1),
+	.D1(1'b0),
+	.R(1'b0),
+	.S(1'b0)
+);
+ODDR2 #(
+	.DDR_ALIGNMENT("NONE"),
+	.INIT(1'b0),
+	.SRTYPE("SYNC")
+) sd_clk_forward_n (
+	.Q(sd_clk_out_n),
+	.C0(clk2x_90),
+	.C1(~clk2x_90),
+	.CE(1'b1),
+	.D0(1'b0),
+	.D1(1'b1),
+	.R(1'b0),
+	.S(1'b0)
+);
+
+/* 
+ * Command/address
+ */
+
+reg phase_sel;
+always @(negedge clk2x_90)
+	phase_sel <= sys_clk;
+
+reg [NUM_AD-1:0] r_dfi_address_p0;
+reg [NUM_BA-1:0] r_dfi_bank_p0;
+reg r_dfi_cs_n_p0;
+reg r_dfi_cke_p0;
+reg r_dfi_ras_n_p0;
+reg r_dfi_cas_n_p0;
+reg r_dfi_we_n_p0;
+reg [NUM_AD-1:0] r_dfi_address_p1;
+reg [NUM_BA-1:0] r_dfi_bank_p1;
+reg r_dfi_cs_n_p1;
+reg r_dfi_cke_p1;
+reg r_dfi_ras_n_p1;
+reg r_dfi_cas_n_p1;
+reg r_dfi_we_n_p1;
+	
+always @(posedge sys_clk) begin
+	r_dfi_address_p0 <= dfi_address_p0;
+	r_dfi_bank_p0 <= dfi_bank_p0;
+	r_dfi_cs_n_p0 <= dfi_cs_n_p0;
+	r_dfi_cke_p0 <= dfi_cke_p0;
+	r_dfi_ras_n_p0 <= dfi_ras_n_p0;
+	r_dfi_cas_n_p0 <= dfi_cas_n_p0;
+	r_dfi_we_n_p0 <= dfi_we_n_p0;
+	
+	r_dfi_address_p1 <= dfi_address_p1;
+	r_dfi_bank_p1 <= dfi_bank_p1;
+	r_dfi_cs_n_p1 <= dfi_cs_n_p1;
+	r_dfi_cke_p1 <= dfi_cke_p1;
+	r_dfi_ras_n_p1 <= dfi_ras_n_p1;
+	r_dfi_cas_n_p1 <= dfi_cas_n_p1;
+	r_dfi_we_n_p1 <= dfi_we_n_p1;
+end
+
+reg [NUM_AD-1:0] r2_dfi_address_p0;
+reg [NUM_BA-1:0] r2_dfi_bank_p0;
+reg r2_dfi_cs_n_p0;
+reg r2_dfi_cke_p0;
+reg r2_dfi_ras_n_p0;
+reg r2_dfi_cas_n_p0;
+reg r2_dfi_we_n_p0;
+reg [NUM_AD-1:0] r2_dfi_address_p1;
+reg [NUM_BA-1:0] r2_dfi_bank_p1;
+reg r2_dfi_cs_n_p1;
+reg r2_dfi_cke_p1;
+reg r2_dfi_ras_n_p1;
+reg r2_dfi_cas_n_p1;
+reg r2_dfi_we_n_p1;
+	
+always @(negedge clk2x_90) begin
+	r2_dfi_address_p0 <= r_dfi_address_p0;
+	r2_dfi_bank_p0 <= r_dfi_bank_p0;
+	r2_dfi_cs_n_p0 <= r_dfi_cs_n_p0;
+	r2_dfi_cke_p0 <= r_dfi_cke_p0;
+	r2_dfi_ras_n_p0 <= r_dfi_ras_n_p0;
+	r2_dfi_cas_n_p0 <= r_dfi_cas_n_p0;
+	r2_dfi_we_n_p0 <= r_dfi_we_n_p0;
+	
+	r2_dfi_address_p1 <= r_dfi_address_p1;
+	r2_dfi_bank_p1 <= r_dfi_bank_p1;
+	r2_dfi_cs_n_p1 <= r_dfi_cs_n_p1;
+	r2_dfi_cke_p1 <= r_dfi_cke_p1;
+	r2_dfi_ras_n_p1 <= r_dfi_ras_n_p1;
+	r2_dfi_cas_n_p1 <= r_dfi_cas_n_p1;
+	r2_dfi_we_n_p1 <= r_dfi_we_n_p1;
+end
+
+always @(posedge clk2x_90) begin
+	if(phase_sel) begin
+		sd_a <= r2_dfi_address_p1;
+		sd_ba <= r2_dfi_bank_p1;
+		sd_cs_n <= r2_dfi_cs_n_p1;
+		sd_cke <= r2_dfi_cke_p1;
+		sd_ras_n <= r2_dfi_ras_n_p1;
+		sd_cas_n <= r2_dfi_cas_n_p1;
+		sd_we_n <= r2_dfi_we_n_p1;
+	end else begin
+		sd_a <= r2_dfi_address_p0;
+		sd_ba <= r2_dfi_bank_p0;
+		sd_cs_n <= r2_dfi_cs_n_p0;
+		sd_cke <= r2_dfi_cke_p0;
+		sd_ras_n <= r2_dfi_ras_n_p0;
+		sd_cas_n <= r2_dfi_cas_n_p0;
+		sd_we_n <= r2_dfi_we_n_p0;
+	end
+end
+
+// TODO
+assign sd_dq = 32'hzzzzzzzz;
+assign sd_dm = 0;
+assign sd_dqs = 4'hz;
+ 
 endmodule