1 files changed, 146 insertions, 0 deletions
diff --git a/fpga/usrp2/timing/time_sync.v b/fpga/usrp2/timing/time_sync.v
new file mode 100644
index 000000000..c0c8e195f
--- /dev/null
+++ b/fpga/usrp2/timing/time_sync.v
@@ -0,0 +1,146 @@
+
+
+module time_sync
+  (input wb_clk_i, input rst_i,
+   input cyc_i, input stb_i, input [2:0] adr_i,
+   input we_i, input [31:0] dat_i, output [31:0] dat_o, output ack_o,
+   input sys_clk_i, output [31:0] master_time_o,
+   input pps_posedge, input pps_negedge, 
+   input exp_pps_in, output exp_pps_out,
+   output reg int_o,
+   output reg epoch_o,
+   output reg pps_o );
+   
+   wire [31:0] master_time_rcvd;
+   reg [31:0]  master_time;
+   reg [31:0]  delta_time;
+
+   reg 	       internal_tick;
+   wire        sync_rcvd, pps_ext;
+   reg [31:0]  tick_time, tick_time_wb;
+   wire        tick_free_run;
+   reg 	       tick_int_enable, tick_source, external_sync;
+   reg [31:0]  tick_interval;
+   reg 	       sync_on_next_pps;
+   reg         sync_every_pps;
+   reg 	       pps_edge;
+   
+   // Generate master time
+   always @(posedge sys_clk_i)
+     if(rst_i)
+       master_time <= 0;
+     else if(external_sync & sync_rcvd)
+       master_time <= master_time_rcvd + delta_time;
+     else if(pps_ext & (sync_on_next_pps|sync_every_pps))
+       master_time <= 0;
+     else
+       master_time <= master_time + 1;
+   assign      master_time_o = master_time;
+   
+   time_sender time_sender
+     (.clk(sys_clk_i),.rst(rst_i),
+      .master_time(master_time),
+      .send_sync(internal_tick),
+      .exp_pps_out(exp_pps_out) );
+
+   time_receiver time_receiver
+     (.clk(sys_clk_i),.rst(rst_i),
+      .master_time(master_time_rcvd),
+      .sync_rcvd(sync_rcvd),
+      .exp_pps_in(exp_pps_in) );
+
+   assign     ack_o = stb_i;
+   wire       wb_write = cyc_i & stb_i & we_i;
+   wire       wb_read = cyc_i & stb_i & ~we_i;
+   wire       wb_acc = cyc_i & stb_i;
+   
+   always @(posedge wb_clk_i)
+     if(rst_i)
+       begin
+	  tick_source <= 0;
+	  tick_int_enable <= 0;
+	  external_sync <= 0;
+	  tick_interval <= 100000-1;  // default to 1K times per second
+	  delta_time <= 0;
+	  pps_edge <= 0;
+	  sync_every_pps <= 0;
+       end
+     else if(wb_write)
+       case(adr_i[2:0])
+	 3'd0 :
+	   begin
+	      tick_source <= dat_i[0];
+	      tick_int_enable <= dat_i[1];
+	      external_sync <= dat_i[2];
+	      pps_edge <= dat_i[3];
+	      sync_every_pps <= dat_i[4];
+	   end
+	 3'd1 :
+	   tick_interval <= dat_i;
+	 3'd2 :
+	   delta_time <= dat_i;
+	 3'd3 :
+	   ;
+	 // Do nothing here, this is to arm the sync_on_next
+       endcase // case(adr_i[2:0])
+
+   always @(posedge sys_clk_i)
+     if(rst_i)
+       sync_on_next_pps <= 0;
+     else if(pps_ext)
+       sync_on_next_pps <= 0;
+     else if(wb_write & (adr_i[2:0] == 3))
+       sync_on_next_pps <= 1;
+   
+   always @(posedge sys_clk_i)
+     if(internal_tick)
+       tick_time <= master_time;
+
+   always @(posedge wb_clk_i)
+     tick_time_wb <= tick_time;
+   
+   assign dat_o = tick_time_wb;
+
+   always @(posedge sys_clk_i)
+     internal_tick <= (tick_source == 0) ? tick_free_run : pps_ext;
+
+   reg [31:0] counter;
+   always @(posedge sys_clk_i)
+     if(rst_i)
+       counter <= 0;
+     else if(tick_free_run)
+       counter <= 0;
+     else
+       counter <= counter + 1;
+   assign     tick_free_run = (counter >= tick_interval);
+   
+   // Properly Latch and edge detect External PPS input
+   reg 	      pps_in_d1, pps_in_d2;
+   always @(posedge sys_clk_i)
+     begin
+	pps_in_d1 <= pps_edge ? pps_posedge : pps_negedge;
+	pps_in_d2 <= pps_in_d1;
+     end
+   assign pps_ext = pps_in_d1 & ~pps_in_d2;
+
+   always @(posedge sys_clk_i)
+     pps_o <= pps_ext;
+   
+   // Need to register this?
+   reg 	  internal_tick_d1;
+   always @(posedge sys_clk_i) internal_tick_d1 <= internal_tick;
+   
+   always @(posedge wb_clk_i)
+     if(rst_i)
+       int_o <= 0;
+     else if(tick_int_enable & (internal_tick | internal_tick_d1))
+       int_o <= 1;
+     else
+       int_o <= 0;
+
+   always @(posedge sys_clk_i)
+     if(rst_i)
+       epoch_o <= 0;
+     else
+       epoch_o <= (master_time_o[27:0] == 0);
+endmodule // time_sync