proper time sync to pps

2 files changed, 30 insertions, 5 deletions

diff --git a/timing/time_64bit.v b/timing/time_64bit.v
index ab0c12be6..84f79645c 100644
--- a/timing/time_64bit.v
+++ b/timing/time_64bit.v
@@ -6,11 +6,13 @@ module time_64bit
     (input clk, input rst,
      input set_stb, input [7:0] set_addr, input [31:0] set_data,  
      input pps,
-     output [63:0] vita_time
+     output [63:0] vita_time, output pps_int
      );
 
-   localparam 	   NEXT_TICKS = 1;
    localparam 	   NEXT_SECS = 0;   
+   localparam 	   NEXT_TICKS = 1;
+   localparam      PPS_POL = 2;
+   
    localparam 	   ROLLOVER = TICKS_PER_SEC - 1;	   
    
    reg [31:0] 	   seconds;
@@ -22,6 +24,7 @@ module time_64bit
    wire [31:0] 	   next_seconds_preset;
    wire 	   set_on_pps_trig;
    reg 		   set_on_next_pps;
+   wire 	   pps_polarity;
    
    setting_reg #(.my_addr(BASE+NEXT_TICKS)) sr_next_ticks
      (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
@@ -30,13 +33,33 @@ module time_64bit
    setting_reg #(.my_addr(BASE+NEXT_SECS)) sr_next_secs
      (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
       .in(set_data),.out(next_seconds_preset),.changed(set_on_pps_trig));
+
+   setting_reg #(.my_addr(BASE+PPS_POL)) sr_pps_pol
+     (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+      .in(set_data),.out(pps_polarity),.changed());
+
+   reg [1:0] 	   pps_del;
+   reg 		   pps_reg_p, pps_reg_n, pps_reg;
+   wire 	   pps_edge;
+   
+   always @(posedge clk)  pps_reg_p <= pps;   
+   always @(negedge clk)  pps_reg_n <= pps;
+   always @* pps_reg <= pps_polarity ? pps_reg_p : pps_reg_n;
+   
+   always @(posedge clk)
+     if(rst)
+       pps_del <= 2'b00;
+     else
+       pps_del <= {pps_del[0],pps_reg};
+
+   assign pps_edge = pps_del[0] & ~pps_del[1];
    
    always @(posedge clk)
      if(rst)
        set_on_next_pps <= 0;
      else if(set_on_pps_trig)
        set_on_next_pps <= 1;
-     else if(pps)
+     else if(pps_edge)
        set_on_next_pps <= 0;
    
    always @(posedge clk)
@@ -45,7 +68,7 @@ module time_64bit
 	  seconds <= 32'd0;
 	  ticks <= 32'd0;
        end
-     else if(pps & set_on_next_pps)
+     else if(pps_edge & set_on_next_pps)
        begin
 	  seconds <= next_seconds_preset;
 	  ticks <= next_ticks_preset;
@@ -57,5 +80,7 @@ module time_64bit
        end
      else
        ticks <= ticks + 1;
+
+   assign pps_int = pps_edge;
    
 endmodule // time_64bit
diff --git a/top/u2_core/u2_core.v b/top/u2_core/u2_core.v
index f9ac07a55..2fa490d26 100644
--- a/top/u2_core/u2_core.v
+++ b/top/u2_core/u2_core.v
@@ -678,7 +678,7 @@ module u2_core
 
    time_64bit #(.TICKS_PER_SEC(32'd100000000),.BASE(SR_TIME64)) time_64bit
      (.clk(dsp_clk), .rst(dsp_rst), .set_stb(set_stb), .set_addr(set_addr), .set_data(set_data),
-      .pps(pps_o), .vita_time(vita_time));
+      .pps(pps_o), .vita_time(vita_time), .pps_int());
    
    // /////////////////////////////////////////////////////////////////////////////////////////
    // Debug Pins