aboutsummaryrefslogtreecommitdiffstats
path: root/fpga/usrp2/timing/time_64bit.v
diff options
context:
space:
mode:
Diffstat (limited to 'fpga/usrp2/timing/time_64bit.v')
-rw-r--r--fpga/usrp2/timing/time_64bit.v95
1 files changed, 95 insertions, 0 deletions
diff --git a/fpga/usrp2/timing/time_64bit.v b/fpga/usrp2/timing/time_64bit.v
new file mode 100644
index 000000000..51c006962
--- /dev/null
+++ b/fpga/usrp2/timing/time_64bit.v
@@ -0,0 +1,95 @@
+
+
+module time_64bit
+ #(parameter TICKS_PER_SEC = 32'd100000000,
+ parameter BASE = 0)
+ (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 pps_int
+ );
+
+ localparam NEXT_SECS = 0;
+ localparam NEXT_TICKS = 1;
+ localparam PPS_POLSRC = 2;
+ localparam PPS_IMM = 3;
+ localparam TPS = 4;
+
+ reg [31:0] seconds, ticks;
+ wire end_of_second;
+ assign vita_time = {seconds,ticks};
+
+ wire [31:0] next_ticks_preset, next_seconds_preset;
+ wire [31:0] ticks_per_sec_reg;
+ wire set_on_pps_trig;
+ reg set_on_next_pps;
+ wire pps_polarity, pps_source, set_imm;
+
+ setting_reg #(.my_addr(BASE+NEXT_TICKS)) sr_next_ticks
+ (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+ .in(set_data),.out(next_ticks_preset),.changed());
+
+ 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_POLSRC), .width(2)) sr_pps_polsrc
+ (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+ .in(set_data),.out({pps_source,pps_polarity}),.changed());
+
+ setting_reg #(.my_addr(BASE+PPS_IMM), .width(1)) sr_pps_imm
+ (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+ .in(set_data),.out(set_imm),.changed());
+
+ setting_reg #(.my_addr(BASE+TPS), .at_reset(TICKS_PER_SEC)) sr_tps
+ (.clk(clk),.rst(rst),.strobe(set_stb),.addr(set_addr),
+ .in(set_data),.out(ticks_per_sec_reg),.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(set_imm | pps_edge)
+ set_on_next_pps <= 0;
+
+ wire [31:0] ticks_plus_one = ticks + 1;
+
+ always @(posedge clk)
+ if(rst)
+ begin
+ seconds <= 32'd0;
+ ticks <= 32'd0;
+ end
+ else if((set_imm | pps_edge) & set_on_next_pps)
+ begin
+ seconds <= next_seconds_preset;
+ ticks <= next_ticks_preset;
+ end
+ else if(ticks_plus_one == ticks_per_sec_reg)
+ begin
+ seconds <= seconds + 1;
+ ticks <= 0;
+ end
+ else
+ ticks <= ticks_plus_one;
+
+ assign pps_int = pps_edge;
+
+endmodule // time_64bit