--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/fpga/sniffer-pps/sync_inputs.v	Tue Aug 29 20:05:23 2023 +0000
@@ -0,0 +1,35 @@
+/*
+ * This Verilog module captures the input synchronizer logic: passing all 3
+ * SIM sniffer inputs through double-DFF synchronizers to bring them into
+ * our internal clock domain.
+ */
+
+module sync_inputs (IntClk, SIM_RST_in, SIM_RST_sync, SIM_CLK_in, SIM_CLK_sync,
+		    SIM_IO_in, SIM_IO_sync);
+
+input IntClk;
+input SIM_RST_in, SIM_CLK_in, SIM_IO_in;
+output SIM_RST_sync, SIM_CLK_sync, SIM_IO_sync;
+reg SIM_RST_sync, SIM_CLK_sync, SIM_IO_sync;
+
+reg SIM_RST_sync1, SIM_CLK_sync1, SIM_IO_sync1;
+
+always @(posedge IntClk)
+	SIM_RST_sync1 <= SIM_RST_in;
+
+always @(posedge IntClk)
+	SIM_RST_sync <= SIM_RST_sync1;
+
+always @(posedge IntClk)
+	SIM_CLK_sync1 <= SIM_CLK_in;
+
+always @(posedge IntClk)
+	SIM_CLK_sync <= SIM_CLK_sync1;
+
+always @(posedge IntClk)
+	SIM_IO_sync1 <= SIM_IO_in;
+
+always @(posedge IntClk)
+	SIM_IO_sync <= SIM_IO_sync1;
+
+endmodule