1 files changed, 83 insertions, 0 deletions
diff --git a/fpga/usrp2/fifo/fifo19_to_fifo36.v b/fpga/usrp2/fifo/fifo19_to_fifo36.v
new file mode 100644
index 000000000..2f530109f
--- /dev/null
+++ b/fpga/usrp2/fifo/fifo19_to_fifo36.v
@@ -0,0 +1,83 @@
+
+// Parameter LE tells us if we are little-endian.  
+// Little-endian means send lower 16 bits first.
+// Default is big endian (network order), send upper bits first.
+
+module fifo19_to_fifo36
+  #(parameter LE=0)
+   (input clk, input reset, input clear,
+    input [18:0] f19_datain,
+    input f19_src_rdy_i,
+    output f19_dst_rdy_o,
+
+    output [35:0] f36_dataout,
+    output f36_src_rdy_o,
+    input f36_dst_rdy_i,
+    output [31:0] debug
+    );
+
+   reg 		  f36_sof, f36_eof;
+   reg [1:0] 	  f36_occ;
+   
+   reg [1:0] 	  state;
+   reg [15:0] 	  dat0, dat1;
+
+   wire 	  f19_sof  = f19_datain[16];
+   wire 	  f19_eof  = f19_datain[17];
+   wire 	  f19_occ  = f19_datain[18];
+
+   wire 	  xfer_out = f36_src_rdy_o & f36_dst_rdy_i;
+
+   always @(posedge clk)
+     if(f19_src_rdy_i & ((state==0)|xfer_out))
+       f36_sof 	<= f19_sof;
+
+   always @(posedge clk)
+     if(f19_src_rdy_i & ((state != 2)|xfer_out))
+       f36_eof 	<= f19_eof;
+
+   always @(posedge clk)    // FIXME check this
+     if(f19_eof)
+       f36_occ 	<= {state[0],f19_occ};
+     else
+       f36_occ 	<= 0;
+   
+   always @(posedge clk)
+     if(reset)
+       state 	<= 0;
+     else
+       if(f19_src_rdy_i)
+	 case(state)
+	   0 : 
+	     if(f19_eof)
+	       state <= 2;
+	     else
+	       state <= 1;
+	   1 : 
+	     state <= 2;
+	   2 : 
+	     if(xfer_out)
+	       if(~f19_eof)
+		 state 	   <= 1;
+	   // remain in state 2 if we are at eof
+	 endcase // case(state)
+       else
+	 if(xfer_out)
+	   state 	   <= 0;
+
+   always @(posedge clk)
+     if(f19_src_rdy_i & (state==1))
+       dat1 		   <= f19_datain;
+
+   always @(posedge clk)
+     if(f19_src_rdy_i & ((state==0) | xfer_out))
+       dat0 		   <= f19_datain;
+   
+   assign    f19_dst_rdy_o  = xfer_out | (state != 2);
+   assign    f36_dataout    = LE ? {f36_occ,f36_eof,f36_sof,dat1,dat0} :
+			      {f36_occ,f36_eof,f36_sof,dat0,dat1};
+   assign    f36_src_rdy_o  = (state == 2);
+
+   assign    debug = state;
+   
+endmodule // fifo19_to_fifo36