moved forward from the old branch

2 files changed, 30 insertions, 4 deletions

diff --git a/usrp2/fifo/fifo18_to_fifo36.v b/usrp2/fifo/fifo18_to_fifo36.v
new file mode 100644
index 000000000..25bb215a1
--- /dev/null
+++ b/usrp2/fifo/fifo18_to_fifo36.v
@@ -0,0 +1,20 @@
+
+// For now just assume FIFO18 is same as FIFO19 without occupancy bit
+
+module fifo18_to_fifo36
+  (input clk, input reset, input clear,
+   input [17:0] f18_datain,
+   input f18_src_rdy_i,
+   output f18_dst_rdy_o,
+
+   output [35:0] f36_dataout,
+   output f36_src_rdy_o,
+   input f36_dst_rdy_i
+   );
+
+   fifo19_to_fifo36 fifo19_to_fifo36
+     (.clk(clk), .reset(reset), .clear(clear),
+      .f19_datain({1'b0,f18_datain}), .f19_src_rdy_i(f18_src_rdy_i), .f19_dst_rdy_o(f18_dst_rdy_o),
+      .f36_dataout(f36_dataout), .f36_src_rdy_o(f36_src_rdy_o), .f36_dst_rdy_i(f36_dst_rdy_i) );
+
+endmodule // fifo18_to_fifo36
diff --git a/usrp2/fifo/fifo_2clock_cascade.v b/usrp2/fifo/fifo_2clock_cascade.v
index 5ce726977..4e8c244c2 100644
--- a/usrp2/fifo/fifo_2clock_cascade.v
+++ b/usrp2/fifo/fifo_2clock_cascade.v
@@ -1,8 +1,10 @@
 
 module fifo_2clock_cascade
   #(parameter WIDTH=32, SIZE=9)
-   (input wclk, input [WIDTH-1:0] datain, input src_rdy_i, output dst_rdy_o, output [15:0] space,
-    input rclk, output [WIDTH-1:0] dataout, output src_rdy_o, input dst_rdy_i, output [15:0] occupied,
+   (input wclk, input [WIDTH-1:0] datain, input src_rdy_i, output dst_rdy_o, 
+    output [15:0] space, output [15:0] short_space,
+    input rclk, output [WIDTH-1:0] dataout, output src_rdy_o, input dst_rdy_i, 
+    output [15:0] occupied, output [15:0] short_occupied,
     input arst);
    
    wire [WIDTH-1:0] data_int1, data_int2;
@@ -29,7 +31,11 @@ module fifo_2clock_cascade
       .space(s2_space), .occupied(s2_occupied));
 
    // Be conservative -- Only advertise space from input side of fifo, occupied from output side
-   assign 	    space = {11'b0,s1_space} + l_space;
-   assign 	    occupied = {11'b0,s2_occupied} + l_occupied;
+   assign 	    space 	    = {11'b0,s1_space} + l_space;
+   assign 	    occupied 	    = {11'b0,s2_occupied} + l_occupied;
+
+   // For the fifo_extram, we only want to know the immediately adjacent space
+   assign 	    short_space     = {11'b0,s1_space};
+   assign 	    short_occupied  = {11'b0,s2_occupied};
    
 endmodule // fifo_2clock_cascade