1 files changed, 41 insertions, 0 deletions
diff --git a/fpga/usrp2/fifo/fifo_2clock_cascade.v b/fpga/usrp2/fifo/fifo_2clock_cascade.v
new file mode 100644
index 000000000..4e8c244c2
--- /dev/null
+++ b/fpga/usrp2/fifo/fifo_2clock_cascade.v
@@ -0,0 +1,41 @@
+
+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, 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;
+   wire 	    src_rdy_int1, src_rdy_int2, dst_rdy_int1, dst_rdy_int2;
+   wire [SIZE-1:0]  level_wclk, level_rclk;
+   wire [4:0] 	    s1_space, s1_occupied, s2_space, s2_occupied;
+   wire [15:0] 	    l_space, l_occupied;
+   
+   fifo_short #(.WIDTH(WIDTH)) shortfifo
+     (.clk(wclk), .reset(arst), .clear(0),
+      .datain(datain), .src_rdy_i(src_rdy_i), .dst_rdy_o(dst_rdy_o),
+      .dataout(data_int1), .src_rdy_o(src_rdy_int1), .dst_rdy_i(dst_rdy_int1),
+      .space(s1_space), .occupied(s1_occupied) );
+   
+   fifo_2clock #(.WIDTH(WIDTH),.SIZE(SIZE)) fifo_2clock
+     (.wclk(wclk), .datain(data_int1), .src_rdy_i(src_rdy_int1), .dst_rdy_o(dst_rdy_int1), .space(l_space),
+      .rclk(rclk), .dataout(data_int2), .src_rdy_o(src_rdy_int2), .dst_rdy_i(dst_rdy_int2), .occupied(l_occupied),
+      .arst(arst) );
+   
+   fifo_short #(.WIDTH(WIDTH)) shortfifo2
+     (.clk(rclk), .reset(arst), .clear(0),
+      .datain(data_int2), .src_rdy_i(src_rdy_int2), .dst_rdy_o(dst_rdy_int2),
+      .dataout(dataout), .src_rdy_o(src_rdy_o), .dst_rdy_i(dst_rdy_i),
+      .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;
+
+   // 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