Merge branch 'uhd_fpga_merge' into pre_merge

1 files changed, 53 insertions, 0 deletions

diff --git a/fpga/usrp2/fifo/fifo19_to_ll8.v b/fpga/usrp2/fifo/fifo19_to_ll8.v
new file mode 100644
index 000000000..4707f7523
--- /dev/null
+++ b/fpga/usrp2/fifo/fifo19_to_ll8.v
@@ -0,0 +1,53 @@
+
+module fifo19_to_ll8
+  (input clk, input reset, input clear,
+   input [18:0] f19_data,
+   input f19_src_rdy_i,
+   output f19_dst_rdy_o,
+
+   output reg [7:0] ll_data,
+   output ll_sof_n,
+   output ll_eof_n,
+   output ll_src_rdy_n,
+   input ll_dst_rdy_n);
+
+   wire  ll_sof, ll_eof, ll_src_rdy;
+   assign ll_sof_n 	= ~ll_sof;
+   assign ll_eof_n 	= ~ll_eof;
+   assign ll_src_rdy_n 	= ~ll_src_rdy;
+   wire ll_dst_rdy 	= ~ll_dst_rdy_n;
+
+   wire   f19_sof 	= f19_data[16];
+   wire   f19_eof 	= f19_data[17];
+   wire   f19_occ 	= f19_data[18];
+   
+   wire advance, end_early;
+   reg state;
+
+   always @(posedge clk)
+     if(reset)
+       state 	  <= 0;
+     else
+       if(advance)
+	 if(ll_eof)
+	   state  <= 0;
+	 else
+	   state  <= state + 1;
+
+   always @*
+     case(state)
+       0 : ll_data = f19_data[15:8];
+       1 : ll_data = f19_data[7:0];
+       default : ll_data = f19_data[15:8];
+       endcase // case (state)
+   
+   assign ll_sof 	 = (state==0) & f19_sof;
+   assign ll_eof 	 = f19_eof & ((f19_occ==1)|(state==1));
+   
+   assign ll_src_rdy 	 = f19_src_rdy_i;
+
+   assign advance 	 = ll_src_rdy & ll_dst_rdy;
+   assign f19_dst_rdy_o  = advance & ((state==1)|ll_eof);
+   
+endmodule // fifo19_to_ll8
+