Merge branch 'master' into mwest/b200_docs

1 files changed, 60 insertions, 0 deletions

diff --git a/fpga/usrp3/lib/xge_interface/xge_handshake.v b/fpga/usrp3/lib/xge_interface/xge_handshake.v
new file mode 100644
index 000000000..251099f57
--- /dev/null
+++ b/fpga/usrp3/lib/xge_interface/xge_handshake.v
@@ -0,0 +1,60 @@
+//
+// Copyright 2013 Ettus Research LLC
+//
+
+//
+//
+// Provide required handshake to Opencores XGE MAC to initiate Rx of one available packet
+// 
+//
+
+
+module xge_handshake
+  (
+   input clk,
+   input reset,
+   output reg pkt_rx_ren,
+   input pkt_rx_avail,
+   input pkt_rx_eop
+   );
+
+   localparam IDLE=0;
+   localparam RX=1;
+
+   reg 	      state;
+   
+
+   always @(posedge clk)
+     if (reset) begin
+	pkt_rx_ren <= 0;
+	state <= IDLE;
+     end else begin
+	case (state)
+	  //
+	  // Wait for pkt_rx_avail to be asserted, then assert pkt_rx_ren next cycle
+	  //
+	  IDLE: begin
+	     if (pkt_rx_avail) begin
+		pkt_rx_ren <= 1;
+		state <= RX;
+	     end else begin
+		pkt_rx_ren <= 0;
+		state <= IDLE;
+	     end
+	  end
+	  //
+	  // Keep pkt_rx_ren asserted until EOF received.
+	  //
+	  RX: begin
+	     if (pkt_rx_eop) begin
+		pkt_rx_ren <= 0;
+		state <= IDLE;
+	     end else begin
+		pkt_rx_ren <= 1;
+		state <= RX;
+	     end
+	  end   
+	     
+	endcase // case(state)
+     end // else: !if(reset)
+endmodule // xge_handshake