1 files changed, 43 insertions, 0 deletions
diff --git a/fpga/usrp2/simple_gemac/ll8_to_txmac.v b/fpga/usrp2/simple_gemac/ll8_to_txmac.v
new file mode 100644
index 000000000..3530a0c59
--- /dev/null
+++ b/fpga/usrp2/simple_gemac/ll8_to_txmac.v
@@ -0,0 +1,43 @@
+
+module ll8_to_txmac
+  (input clk, input reset, input clear,
+   input [7:0] ll_data, input ll_sof, input ll_eof, input ll_src_rdy, output ll_dst_rdy,
+   output [7:0] tx_data, output tx_valid, output tx_error, input tx_ack );
+
+   reg [2:0] xfer_state;
+
+   localparam XFER_IDLE      = 0;
+   localparam XFER_ACTIVE    = 1;
+   localparam XFER_WAIT1     = 2;
+   localparam XFER_UNDERRUN  = 3;
+   localparam XFER_DROP      = 4;
+   
+   always @(posedge clk)
+     if(reset | clear)
+       xfer_state 	    <= XFER_IDLE;
+     else
+       case(xfer_state)
+	 XFER_IDLE :
+	   if(tx_ack)
+	     xfer_state <= XFER_ACTIVE;
+	 XFER_ACTIVE :
+	   if(~ll_src_rdy)
+	     xfer_state <= XFER_UNDERRUN;
+	   else if(ll_eof)
+	     xfer_state <= XFER_WAIT1;
+	 XFER_WAIT1 :
+	   xfer_state <= XFER_IDLE;
+	 XFER_UNDERRUN :
+	   xfer_state <= XFER_DROP;
+	 XFER_DROP :
+	   if(ll_eof)
+	     xfer_state <= XFER_IDLE;
+       endcase // case (xfer_state)
+
+   assign ll_dst_rdy 	 = (xfer_state == XFER_ACTIVE) | tx_ack | (xfer_state == XFER_DROP);
+   assign tx_valid 	 = (ll_src_rdy & (xfer_state == XFER_IDLE))|(xfer_state == XFER_ACTIVE);
+   assign tx_data 	 = ll_data;
+   assign tx_error 	 = (xfer_state == XFER_UNDERRUN);
+   
+endmodule // ll8_to_txmac
+