From e0fcbaee124d3e8c4c11bdda662f88e082352058 Mon Sep 17 00:00:00 2001
From: jcorgan
Date: Mon, 8 Sep 2008 01:00:12 +0000
Subject: Merged r9433:9527 from features/gr-usrp2 into trunk.  Adds usrp2 and
 gr-usrp2 top-level components.  Trunk passes distcheck with mb-gcc installed,
 but currently not without them.  The key issue is that when mb-gcc is not
 installed, the build system skips over the usrp2/firmware directory, and the
 firmware include files don't get put into the dist tarball.  But we can't do
 the usual DIST_SUBDIRS method as the firmware is a subpackage.

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@9528 221aa14e-8319-0410-a670-987f0aec2ac5
---
 usrp2/fpga/eth/rtl/verilog/flow_ctrl_tx.v | 36 +++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 usrp2/fpga/eth/rtl/verilog/flow_ctrl_tx.v

(limited to 'usrp2/fpga/eth/rtl/verilog/flow_ctrl_tx.v')

diff --git a/usrp2/fpga/eth/rtl/verilog/flow_ctrl_tx.v b/usrp2/fpga/eth/rtl/verilog/flow_ctrl_tx.v
new file mode 100644
index 000000000..9f7556de4
--- /dev/null
+++ b/usrp2/fpga/eth/rtl/verilog/flow_ctrl_tx.v
@@ -0,0 +1,36 @@
+
+// TX side of flow control -- when other side sends PAUSE, we wait
+
+module flow_ctrl_tx
+  (input        rst,
+   input        tx_clk,
+   //host processor
+   input        tx_pause_en,
+   // From MAC_rx_ctrl
+   input [15:0] pause_quanta,
+   input        pause_quanta_val,
+   // MAC_tx_ctrl
+   output       pause_apply,
+   input        pause_quanta_sub);
+     
+   // ******************************************************************************        
+   // Inhibit our TX from transmitting because they sent us a PAUSE frame
+   // ******************************************************************************
+
+   reg [15:0] 	pause_quanta_counter;
+   reg 		pqval_d1, pqval_d2;		
+
+   always @(posedge tx_clk) pqval_d1 <= pause_quanta_val;
+   always @(posedge tx_clk) pqval_d2 <= pqval_d1;
+
+   always @ (posedge tx_clk or posedge rst)
+     if (rst)
+       pause_quanta_counter <= 0;
+     else if (pqval_d1 & ~pqval_d2)
+       pause_quanta_counter <= pause_quanta; 
+     else if((pause_quanta_counter!=0) & pause_quanta_sub)
+       pause_quanta_counter <= pause_quanta_counter - 1;
+
+   assign	pause_apply = tx_pause_en & (pause_quanta_counter != 0);
+   
+endmodule // flow_ctrl
-- 
cgit