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| author | matt | 2009-03-30 22:52:00 +0000 |
|---|---|---|
| committer | matt | 2009-03-30 22:52:00 +0000 |
| commit | c1950e29b0d51926ad036352f8f39ad2ac1a5dbb (patch) | |
| tree | 754540da820f8e5687d00eb9f965ed78c57ba9cc /usrp2/fpga/simple_gemac/flow_ctrl_tx.v | |
| parent | 22b2e334a5fe7a909d936f1c948328418eca0e8c (diff) | |
| download | gnuradio-c1950e29b0d51926ad036352f8f39ad2ac1a5dbb.tar.gz gnuradio-c1950e29b0d51926ad036352f8f39ad2ac1a5dbb.tar.bz2 gnuradio-c1950e29b0d51926ad036352f8f39ad2ac1a5dbb.zip | |
work in progress on a simpler gigabit-only mac
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@10715 221aa14e-8319-0410-a670-987f0aec2ac5
Diffstat (limited to 'usrp2/fpga/simple_gemac/flow_ctrl_tx.v')
| -rw-r--r-- | usrp2/fpga/simple_gemac/flow_ctrl_tx.v | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/usrp2/fpga/simple_gemac/flow_ctrl_tx.v b/usrp2/fpga/simple_gemac/flow_ctrl_tx.v new file mode 100644 index 000000000..9f7556de4 --- /dev/null +++ b/usrp2/fpga/simple_gemac/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
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