ep_tx_pcs_8bit: transfer an_tx_en safely between sys->tx domains

On Altera platforms this bug manifests as the minic failing to TX packets correctly and the whole PTP state machine grinding to a halt. This was already fixed in the 16bit version.

ep_tx_pcs_8bit: transfer an_tx_en safely between sys->tx domains
On Altera platforms this bug manifests as the minic failing to TX packets correctly and the whole PTP state machine grinding to a halt. This was already fixed in the 16bit version.
2a4da7db · Wesley W. Terpstra · fa85ad04 · 2a4da7db
Commit 2a4da7db authored Mar 19, 2013 by Wesley W. Terpstra
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Showing with 12 additions and 2 deletions

ep_tx_pcs_8bit.vhd modules/wr_endpoint/ep_tx_pcs_8bit.vhd +12 -2

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--- a/modules/wr_endpoint/ep_tx_pcs_8bit.vhd
+++ b/modules/wr_endpoint/ep_tx_pcs_8bit.vhd
@@ -154,6 +154,7 @@ architecture behavioral of ep_tx_pcs_8bit is
  signal reset_synced_txclk : std_logic;

  signal mdio_mcr_pdown_synced : std_logic;
+  signal an_tx_en_synced       : std_logic;

  signal s_one : std_logic := '1';

@@ -194,6 +195,15 @@ begin
      rst_n_i  => '1',
      data_i   => mdio_mcr_pdown_i,
      synced_o => mdio_mcr_pdown_synced);
+  
+  U_sync_tx_en : gc_sync_ffs
+    generic map (
+      g_sync_edge => "positive")
+    port map (
+      clk_i    => phy_tx_clk_i,
+      rst_n_i  => '1',
+      data_i   => an_tx_en_i,
+      synced_o => an_tx_en_synced);

  phy_tx_data_o <= tx_odata_reg;
  phy_tx_k_o    <= tx_is_k;
@@ -288,7 +298,7 @@ begin
            tx_error           <= '0';

 -- endpoint wants to send Config_Reg
-            if(an_tx_en_i = '1') then
+            if(an_tx_en_synced = '1') then
              tx_state        <= TX_CR1;
              tx_cr_alternate <= '0';
              fifo_rd         <= '0';
@@ -370,7 +380,7 @@ begin
            tx_odata_reg <= an_tx_val_i(15 downto 8);

 -- check if the autonegotiation control still wants the Config_Reg to be sent
-            if(an_tx_en_i = '1') then
+            if(an_tx_en_synced = '1') then
              tx_state <= TX_CR1;
            else
              tx_state <= TX_COMMA;