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base: fpga:21a0d0e69aeacf9747bfac0262e0d7ca30a691d9
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fpga:master
fpga:feature/trashernet-soc
fpga:feature/trashernet-as
fpga:fix/gateway
fpga:fix/prot_muxing
fpga:feature/ipv4
fpga:feature/arp
fpga:wip/cococi
fpga:v0.2
fpga:v0.1
..
compare: fpga:da7e329939d12e853acbd7636701350babf5e3f4
Branches Tags
fpga:feature/trashernet-soc
fpga:master
fpga:feature/trashernet-as
fpga:fix/gateway
fpga:fix/prot_muxing
fpga:feature/ipv4
fpga:feature/arp
fpga:wip/cococi
fpga:v0.2
fpga:v0.1

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21a0d0e69a ... da7e329939

1 changed files with 15 additions and 22 deletions
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37
trashernet/trashernet_phy_cdc.vhd
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@ -44,14 +44,14 @@ architecture rtl of trashernet_phy_cdc is
signal phy_phy_in : phy_in_t; signal phy_phy_in : phy_in_t;
-- Helper signals -- Helper signals
signal rx_data_i : byte; signal rx_data_valid_i : std_logic;
begin begin
assert F_CLK_PHY > 2 * F_CLK report "F_CLK_PHY must be at least 2x F_CLK" severity failure;
-- ------------------------------------------------------------------------- -- -------------------------------------------------------------------------
-- Drives: PHY clock domain -- Drives: PHY clock domain
-- ------------------------------------------------------------------------- -- -------------------------------------------------------------------------
-- Reset synchronizer for PHY
rstsync : process(phy_clk, rst) is rstsync : process(phy_clk, rst) is
begin begin
if rst then if rst then
@ -61,7 +61,6 @@ begin
end if; end if;
end process rstsync; end process rstsync;
-- Operate Trashernet in PHY clock domain
trashernet_phy_inst : entity work.trashernet_phy trashernet_phy_inst : entity work.trashernet_phy
generic map( generic map(
F_CLK => F_CLK_PHY F_CLK => F_CLK_PHY
@ -76,22 +75,6 @@ begin
tx_n => tx_n tx_n => tx_n
); );
-- Latch data in PHY clock domain when valid is strobed
-- If the other clock domain is slower than the time it takes for the strobe to synchronize,
-- `phy_phy_out.rx_data` will already have shifted in the next bit and no longer be valid.
-- Therefore, we need to latch it here.
rxdff : process(phy_clk, rst) is
begin
if rst then
rx_data_i <= (others => '0');
elsif rising_edge(phy_clk) then
if phy_phy_out.rx_data_valid then
rx_data_i <= phy_phy_out.rx_data;
end if;
end if;
end process rxdff;
synchronizer_txen_inst : entity work.synchronizer synchronizer_txen_inst : entity work.synchronizer
generic map( generic map(
SIZE => 5 SIZE => 5
@ -115,10 +98,20 @@ begin
a_in => phy_phy_out.rx_data_valid, a_in => phy_phy_out.rx_data_valid,
b_clk => clk, b_clk => clk,
b_rst => rst, b_rst => rst,
b_out => phy_out.rx_data_valid b_out => rx_data_valid_i
); );
phy_out.rx_data <= rx_data_i; -- No need to synchronize in new clock domain as latched data has been stable for a while thanks to the delay in the _valid synchronizer rxdvff : process(clk, rst) is
begin
if rst then
phy_out.rx_data_valid <= '0';
phy_out.rx_data <= (others => '0'); -- Needed for yosys to compile
elsif rising_edge(clk) then
phy_out.rx_data_valid <= rx_data_valid_i;
phy_out.rx_data <= phy_phy_out.rx_data; -- Data should be stable after the time it takes the _valid signal to go through the synchronizer
end if;
end process rxdvff;
cdc_strobe_rxer_inst : entity work.cdc_strobe cdc_strobe_rxer_inst : entity work.cdc_strobe
port map( port map(