Xilinx RocketIO User Manual page 99

Product Not Recommended for New Designs
Other Important Design Notes
RocketIO™ Transceiver User Guide
UG024 (v3.0) February 22, 2007
-- usrclk2 -- RXUSRCLK2
-- rxreset -- RXRESET
-- rxdata[31:0] RXDATA[31:0] -- (commas aligned to
--
-- rxisk[3:0] - RXCHARISK[3:0]
-- rxrealign -- RXREALIGN
-- rxcommadet -- RXCOMMADET
-- rxchariscomma3 -- RXCHARISCOMMA[3]
-- rxchariscomma1 -- RXCHARISCOMMA[1]
--
LIBRARY IEEE;
USE IEEE.std_logic_1164.all;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.Numeric_STD.all;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY align_comma_32 IS
PORT (
aligned_data
aligned_rxisk
sync
usrclk2
rxreset
rxdata
rxisk
rxrealign
rxcommadet
rxchariscomma3
rxchariscomma1
END ENTITY align_comma_32;
ARCHITECTURE translated OF align_comma_32 IS
SIGNAL rxdata_reg
SIGNAL rxisk_reg
SIGNAL byte_sync
SIGNAL wait_to_sync
SIGNAL count
SIGNAL rxdata_hold
SIGNAL rxisk_hold
SIGNAL sync_hold
BEGIN
aligned_data <= rxdata_hold;
aligned_rxisk <= rxisk_hold;
sync <= sync_hold;
-- This process maintains wait_to_sync and count,
-- which are used only to
-- maintain output sync; this provides some idea
-- of when the output is properly
-- aligned, with the comma in aligned_data[31:24].
-- The counter is set to a high value
-- whenever the elastic buffer is reinitialized;
-- that is, upon asserted RXRESET or
-- RXREALIGN. Count-down is enabled whenever a
-- comma is known to have
-- come through the comma detection circuit, that
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[31:24] or [15:8])
: OUT std_logic_vector(31 DOWNTO 0);
: OUT std_logic_vector(3 DOWNTO 0);
: OUT std_logic;
: IN std_logic;
: IN std_logic;
: IN std_logic_vector(31 DOWNTO 0);
: IN std_logic_vector(3 DOWNTO 0);
: IN std_logic;
: IN std_logic;
: IN std_logic;
: IN std_logic);
: std_logic_vector(15 DOWNTO 0);
: std_logic_vector(1 DOWNTO 0);
: std_logic;
: std_logic_vector(3 DOWNTO 0);
: std_logic;
: std_logic_vector(31 DOWNTO 0);
: std_logic_vector(3 DOWNTO 0);
: std_logic;
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