Xilinx RocketIO - Page 58

58 www.xilinx.com RocketIO™ Transceiver User Guide
UG024 (v3.0) February 22, 2007
Chapter 2: Digital Design Considerations
R
Additional reset and power control descriptions are given in Table 2-8 and Table 2-9.
VHDL Template
-- Module: gt_reset
-- Description: VHDL submodule
-- reset for GT
--
-- Device: Virtex-II Pro Family
---------------------------------------------------------------------
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;
--
-- pragma translate_off
library UNISIM;
use UNISIM.VCOMPONENTS.ALL;
-- pragma translate_on
--
entity gt_reset is
port (
USRCLK2_M : in std_logic;
LOCK : in std_logic;
REFCLK : out std_logic;
DCM_LOCKED: in std_logic;
RST : out std_logic);
end gt_reset;
--
architecture RTL of gt_reset is
--
signal startup_count : std_logic_vector (7 downto 0);
begin
Table 2-8: Reset and Power Control Descriptions
Ports Description
RXRESET Synchronous receive system reset recenters the receiver elastic buffer, and resets
the 8B/10B decoder, comma detect, channel bonding, clock correction logic,
and other receiver registers. The PLL is unaffected.
TXRESET Synchronous transmit system reset recenters the transmission FIFO, and resets
the 8B/10B encoder and other transmission registers. The PLL is unaffected.
POWERDOWN Shuts down the transceiver (both RX and TX sides).
In POWERDOWN mode, transmit output pins TXP/TXN are not driven, but
biased by the state of transmit termination supply VTTX. If VTTX is not
powered, TXP/TXN float to a high-impedance state. Receive input pins
RXP/RXN respond similarly to the state of receive termination supply VTRX.
Table 2-9: Power Control Descriptions
POWERDOWN Transceiver Status
0 Transceiver in operation
1 Transceiver temporarily powered down
Notes:
1. Unused transceivers are automatically configured as powered-down by the implementation tools.
Product Not Recommended for New Designs