US 2003/0165142 A1 · Method for freezing the states of a receiver during silent line state operation of a network device

Abstract

A method for maintaining the states of a receiver during the silent line state of a network device operating in a low power link suspend mode is presented. Accordingly, a method of freezing the states of the equalizer and keeping the receiver clock locked to a frequency that is approximately equal to that of the input data while providing for rapid adjustment to the phase and thus recovery of the input data is presented. During Silent Line State (SLS), the receiver states are frozen using methods that avoid parasitic decay. Also, the receive clock phase lock loop is locked onto the local transmit clock since the local transmit clock has a frequency approximating the incoming data frequency. During the SLS, the transmitter of the remote network device may have been turned off to conserve power therefore the receiver has no way of immediately knowing the phase of an incoming data. Thus, in order to prevent loss of data, the receiver loops of the receiving network device are trained to the frequency of the transmitting remote network device using periodic Link Suspend packets. Thus, in most cases, only the phase of the incoming signal need be acquired when data arrives. The phase may be quickly acquired using loop bandwidth shift methods whereby the receive clock phase lock loop bandwidth is increased to a value that aids rapid acquisition of the input clock and then, after acquisition, the bandwidth is shifted to a low value to enhance noise rejection during tracking.

Claims44

Dependent claims

An apparatus capable of operating in link suspend mode comprising:

a transmit function for communicating with an external link partner, said transmit function having a clock for timing output data to said external link partner, wherein said external link partner has a receiver and a transmitter;
a receive function capable of receiving input data in a bit stream from said transmitter of said external link partner while operating in link suspend mode, said receive function comprising a clock recovery function and a data recovery function, wherein said clock recovery function recovers clock of said input data from said bit stream by locking onto said bit stream;
and
a communications link coupling said transmitter of said external link partner to said receive function, said receive function detecting when said input data is present in said communications link and locking said clock recovery function onto said bit stream of said input data such that said data recovery function fully recovers said input data.

1 more element

A method for maintaining receiver states during silent line state transitions of a network device operating in link suspend mode comprising:

generating a transmit clock in a transmit function for communicating with an external link partner, said transmit function using said transmit clock to time output data to said external link partner, wherein said external link partner has a receiver and a transmitter;
creating a communications link between said transmitter of said external link partner and a receive function;
and
receiving input data in a bit stream from said transmitter of said external link partner using said receive function, wherein said receive function is capable of receiving said input data while operating in link suspend mode, said receive function comprising a clock recovery function and a data recovery function, said clock recovery function recovering clock of said input data from said bit stream by locking onto said bit stream of said input data when said receive function detects said input data in said communications link such that said data recovery function fully recovers said input data.

1 more element

A method for maintaining the states of a receiver during silent line state transitions of a network device operating in link suspend mode comprising:

generating a transmit clock in a transmit function for communicating with an external link partner, said transmit function using said transmit clock to time output data to said external link partner, wherein said external link partner has a receiver and a transmitter;
creating a communications link between said transmitter of said external link partner and a receive function;
and
using said receive function to receive input data arriving in a bit stream from said transmitter of said external link partner, said receive function receiving said input data while operating in link suspend mode, said receive function having a clock recovery function, an equalizer function having at least one state, and a data recovery function, said receive function freezing said at least one state of said equalizer function and locking said clock recovery function to said transmit clock when said communications link is in silent line state, said receive function detecting when said input data is present in said communications link and unfreezing said at least one state of said equalizer function and conditioning said input data through said equalizer function to compensate for loss to said input data signal due to transmission over said communications link, said receive function locking said clock recovery function to said bit stream of said compensated input data such that said data recovery function fully recovers said input data.

1 more element

Dependencies are inferred from the claim text.

Method for freezing the states of a receiver during silent line state operation of a network device

Life of this patent

Method for freezing the states of a receiver during silent line state operation of a network device

Life of this patent

Abstract

Claims44