US 8,713,232 B2Granted

Apparatus and method for transferring a data signal propagated along a bidirectional communication path within a data processing apparatus

AssigneeThe Regents of the University of Michigan

InventorsSudhir Kumar Satpathy, David Theodore Blaauw, Dennis Michael Sylvester

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Abstract

An apparatus including a first circuit and a second circuit connected in parallel to the bidirectional communication path, and one of the first and second circuits being an active circuit monitoring a value of the data signal on the bidirectional communication path while the other of the first and second circuits being a passive circuit that is not monitoring the value of the data signal. The active circuit initially starts in a low gain state, but on detection of a transition by transition detection circuitry, it enters a high gain state where the switch circuitry disconnects the transition detection circuitry from the bidirectional communication path, and the drive circuitry is activated in order to drive the data signal on the bidirectional communication path to the opposite value. Once the data signal has been driven to the opposite value, the active circuit and the passive circuits switch states.

Claims23

Dependent claims

An apparatus for transferring a data signal propagated along a bidirectional communication path within a data processing apparatus, comprising:

a first circuit and a second circuit connected in parallel to the bidirectional communication path, at any point in time one of the first and second circuits being an active circuit monitoring a value of the data signal on the bidirectional communication path and the other of the first and second circuits being a passive circuit that is not monitoring the value of the data signal;
each of the first circuit and the second circuit comprising:
transition detection circuitry configured, when connected to the bidirectional communication path, to detect a transition in an initial value of the data signal on the bidirectional communication path;
switch circuitry configured to selectively connect the transition detection circuitry to the bidirectional communication path;
drive circuitry configured when active to be responsive to detection of the transition by the transition detection circuitry to drive the data signal on the bidirectional communication path to an opposite value to the initial value;
and
control circuitry configured to control the operation of the transition detection circuitry, switch circuitry and drive circuitry;
the active circuit initially being in a low gain state where the switch circuitry connects the transition detection circuitry to the bidirectional communication path, and the drive circuitry is not active;
the control circuitry of the active circuit being responsive to a signal from the transition detection circuitry indicating that said transition has been detected, to cause the active circuit to enter a high gain state where the switch circuitry disconnects the transition detection circuitry from the bidirectional communication path, and the drive circuitry is activated in order to drive the data signal on the bidirectional communication path to said opposite value;
the control circuitry of the one of the first and second circuits which is currently the active circuit being configured, following the data signal being driven to said opposite value, to place that one of the first and second circuits in a passive state where it then becomes the passive circuit;
and
the control circuitry of the other one of the first and second circuits which is currently the passive circuit being configured, following the data signal being driven to said opposite value, to place that other one of the first and second circuits in said low gain state where it then becomes the active circuit.

9 more elements

A method of operating an apparatus to transfer a data signal propagated along a bidirectional communication path within a data processing apparatus, the apparatus comprising a first circuit and a second circuit connected in parallel to the bidirectional communication path, at any point in time one of the first and second circuits being an active circuit monitoring a value of the data signal on the bidirectional communication path and the other of the first and second circuits being a passive circuit that is not monitoring the value of the data signal, each of the first circuit and the second circuit comprising:

transition detection circuitry for detecting, when connected to the bidirectional communication path, a transition in an initial value of the data signal on the bidirectional communication path;
switch circuitry for selectively connecting the transition detection circuitry to the bidirectional communication path;
drive circuitry which when active is responsive to detection of the transition by the transition detection circuitry to drive the data signal on the bidirectional communication path to an opposite value to the initial value;
and control circuitry for controlling the operation of the transition detection circuitry, switch circuitry and drive circuitry, the method comprising:
initially placing the active circuit in a low gain state where the switch circuitry connects the transition detection circuitry to the bidirectional communication path, and the drive circuitry is not active;
causing the control circuitry of the active circuit, in response to a signal from the transition detection circuitry indicating that said transition has been detected, to place the active circuit in a high gain state where the switch circuitry disconnects the transition detection circuitry from the bidirectional communication path, and the drive circuitry is activated in order to drive the data signal on the bidirectional communication path to said opposite value;
following the data signal being driven to said opposite value, causing the control circuitry of the one of the first and second circuits which is currently the active circuit to place that one of the first and second circuits in a passive state where it then becomes the passive circuit;
and
following the data signal being driven to said opposite value, causing the control circuitry of the other one of the first and second circuits which is currently the passive circuit to place that other one of the first and second circuits in said low gain state where it then becomes the active circuit.

6 more elements

An apparatus for transferring a data signal propagated along a bidirectional communication path within a data processing apparatus, comprising:

first means and second means for connecting in parallel to the bidirectional communication path, at any point in time one of the first and second means being an active means for monitoring a value of the data signal on the bidirectional communication path and the other of the first and second means being a passive means for not monitoring the value of the data signal;
each of the first means and the second means comprising:
transition detection means for detecting, when connected to the bidirectional communication path, a transition in an initial value of the data signal on the bidirectional communication path;
switch means for selectively connecting the transition detection means to the bidirectional communication path;
drive means for driving, when active and in response to detection of the transition by the transition detection means, the data signal on the bidirectional communication path to an opposite value to the initial value;
and
control means for controlling the operation of the transition detection means, switch means and drive means;
the active means initially being in a low gain state where the switch means connects the transition detection means to the bidirectional communication path, and the drive means is not active;
the control means of the active means, responsive to a signal from the transition detection means indicating that said transition has been detected, for causing the active means to enter a high gain state where the switch means disconnects the transition detection means from the bidirectional communication path, and the drive means is activated in order to drive the data signal on the bidirectional communication path to said opposite value;
the control means of the one of the first and second means which is currently the active means, following the data signal being driven to said opposite value, for placing that one of the first and second means in a passive state where it then becomes the passive means;
and
the control means of the other one of the first and second means which is currently the passive means, following the data signal being driven to said opposite value, for placing that other one of the first and second means in said low gain state where it then becomes the active means.

9 more elements

Dependencies are inferred from the claim text.