Electrical computers and digital data processing systems: input/ – Input/output data processing – Peripheral monitoring
Reexamination Certificate
2000-07-28
2003-09-30
Gaffin, Jeffrey (Department: 2182)
Electrical computers and digital data processing systems: input/
Input/output data processing
Peripheral monitoring
C710S036000, C710S107000, C710S313000, C710S314000
Reexamination Certificate
active
06629159
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital interface, and more particularly, to a method for modifying data of a plug control register in a digital interface.
2. Discussion of the Related Art
FIGS. 1 and 2
show a conventional method for modifying data of a plug control register in a digital interface.
FIG. 1
shows connection state between audio/video nodes in a 1394 serial bus system according to the related art method.
A first audio/video node
20
includes first and second input plug control registers
21
and
22
, and a first input master plug register
23
. The registers
21
,
22
and
23
input and output connection information between audio/video nodes connected to a 1394 serial bus
10
in accordance with a control signal of an application node(not shown). A second audio/video node
30
includes a third input plug control register
31
and a second input master plug register
32
. The registers
31
and
32
input and output connection information between apparatuses connected to the 1394 serial bus
10
in accordance with the control signal of the application node. A third audio/video node
40
includes a fourth input plug control register
41
and a third input master plug register
42
. The registers
41
and
42
input and output connection information connected between the apparatuses connected to the 1394 serial bus
10
in accordance with the control signal of the application node. A fourth audio/video node
50
includes fifth and sixth plug control registers
51
and
52
and a fourth input master plug register
53
. The registers
51
,
52
and
53
input and output connection information between the apparatuses connected to the 1394 serial bus
10
in accordance with the control signal of the application node. A fifth audio/video node
60
includes a plug control register
61
and an output master plug register
62
. The registers
61
and
62
input and output connection information between the apparatuses connected to the 1394 serial bus in accordance with the control signal of the application node.
A related art method for modifying data of a plug control register of audio/video nodes will be described with reference to FIG.
2
.
A channel of transmitting isochronous data from the fifth audio/video node
60
to the first audio/video node
20
by point-to-point connection or broadcast connection is assigned to an application node. The application node writes data of a plug control register and an input plug register within the fifth audio/video node
60
in the plug control register
61
and the second input plug register
22
at the same format.
Afterwards, the application node writes “1” in on-line bit of the plug control register
61
and on-line bit of the second input plug register
22
in the fifth audio/video node
60
to transmit the isochronous data.
Also, the application node records “1” in a broadcast connection counter or a point-to-point connection counter of the plug control register
61
within the fifth audio/video node
60
.
Thus, the isochronous data is transmitted from the fifth audio/video node
60
to the first audio/video node
20
through the channel.
As described above, the isochronous data is transmitted from the fifth audio/video node
60
to the second and fourth audio/video nodes
30
and
40
.
In this situation, the sixth audio/video node transmits a read request signal to the fifth audio/video node
60
to modify data of the plug control register
61
of the fifth audio/video node
60
. Then, the fifth audio/video node
60
inputs a read response signal to the sixth audio/video node and transmits a value of its plug control register
61
to the sixth audio/video node.
The sixth audio/video node records the value of the plug control register
61
of the fifth audio/video node
60
transmitted through the read response signal in a memory as read data. The read data is an argument value.
The sixth audio/video node modifies the argument value and records the modified value in the memory as a data value.
Subsequently, the sixth audio/video node inputs a lock request signal to the fifth audio/video node and transmits the modified data value and the argument value prior to modification.
The fifth audio/video node
60
compares the transmitted argument value with a value of its plug control register
61
. As a result, if the transmitted argument value is equal to the value of the plug control register
61
, the fifth audio/video node
60
modifies the value of the plug control register
61
to the data value.
However, the related art method for modifying data of a plug control register in a digital interface has several problems.
In case where the sixth audio/video node is not entitled to modify the value of the plug control register of the fifth audio/video node
60
after the sixth audio/video node has received a lock transaction, the fifth audio/video node
60
cannot inform the sixth audio/video node which requested the lock transaction that the sixth audio/video node is not entitled to modify the value of the plug control register. Therefore, if the sixth audio/video node receives the lock transaction, the sixth audio/video node determines that the value of the plug control register of the fifth audio/video node has been modified whether lock transaction is entitled to modify the plug control register or not.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a method for modifying data of a plug control register in a digital interface that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a method for modifying data of a plug control register in a digital interface in which it is recognized whether or not a value of a plug control register can be modified using a read/lock transaction between audio/video nodes connected to the digital interface.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a method is provided for updating data of a plug control register in a digital interface having a plurality of audio/video nodes, the method comprising:
if a first audio/video node requests a second audio/video node to update a value of the plug control register through a read/lock transaction, retrieving a signal that determines whether the first audio/video node is entitled to update a value of the plug control register of the second audio/video node;
transmitting the determining signal to the first audio/video node through a lock response packet; and
if the first audio/video node is entitled to update the value of the plug control register of the second audio/video node and if an argument value transmitted from the first audio/video node is equal to the value of the plug control register of the second audio/video node, then updating the value of the plug control register of the second audio/video node with a data value transmitted from the first audio/video node.
According to the above-mentioned features, the present invention has the advantage that, by using a signal that determines whether or not the first audio/video node is entitled to update the value of the plug control register of the second audio/video node when the first audio/video node requests the second audio/video node to update the value of the plug control register through the read/lock transaction, it is possible to update the data of the plug control register only by the audio/video node entitled to update it.
In another aspect, the method for modifying data of a plug control digital interface includes the determining signal being at least one of a signal “resp_complete” indicating that the first audio/video node is entitled to update the value of the plug control register of the second audio/video node and a signal “resp_access_error” indicating that the first audio/video node is not entitled to update the value of the plug control register of the second audio/video node.
In still another aspect, the
Birch & Stewart Kolasch & Birch, LLP
Gaffin Jeffrey
LG Electronics Inc.
Patel Niketa
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