Method and apparatus for IEEE 1394 bus analysis

Details Method and apparatus for IEEE 1394 bus analysis Method and apparatus for IEEE 1394 bus analysis

2000-09-14

2003-02-11

Hoff, Marc S. (Department: 2857)

Data processing: measuring, calibrating, or testing

Testing system

Of circuit

C702S117000, C702S122000, C702S186000, C710S043000, C710S052000, C710S105000, C710S015000, C709S200000, C709S212000, C709S220000, C712S220000, C712S223000, C712S200000

Reexamination Certificate

active

06519544

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for IEEE 1394 bus analysis used in product development of a 1394 bus interface circuit.
2. Description of the Related Art
A high speed serial bus conforming to the IEEE 1394 standard (hereinafter referred to as 1394 bus) has been adopted between electronic equipment, for example, between a computer and its peripheral devices, in order to transfer data at a high speed through interconnections each having a small number of electrical lines.
For example, as shown in
FIG. 13
, in order to transfer data between a computer
10
and a digital video camera
11
, 1394 bus interface circuits (nodes)
12
and
13
are connected to the computer
10
and the camera
11
, respectively, and a 1394 cable
14
is connected therebetween. The circuits
12
and
13
are configured in different ways depending on configurations of respective interface circuits provided to the computer
10
and the camera
11
. When developing the 1394 bus interface circuit
13
, there is a need to capture and analyze data on the 1394 cable
14
.
In the prior art, as shown in
FIG. 14
, a 1394 bus analysis interface circuit
15
was disposed between the circuits
12
and
13
, a 1394 cable
14
A was connected between the circuits
13
and
15
, while a 1394 cable
14
B was connected between the circuits
12
and
15
, and a 1394 bus analysis apparatus
16
was connected to the circuit
15
, thereby verifying data on the 1394 bus.
However, since the 1394 bus analysis interface circuit
15
is connected between the interface circuits
12
and
13
, the analysis is carried out events different from that on a bus in an actual system.
Further, although the maximum number of nodes according to the specifications of the IEEE 1394 standard is
63
, there is a system in which the number of nodes is limited to 2, in which case the 1394 bus analysis interface circuit
15
cannot be connected as shown in FIG.
14
.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a method and an apparatus for an IEEE 1394 bus analysis, capable of analyzing an event on a bus between electronic equipment's of a system used actually.
In one aspect of the present invention, there is provided an IEEE 1394 bus analysis method comprising the steps of: preparing an IEEE 1394 bus interface circuit which includes a physical layer circuit connected to an IEEE 1394 bus; and a link layer circuit connected to the physical layer through signal lines in order to transmit to and receive signals from the physical layer, receiving data from the signal lines; storing the received data; and analyzing the stored data.
With this aspect, since a portion receiving signals from the signal lines is not a node of the IEEE 1394 bus, an analysis can be carried out on events on the IEEE bus in the same system as that used actually.
In another aspect of the present invention, there is provided an IEEE 1394 bus analysis interface circuit comprising: a physical layer circuit, connected to an IEEE 1394 bus, having a link power status signal input, the link power status signal input being fixed inactive to function as a repeater; and a data capture circuit, connected to the physical layer circuit through signal lines, capturing data on the signal lines for data analysis.
With this aspect, on a bus reset conforming to the IEEE 1394 standard, a self ID packet including information of link-off (L=‘0’) is outputted from the physical layer circuit onto the 1394 bus, and the physical layer circuit functions as a repeater, thereby an analysis can be carried out on events on the IEEE 1394 bus in the same system as that used actually. Further, a bus analysis can be performed on any system using the IEEE 1394 bus.
Other aspects, objects, and the advantages of the present invention will become apparent from the following detailed description taken in connection with the accompanying drawings.


REFERENCES:
patent: 6202103 (2001-03-01), Vonbank et al.
patent: 6-223046 (1994-08-01), None
Kunzman et al., ‘1394 High Performance Serial Bus: the Digital Interface for ATV’, IEEE, vol. 41, Aug. 1995, pp. 893-894.

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