JP2001127825A - Communication equipment and request resending method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide communication equipment, with which delay or increase in power consumption caused by useless resending is prevented and resetting of request resending waiting time in the case of reconnection based on bus reset can be unnecessitated by performing resending corresponding to the ability of a receiving node. SOLUTION: By measuring time from request transmitting to response (completion) receiving, resending is performed corresponding to the throughput of the receiving node.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a communication apparatus and a request retransmission method for the communication apparatus, and more particularly, to IEEE 1394.
The present invention relates to a communication device that performs communication conforming to a standard and a request retransmission method of the communication device.

[0002]

2. Description of the Related Art Conventionally, IEEE (Institute)
e of Electrical and Select
oronics Engineers) 1394Hig
2. Description of the Related Art A communication device that performs communication in a format conforming to the h Performance Serial Bus standard (hereinafter, referred to as "IEEE 1394 standard") is known. Here, an example of a conventional communication device conforming to the IEEE1394 standard will be described with reference to the drawings.

FIG. 5 is a block diagram showing a configuration of a conventional communication device.

In FIG. 5, a communication device 16 includes a PHY chip 11, a LINK core 12, a FIFO 13,
It is configured to include a PU 14 and a memory 15 such as a RAM.

Referring to FIG. 5, in the conventional communication device 16, data (request) transmitted from the CPU 14
The information is transmitted to another communication device, that is, a receiving node that is a communication partner, via the FO 13, the LINK core 12, and the PHY chip 11.

The data transmitted from the receiving node to the communication device 16 is transmitted to the PHY chip 11 and the LIN
The CPU 14 is notified via the K core 12 and the FIFO 13.

Next, the overall operation of the conventional communication device will be described with reference to FIG. 5 and a flowchart shown in FIG.

FIG. 6 is a flowchart showing the operation of the conventional communication apparatus shown in FIG.

First, the communication device 16, that is, the transmitting node transmits a request to the receiving node (step (C)
-1)). Next, data corresponding to the request transmitted in step (C-1) is received (step (C-2)).

If the received data is a response to the request (steps (C-3) and (C-4)), the process ends.

If the result of step (C-3) indicates that the receiving node is busy, the number of retransmissions performed so far for the request is checked (step (C-5)). If it does not exceed the set number of retransmissions, execute retransmission.

If the result of step (C-5) exceeds the set number of retransmissions, the request is interrupted and error processing is performed.

Next, a protocol model of the IEEE 1394 standard will be described.

FIG. 7 is a diagram showing a sequence chart of the operation of the conventional communication device.

Referring to FIG. 7, a service request issued by a transmitting node and a response (recognition code: ack_complete) for reporting completion of processing corresponding to the service request (hereinafter, referred to as “ack_complete”)
The process up to “response (completed)” is one transaction.

Here, a case where the transmitting node issues a request will be described. If the response of the receiving node can be performed at a sufficiently high speed, a response is executed only once in one transaction as shown in FIG.

FIG. 8 is a diagram showing a sequence chart of the operation of the conventional communication device, and is a diagram showing another example different from FIG.

Referring to FIG. 8, when the response of the receiving node is slow, a response (recognition code: ack_pending) (hereinafter, referred to as “response (pending)”) is assigned between the request and the response. Split the transaction. Other transactions may be performed between the response (pending) and the response (completion).

FIG. 9 is a diagram showing a sequence chart of the operation of the conventional communication device, and is a diagram showing another example different from FIGS.

Further, referring to FIG. 9, when the bus is congested, the receiving node becomes busy. The receiving node uses the acknowledgment code: ack_busy to inform the transmitting node that it is busy and that the request should be retransmitted later.

The transmitting node retransmits at its own timing, and performs retransmission until the response is returned from the receiving node unless the number of retransmissions is exceeded.

Incidentally, Japanese Patent Application Laid-Open No. 11-17775 discloses an interface circuit in a conventional communication device for performing communication conforming to the IEEE 1394 standard.

In the interface circuit disclosed in Japanese Patent Application Laid-Open No. 11-17775, when ack_busy is received, a time (request retransmission waiting time) from when a set retransmission request is received to when retransmission is performed elapses. Retransmission is performed, and when the number of retransmissions reaches a preset number, the transmission operation is stopped.

In the prior art disclosed in Japanese Patent Application Laid-Open No. 11-17775, the values for limiting the request retransmission waiting time and the number of retransmissions can be automatically set, and a smooth transmission / reception process according to the specifications is performed. be able to.

[0025]

However, the above-mentioned prior art has the following problems.

That is, in the prior art, retransmission is performed at the timing of the transmitting node. Therefore, retransmission is performed even when the receiving node is busy, and requests are accumulated in the receiving node. However, there is a problem that the processing load increases. Further, in such a situation, there is a problem that the response of the receiving node is delayed when retransmission is performed.

Further, conventionally, even when the receiving node is busy, useless retransmission is repeated unless the number of retransmissions is exceeded until a response is returned from the receiving node. There was a problem that would.

Incidentally, the above-mentioned Japanese Patent Application Laid-Open No. 11-17775
In the related art disclosed in Japanese Patent Application Laid-Open No. H11-157, the retransmission timing is arbitrarily set, and the retransmission is automatically executed. However, in this conventional technique, when a reconnection is performed, such as a bus reset, the time from receiving a retransmission request each time to performing retransmission (request retransmission waiting time) must be measured and reset. There was a problem.

The present invention has been made in view of the above points. By performing retransmission according to the capability of a receiving node, it is possible to prevent processing delay and increase in power consumption due to useless retransmission, and It is an object of the present invention to provide a communication device capable of eliminating the need for resetting a request retransmission waiting time at the time of reconnection by bus reset.

[0030]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and a transmitting node measures a time from a request transmission to a response (completion) reception. The retransmission can be performed in accordance with the processing capacity of.

Incidentally, the IEEE 1394 standard defines the following.

That is, if the receiving node cannot respond to the request at all, the receiving node recognizes the code: a
The ck_busy is used to inform the sending node that it is busy and that the request should be resent later. Then, the transmitting node retransmits at its own timing, until a response (completion) is returned from the receiving node.
Retransmission is performed unless the number of retransmissions is exceeded.

Therefore, in the present invention, in response to the request issued by the transmitting node, the receiving node recognizes the code: ack_c.
The time until the complete is received is considered to be the data processing capability of the receiving node, and processing is performed using this. That is, when the request is issued, the timer 7 (see FIG.
) Starts timing and the recognition code: ack_com
By stopping the time counting by the timer 7 when receiving the “plette”, the request ~ ack_complete
Time until reception can be measured. The request retransmission waiting time is obtained using the result.

Accordingly, a request retransmission waiting time suitable for the processing capability of the receiving node can be set, retransmission can be performed using the request retransmission waiting time, and retransmission can be performed at the optimum timing for the receiving node. .

Also, in the present invention, the above-described request retransmission waiting time and the EUI 64 of the receiving node are acquired, and the two are associated with each other and stored in a memory as shown in FIG. Even after reconnection, retransmission can be continuously performed based on the request transmission waiting time that matches the data processing capability of the receiving node.

For this reason, for the receiving node that has once measured the request transmission waiting time, after reconnection such as a bus reset is performed, the request transmission waiting time can be measured again without measuring the request transmission waiting time. Time can be set and retransmission can be performed.

Here, the EUI 64 is a node_v stored in a configuration ROM (representing the function of each node) in the SBP-2 standard.
This is a 64-bit unique device number in the world including end_ID and chip_ID.

[0038]

Embodiments of the present invention will be described below with reference to the drawings.

First, the outline of the present invention will be briefly described.

The present invention is based on IEEE (Institute)
of Electrical and Electo
ronics Engineers) 1394 High
In communication performed in a format conforming to the Performance Serial Bus standard (IEEE 1394 standard), when the transmitting node resends a request when the bus is congested, according to the data processing capability of the receiving node (the discrimination of the receiving node is determined by It provides a configuration that allows retransmission to be performed (using EUI 64).

In FIG. 1, data (request) transmitted from the CPU 4 is transmitted to the receiving node via the FIFO 3, the LINK core 2, and the PHY chip 1. The data transmitted from the receiving node is transmitted between the PHY chip 1 and the LINK.
The data is passed to the data analysis unit 6 via the core 2 and the FIFO 3 and analyzed.

As a result of the analysis, if the received data is a response to the request, the transmitting node confirms that the request has been completed. Using the timer 7, the transmitting node measures the time from when the request is transmitted to when the response is received, and measures the processing capability of the receiving node. A request retransmission waiting time is obtained from the measurement result of the processing capacity, and stored in the memory 5.

The request retransmission waiting time is obtained, and
If the received data indicates a busy state of the receiving node as a result of analysis by the data analyzing unit 6 after storing the data in the transmitting node, the transmitting node waits for retransmission for the request retransmission waiting time stored in the memory 5. It is assumed that the busy state of the receiving node is released, and retransmission is performed.

According to the present invention, since the requests are prevented from being accumulated in the receiving node, the processing load on the receiving node can be reduced and the response processing to the request can be performed smoothly. Further, unnecessary retransmission of the transmitting node can be prevented, so that power consumption can be reduced.

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a communication device according to the present invention.

Referring to FIG. 1, a communication device 8 according to the present embodiment includes a PHY chip 1, a LINK core 2, a
It comprises an O3, a CPU 4, a memory 5, a data analyzer 6 for analyzing data, and a timer 7 for measuring time. The communication device 8 is connected to a 1394 bus 9 which is an IEEE 1394 standard bus.
The receiving node 10 is connected to the bus 9.

The data analyzer 6 analyzes the data received from the receiving node 10. The timer 7 starts time measurement at the time when the request is transmitted by the CPU 4, and stops receiving the data when the data analyzed by the data analysis unit 6 is response data to the data. In this way, the time from the request to the response is measured, and the measurement result is stored in the memory 5.

Next, the operation of the embodiment shown in FIG. 1 will be described in detail with reference to the drawings.

FIG. 2 is a flowchart showing the operation of the embodiment shown in FIG.

First, the transmitting node transmits a request (step (A-1)). Next, data corresponding to the request transmitted in step (A-1) is received (step (A-
2)).

Further, the received data is analyzed (step (A-3)), and if it is a response to the request (step (A-4)), the time between the request and the response is measured (step (A-3)). A-5)).

Then, the EUI 64 of the receiving node is determined (step (A-6)), and the optimum request retransmission waiting time is obtained using the measurement result of step (A-5) (step (A-7)). Step (A-6) and Step (A
The values obtained in -7) are stored in the memory 5 in association with each other as shown in FIG. 3 (step (A-8)).

If the result of step (A-3) indicates that the receiving node is busy, the number of retransmissions performed so far for the request is checked (step (A-
9)). If it does not exceed the set number of retransmissions, the EUI 64 of the receiving node is determined, and the request retransmission waiting time of the receiving node is acquired from the memory 5. After the acquired request retransmission waiting time, the transmitting node executes retransmission (step (A-10)). If the result of step (A-9) exceeds the set number of retransmissions, the request is interrupted and error processing is performed.

Next, another embodiment of the present invention will be described.
This will be described in detail with reference to the drawings.

In this embodiment, the configuration of the communication device is the same as that of FIG. 1, and therefore, will be described with reference to the block diagram of FIG.

Referring to FIG. 1, a communication device 8 of the present embodiment includes a PHY chip 1, a LINK core 2, a
It comprises an O3, a CPU 4, a memory 5, a data analyzer 6 for analyzing data, and a timer 7 for measuring time. The communication device 8 is connected to a 1394 bus 9 which is an IEEE 1394 standard bus.
The receiving node 10 is connected to the bus 9.

The data analyzer 6 analyzes data received from the receiving node 10. The timer 7 starts time measurement at the time when the request is transmitted by the CPU 4, and stops receiving the data when the data analyzed by the data analysis unit 6 is response data to the data. In this way, the time from the request to the response is measured, and the measurement result is stored in the memory 5.

Next, the operation of the present embodiment will be described in detail with reference to the drawings.

FIG. 4 is a diagram showing a flowchart of the operation of the present embodiment.

First, the transmitting node transmits a request (step (B-1)). Next, data corresponding to the request transmitted in step (B-1) is received (step (B-
2)).

Further, the received data is analyzed (step (B-3)), and if it indicates the busy state of the receiving node, a busy state code for determining that a busy state code has been returned in response to the request. Check the reception flag (step (B-10)). The number of retransmissions performed so far for the request is checked (step (B-11)).
If it does not exceed the set number of retransmissions, the EUI 64 of the receiving node is determined, and the request retransmission waiting time of the receiving node is acquired from the memory 5. After the acquired request retransmission waiting time, the transmitting node executes retransmission (step (B-12)). If the result of step (B-11) exceeds the set number of retransmissions, the request is interrupted and error processing is performed.

If the result of step (B-3) is a response to the request (step (B-4)), the busy status code reception flag is checked (step (B-5)), and the flag is checked. If is checked, the time until the request and the response is measured (step (B-6)).

Then, the EUI 64 of the receiving node is determined (step (B-7)), and the optimum request retransmission waiting time is calculated using the measurement result of the step (B-5) (step (B-8)). . The values obtained in step (B-6) and step (B-7) are stored in the memory 5 in association with each other as shown in FIG. 3 (step (B-9)). Step (B
If the busy status code reception flag is not checked in -5), the process is terminated. According to this embodiment, effects similar to those of the above-described embodiment can be obtained.
Further, in this embodiment, the request retransmission waiting time is obtained by using only the result of the time measurement between the request and the response performed when the IEEE 1394 bus 9 is congested and the receiving node is busy. Since the request retransmission waiting time measures the timing of retransmission when the receiving node is busy, the time measurement result between request and response when the receiving node can respond sufficiently fast is omitted from the data, An optimum request retransmission waiting time can be obtained as compared with the embodiment described above.

As described above, according to the present invention,
Retransmission (request) after the busy state of the receiving node is released and the receiving node is ready for high-speed data processing
Therefore, the response process can be smoothly performed without accumulating the request in the receiving node, so that the processing load on the receiving node can be reduced, and the response of the receiving node is delayed due to retransmission from the transmitting node. Can be prevented. Further, according to the present invention, by providing a request retransmission waiting time when a transmitting node retransmits, the transmitting node does not repeat unnecessary retransmissions, so that power consumption can be reduced. Further, according to the present invention, the request retransmission waiting time and the EUI 64 for identifying the receiving node are stored in the memory in association with each other, so that the request retransmission waiting time can be measured even when reconnection is performed such as a bus reset. This eliminates the need for rework.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a flowchart of an operation of the embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between data stored in a memory illustrated in FIG. 1;

FIG. 4 is a diagram showing a flowchart of an operation of another embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional example.

FIG. 6 is a diagram showing a flowchart of an operation of a conventional example.

FIG. 7 is a diagram showing a sequence chart of the operation of the conventional example.

FIG. 8 is a diagram showing a sequence chart of the operation of the conventional example.

FIG. 9 is a diagram showing a sequence chart of the operation of the conventional example.

[Explanation of symbols]

 1,11 PHY chip 2,12 LINK core 3,13 FIFO 4,14 CPU 5,15 memory 6 data analysis unit 7 timer 8,16 communication device 9 1394 bus 10 receiving node

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B083 AA01 BB03 CD06 CE01 GG04 5K032 AA02 CC04 DA01 5K034 AA02 AA15 DD02 FF12 HH65 MM03 QQ06

Claims (8)

[Claims] 1. A communication device for performing communication conforming to the IEEE 1394 standard, comprising: a transmitting unit for transmitting a request to a receiving node of a communication partner; transmitting a request by the transmitting unit; and receiving a response from the receiving node. A communication device comprising: a receiving unit; and a retransmission timing determining unit that determines a retransmission timing at which the request is retransmitted by the transmitting unit based on a response received by the receiving unit. 2. The retransmission timing determination means has a timer, and the timer measures a time from when the transmission unit transmits the request until when the reception unit receives a response (completion) by the timer, The communication device according to claim 1, wherein the retransmission timing is determined based on the measured time. 3. The retransmission timing determination means has identification code acquisition means for acquiring an identification code for identifying the receiving node, and determines the retransmission timing for each identification code acquired by the identification code acquisition means. The communication device according to claim 1 or 2, wherein: 4. The communication apparatus according to claim 3, wherein said retransmission timing determination means has storage means for storing the identification code and the retransmission timing in association with each other for each of the identification codes. 5. A request retransmission method for a communication device performing communication conforming to the IEEE 1394 standard, comprising: transmitting a request to a receiving node of a communication partner; transmitting the request; receiving a response from the receiving node; A request retransmission method, wherein retransmission timing for retransmitting the request is determined based on a received response. 6. The method according to claim 1, further comprising measuring a time from when the request is transmitted to when a response (completion) is received from the receiving node, and determining the retransmission timing based on the measured time. The request retransmission method according to claim 5. 7. The request retransmission method according to claim 1, wherein an identification code for identifying the receiving node is obtained, and the retransmission timing is determined for each identification code. 8. The request retransmission method according to claim 7, wherein the identification code and the retransmission timing are stored in association with each other for each of the identification codes.