JPH11177591A - Transmission medium connection device and controller, operating cycle generation device and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the synchronization of operating cycles between a transmission medium and a tansmission medium connecting device by comparing both operating cycles with each other and transmitting a control signal to increase or decrease the counter value of an operating cycle generation device according to the error detected between those two operating cycles through the comparison. SOLUTION: A reference selection means 108 selects the cycle that is inputted from a cycle generation means 107 as a reference cycle and outputs this cycle. An error detection means 109 compares the cycle inputted from the means 108 with the cycle received from a 1st transmission medium 105 and outputs the error that is detected between both cycles. A clock control means 110 accumulates the errors detected by the means 109 and then outputs a clock control signal to increase or decrease the value of a counter 121 of a 1st operating cycle generation device 103 when those accumulated errors exceed a prescribed number. A control signal transmission means 111 transmits the clock control signal to the device 103.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for interconnecting a plurality of transmission media, an apparatus for generating an operation cycle of the transmission medium, and an apparatus for selecting a reference of the operation cycle.

[0002]

2. Description of the Related Art Currently, there is an IEEE1394 interface as a digital interface used in digital AV equipment and computer peripheral equipment. This IE
The EE1394 interface is an interface standardized by IEEE (I Triple E) as a high-speed serial interface for next-generation multimedia (reference literature: High Performance Serial Bus 1394-199).
5: High performance serial bus 1394-199
Five).

In the IEEE 1394 interface, communication is performed in packet units, and there are two types of packets according to the purpose.

One is an isochronous packet used for transmitting real-time data, and the other is an asynchronous packet used for transmitting non-real-time data.
Packet.

In an isochronous packet, a transmission delay time is guaranteed, and it can be transmitted at a constant interval regardless of the use condition of a bus. Therefore, it is used for transmitting digital video data.

On the other hand, the asynchronous packet does not guarantee real-time performance, but has a mechanism for retransmitting the packet when an error or the like occurs.

In the IEEE 1394 interface, all connected devices (hereinafter, referred to as nodes) are 24.57.
It has a 6 MHz clock and operates in synchronization with an 8 KHz cycle (hereinafter referred to as a cycle) created by counting this clock. This cycle is managed by a node called a cycle master. The cycle master also operates as an arbiter for arbitrating bus use rights.

The cycle master itself has 24.57.
It counts 6 MHz clocks and sends a cycle start packet to the bus every 3072 clocks. This cycle start packet is used as a time signal in the entire bus, and all nodes except the cycle master synchronize with the cycle master by resetting their counters when receiving the cycle start packet. . The real-time property is ensured by guaranteeing that the above-mentioned isochronous packet is transmitted once every cycle.

This isochronous packet is transmitted in the cycle immediately after the transmission of the cycle start packet. After the transmission of all isochronous packets is completed, the transmission of asynchronous packets is performed in the remaining time in the cycle. And 125μ
After the elapse of sec, the cycle start packet is transmitted prior to the asynchronous packet, so that the next cycle is started. Before transmitting such an isochronous packet, a time required for transmitting the packet in a cycle is reserved before transmission. Thus, the isochronous packet can be reliably transmitted every cycle.

On the other hand, the IEEE 1394 interface is an interface that operates as a bus. Therefore, the number of devices that can be connected to one bus and the maximum length of a cable are determined due to restrictions on electric propagation. A maximum of 63 devices can be connected to one bus, and the maximum length of a cable that can be used at present is 4.
Limited to 5m.

On the other hand, in the IEEE 1394 interface, it is possible to use a bus bridge for connecting buses and transferring packets mutually. This allows a maximum of 1023 buses to be connected.
The use of such a bridge also enables transmission over a distance of 4.5 m or more.

[0012] Of the packets used in the IEEE 1394 interface, an isochronous packet is identified by a channel number when transmitting. The transmitting device attaches a specific channel number to the packet and transmits the packet to the bus, and the receiving device receives only the isochronous packet having the channel number required to be received. For this reason,
An isochronous packet is not transmitted by specifying a destination. It is also possible for a plurality of nodes to receive one packet.

One asynchronous packet is transmitted by designating a destination. IEEE139
In the four interfaces, all nodes connected to the bus have a virtual 48-bit address space. An asynchronous packet is transmitted as a read or a write to this address space.

FIG. 7 shows the format of a write request packet used for writing. The write request packet 701 is
As information for indicating the destination and the source, a destination 702, a source 703, a write start address 704 which is an address for writing, a write size 705 indicating the size of data to be written, data for writing in a specified address space Is included in the write data 710. In addition, labels 706, rt707, and rt707 are used as information for identifying the type and priority of a packet.
Type 708, pri709, etc. are included.

Further, in the IEEE 1394 interface, the function of the node is controlled using a part of the address space of the node. For example, a register corresponding to the status of the device is defined in the address space, and an instruction to the status of the device is given by writing a value to this register, and the status of the device can be known by reading this register. Therefore, setting an appropriate value for the write start address 704 and the write data 710 of the write request packet 701 in FIG. 7 and transmitting the packet is equivalent to transmitting an instruction or command to the apparatus. .

[0016]

SUMMARY OF THE INVENTION The above-mentioned IEEE 139
As in the case of a 4-interface, when a transmission medium having a cycle (cycle) serving as a reference for operation and operating in synchronization with this cycle to transmit real-time data is connected to each other to transfer packets to each other, The cycle, which is the operation reference, needs to be synchronized between the transmission media performing the transfer. If this synchronization is not established, there is a possibility that packets may be lost.

For example, in the case of IEEE1394, the frequency of the operation clock of each node is 100 ppm at the maximum.
(Parts Per Million) is allowed, that is, an error is generated at a rate of one clock per 10,000 clocks.

Therefore, when considering between two nodes,
At most, an error of one cycle occurs every 0.625 seconds. When a difference occurs between the number of cycles in a certain period, a packet received from one bus cannot be transmitted to the other bus. Further, there is a case where a packet must be transmitted to the other bus even though the packet is not received from one bus.

FIGS. 6A and 6B show an example in which transfer is performed between two transmission media which are not synchronized with each other and which are synchronized with each other in a cycle. The receiving side and the transmitting side in FIGS. 6A and 6B indicate the receiving side and the transmitting side for the transmission medium connection device.

As shown in FIG. 6A, if the period of the transmission medium transmitting the received packet is longer than the period of the transmission medium receiving the packet, the lost packet 601 becomes It becomes impossible to transmit to the transmission medium on the transmission side.

On the other hand, as shown in FIG. 6B, when the cycle of the transmission medium on the transmitting side is shorter than the cycle of the transmission medium on the receiving side of the packet, the generated packet 602 that has not been received is generated.
Must be sent.

Such a lost packet 601 and a generated packet 602 occur once every 0.625 seconds when an error of 100 ppm is considered as described above. Therefore, in order to perform normal packet transfer,
Cycle synchronization is required between the two transmission media on the receiving and transmitting sides.

On the other hand, in order to establish such synchronization, it is possible to easily cope with such a situation that a device for connecting transmission media always serves as a cycle master.
By supplying the cycle generated by a single clock to all the buses by the device connecting the transmission medium, the cycles of all the buses can be synchronized.

However, the cycle master is automatically selected in accordance with a predetermined rule at the stage of initializing the bus, and there is no guarantee that the designated node is selected as the cycle master. Therefore, if the device to which the transmission medium is connected does not become the cycle master, there is a problem that synchronization becomes impossible.

Since the cycle master also operates as an arbiter for the bus, it is desirable that the cycle master be located at the center of the bus connection configuration in view of the time required for the propagation of electricity. On the other hand, when an arbiter exists at a position distant from the center of the bus, there has been a problem that the use efficiency of the bus is reduced.

Furthermore, when synchronizing between transmission media, the necessary synchronization is only the period, but it is also possible to change the frequency of the operation clock which is the basis of each operation period. However, there is a problem that a normal transmission circuit cannot be used to change the operation clock, and the configuration of the device becomes complicated.

[0027]

According to a first aspect of the present invention, there is provided a transmission medium connecting apparatus having an operation cycle determined based on the number of operation clocks.
A transmission medium connection device that connects a plurality of transmission media that operate in synchronization with the operation period generated by the operation period generation device, wherein a period generation unit that generates a reference period, and the operation period of the connected transmission medium. Error detection means for detecting an error by comparing the reference cycle generated by the cycle generation means,
A clock control unit that accumulates the error detected by the error detection unit, and outputs a clock control signal for increasing or decreasing the operation clock when the magnitude of the accumulated error exceeds a predetermined value; And a control signal transmitting means for transmitting the clock control signal to the operation cycle generation device.

A transmission medium connection device according to a second aspect of the present invention has a transmission medium having an operation cycle determined based on the number of operation clocks and operating in synchronization with the operation cycle generated by the operation cycle generation device. A transmission medium connection device that connects a plurality of transmission mediums, selects one reference transmission medium from the connected transmission media, and compares the operation cycle of the reference transmission medium with the operation cycle of the other transmission medium. Error detecting means for detecting an error, and a clock for accumulating the error detected by the error detecting means and increasing or decreasing the operation clock when the magnitude of the accumulated error exceeds a predetermined value. Clock control means for outputting a control signal, and control signal transmission means for transmitting the clock control signal to the operation cycle generation device of a transmission medium other than the reference transmission medium And it features.

The transmission medium connecting apparatus according to the third invention of the present application has an operation cycle determined based on the number of operation clocks, and operates in synchronization with the operation cycle generated by the operation cycle generation apparatus. A transmission medium connection device for connecting a plurality of transmission mediums, wherein a cycle generation means for generating a reference cycle serving as a reference for operation, and the operation cycle or the cycle generation means of a reference transmission medium selected from among the connected transmission media, Error detecting means for selecting any one of the operating cycles of the generated reference cycle, comparing the operating cycle of the connected transmission medium to detect an error, and accumulating the error detected by the error detecting means. A clock control unit that outputs a clock control signal for increasing or decreasing the operation clock when the magnitude of the accumulated error exceeds a predetermined value; Characterized in that it comprises a control signal transmitting means for transmitting the clock control signal to create period generator.

An operation cycle generation device according to a fourth aspect of the present invention has an operation cycle determined based on the number of operation clocks, and a transmission medium that operates in synchronization with the operation cycle generated by the operation cycle generation device. An operation cycle generation device connected, comprising: a counter for counting the operation clock; and an operation cycle output for transmitting a reference signal serving as a reference of the operation cycle to the transmission medium when a value of the counter reaches a predetermined value. Means, a control signal receiving means for receiving and outputting a clock control signal for instructing an increase or decrease of the operation clock, and increasing the value of the counter based on the clock control signal received by the control signal receiving means. Or, a counter control means for decreasing the number is provided.

According to a fifth aspect of the present invention, there is provided an operation cycle generating apparatus having an operation cycle determined based on the number of operation clocks, wherein the transmission medium operates in synchronization with the operation cycle generated by the operation cycle generation apparatus. An operation cycle generation device connected, comprising: a counter for counting the operation clock; and an operation cycle output for transmitting a reference signal serving as a reference of the operation cycle to the transmission medium when a value of the counter reaches a predetermined value. Means, a control period for performing control for increasing or decreasing the operation clock, control signal receiving means for receiving and outputting a clock control signal including the number of clocks to be increased or decreased during the control period, and the clock The control period included in the control signal is measured, and the control period is determined based on the number of clocks to be increased or decreased included in the clock control signal. Counter control equalizing means for outputting a counter control signal for increasing or decreasing the value of the counter by one at regular intervals, and counter control for increasing or decreasing the value of the counter based on the counter control signal Means.

A transmission medium connecting device according to a sixth aspect of the present invention includes a transmission medium having an operation cycle determined based on the number of operation clocks and operating in synchronization with the operation cycle generated by the operation cycle generation device. A transmission medium connection apparatus for connecting a plurality of transmission media, wherein a cycle generation means for generating a reference cycle, and an error for detecting an error by comparing the operation cycle of the connected transmission medium with the reference cycle generated by the cycle generation means. Detecting means for accumulating the errors detected by the error detecting means, and outputting a cycle control signal for extending or shortening the operation cycle when the magnitude of the accumulated errors exceeds a predetermined value. It is characterized by comprising a cycle control means, and a control signal transmission means for transmitting the cycle control signal to the operation cycle generation device.

A transmission medium connection device according to a seventh aspect of the present invention has a transmission medium having an operation cycle determined based on the number of operation clocks and operating in synchronization with the operation cycle generated by the operation cycle generation device. A transmission medium connection device that connects a plurality of transmission mediums, selects one reference transmission medium from the connected transmission media, and compares the operation cycle of the reference transmission medium with the operation cycle of the other transmission medium. Error detecting means for detecting an error, and a cycle for accumulating the errors detected by the error detecting means and extending or shortening the operation cycle when the magnitude of the accumulated error exceeds a predetermined value. It is characterized by comprising a cycle control means for outputting a control signal, and a control signal transmitting means for transmitting the cycle control signal to the operation cycle generation device of a transmission medium other than the reference transmission medium.

The transmission medium connection device according to the eighth aspect of the present invention has a transmission medium having an operation cycle determined based on the number of operation clocks and operating in synchronization with the operation cycle generated by the operation cycle generation device. A transmission medium connection device for connecting a plurality of transmission media, wherein a period generation means for generating a reference period serving as a reference for operation, and an operation period of the reference transmission medium selected from the connected transmission media or the period generation means generates Selecting any one of the operation cycles of the reference cycle to be performed, error detection means for detecting an error by comparing with the operation cycle of the connected transmission medium, and accumulating the error detected by the error detection means, A cycle control unit that outputs a cycle control signal for extending or shortening the operation cycle when the accumulated error exceeds a predetermined value; Characterized in that it comprises a control signal transmitting means for transmitting a periodic control signal.

An operation cycle generation device according to a ninth aspect of the present invention has an operation cycle determined based on the number of operation clocks, and operates on a transmission medium that operates in synchronization with the operation cycle generated by the operation cycle generation device. An operation cycle generation device to be connected, comprising: a counter that counts the operation clock; a control signal reception unit that receives and outputs a cycle control signal that instructs extension or reduction of the operation cycle; and a control signal reception unit. When the value of the counter reaches a predetermined value while the period control signal is not output, a reference signal serving as a reference of the operation period is transmitted to the transmission medium, and the period control signal is received from the control signal receiving unit. When a signal is input, the value of the counter is greater than or equal to a predetermined value by the amount of the clock included in the period control signal, or the reference signal is transmitted to the transmission medium Characterized in that it comprises an operation period output means for transmitting.

The operation cycle generating device according to the tenth aspect of the present invention comprises:
An operation cycle generation device that has an operation cycle determined based on the number of operation clocks and is connected to a transmission medium that operates in synchronization with the operation cycle generated by the operation cycle generation device. Control signal receiving means for receiving and outputting a counting counter, a control period for performing control for extending or shortening the operation period, and a period control signal including the number of times for extending or shortening by one clock within the control period Measuring the control period included in the period control signal, and extending or shortening the operation period by one clock at regular intervals within the control period based on the number of times of extension or shortening included in the period control signal. A period control equalizing unit that outputs a period generation control signal for shortening, and the period generation period control signal is output from the period control equalization unit. When the value of the counter reaches a predetermined value during a period when the reference signal serving as a reference of the operation cycle is transmitted to the transmission medium, and the cycle generation control signal is input from the cycle control equalizing means. An operation cycle output unit that transmits the reference signal to the transmission medium after or before the value of the counter by one clock from a predetermined value based on the cycle generation control signal. I do.

A transmission medium connection control device according to an eleventh aspect of the present invention has an operation cycle determined based on the number of operation clocks, and operates in synchronization with the operation cycle generated by the operation cycle generation device. A transmission medium connection control device that controls a transmission medium connection device that connects a plurality of transmission media, the analysis unit analyzing the connection configuration of the transmission medium, and synchronizing the plurality of transmission media based on an analysis result of the analysis unit. Reference operating means for determining a reference of the operation cycle in the case where the operation is performed, and reference notifying means for notifying the transmission medium connecting device of the reference of the operation cycle determined by the reference determining means, I do.

[0038]

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

(First Embodiment) FIG. 1 is a block diagram showing a main configuration and a connection state of a transmission medium connection device, an operation cycle generation device, and a transmission medium connection control device according to a first embodiment. is there. In the present embodiment, an IEEE 1394 interface is used as a transmission medium.

In this embodiment, the transmission medium connection device 10
1 shows the case where the first transmission medium 105 connects the first transmission medium 105 and the second transmission medium 106 to realize cycle synchronization between the two transmission media.

A transmission medium connection device 101 for connecting two transmission media to transfer packets to each other and for realizing cycle synchronization between the transmission media includes a period generating means 107, a reference selecting means 108, Detecting means 109, clock control means 110, control signal transmitting means 111, and error detecting means 112, clock controlling means 11 connected to the second transmission medium 106.
3. It is composed of control signal transmitting means 114.

Each unit connected to the first transmission medium 105 and each unit connected to the second transmission medium 106 are blocks having equivalent functions, and the number of connected transmission media increases. In such a case, each of the above means is provided by the number thereof.

On the other hand, the transmission medium connection control device 1 which determines the synchronization relationship of the transmission media and controls the transmission medium connection device 101
Reference numeral 02 includes a reference determination unit 115, an analysis unit 116, and a reference notification unit 117.

Further, the first operation cycle generation device 103 connected to the first transmission medium 105, which functions as a cycle master in the first transmission medium 105, and transmits a cycle reference, includes a control signal receiving means 118, Period output means 119, counter control means 120, counter 121
It is composed of Similarly, the second operation cycle generation means 104 connected to the second transmission medium 106 also includes a control signal reception means 122, an operation cycle output means 123, a counter control means 124, and a counter 125.

First, the first operation cycle generation device 103
This clock is measured by the counter 121 with reference to its own clock. Operating cycle output means 119
Monitors the value of the counter 121, generates a cycle timing every 3072 clocks, and transmits it to the first transmission medium 105 as a cycle start packet. Similarly, also in the second transmission medium, the operation cycle output unit 123 transmits a cycle start packet based on the value of the counter 125 of the second operation cycle generation device 104.

As described above, when two transmission media having independent cycles are connected to each other by the transmission medium connection device 101, the analysis of the transmission medium connection control device 102 which detects the connection of the two transmission media is performed. The means 116 collects information about each transmission medium, such as the first transmission medium 105 and the second transmission medium 106, and determines how many transmission media are connected and whether there are any cascade-connected transmission media. Analyze the connection status between transmission media, such as. The detection of the connection and the analysis of the connection state can be performed using an asynchronous packet which is not related to the synchronization of the operation cycle.

The criterion determining means 115 determines only one cycle criterion necessary for all the connected transmission media to operate based on the same cycle criterion based on the analysis result of the analyzing means 116. And the reference notification means 11
7 transmits an instruction indicating the synchronization reference determined by the reference determination means 115 to each transmission medium connection device.

For example, as shown in FIG. 2, seven transmission media of a first transmission medium 204 to a seventh transmission medium 210
Transmission medium connection device 201 to third transmission medium connection device 2
2 are connected in the form shown in FIG. 2 by the three transmission medium connecting devices 03, the analyzing means 116 (not shown in FIG. 2) analyzes the connection status shown in FIG. One transmission medium or one transmission medium connection device is selected from these as a cycle reference.

For example, here, the second transmission medium connection device 2
When 02 is selected as the reference, the reference notification means 117
The second transmission medium connection device 2 is used as a cycle reference for the third transmission medium 206, the fourth transmission medium 207, and the fifth transmission medium 208 with respect to the second transmission medium connection device 202.
A notification indicating that the cycle period of 02 is to be used is issued (the first synchronization realization).

Further, the reference notifying means 117 sends the cycle period of the third transmission medium 206 to the first transmission medium connecting device 201 as a cycle reference of the first transmission medium 204 and the second transmission medium 205. A notification indicating the use is given (second synchronization realization). This is because the operation cycle of the third transmission medium 206 is
Second transmission medium connection device 20 serving as a cycle reference
This is because they are synchronized with the second cycle period.

Further, the reference notifying means 117 uses the cycle period of the fifth transmission medium 208 as a cycle reference of the sixth transmission medium 209 and the seventh transmission medium 210 for the third transmission medium connection device 203. (The second synchronization realization). This is because the operation cycle of the fifth transmission medium 208 is synchronized with the cycle cycle of the second transmission medium connection device 202 serving as the cycle reference by the first synchronization.

When determining the reference of such a cycle, the reference determining means 115 performs the following procedure based on the analysis result of the analyzing means 116 so as to reduce the number of dependent relations to be synchronized by the following procedure. Can be selected. This is possible, for example, by selecting a reference located at the center of the connection configuration of the transmission medium to be synchronized. An increase in the number of dependencies may cause an error or a phase difference, and it is expected that a longer time is required until synchronization is established. Therefore, the number can be reduced. It is desirable to determine the criteria.

For example, in the above example, the second
Although the transmission medium connection device 202 is used as a reference, if the cycle period of the first transmission medium 204 is used as a reference, the third
Transmission medium 206 is synchronized with the cycle period of the first transmission medium 204 (the first synchronization realization), and the fifth transmission medium 2
08 is synchronized with the cycle period of the third transmission medium 206 (second time of synchronization realization), and is further synchronized with the seventh transmission medium 210.
Is synchronized with the cycle period of the fifth transmission medium 208 (the third synchronization realization).

For this reason, the number of times that the process of receiving the cycle and transmitting the signal for controlling the operation cycle is performed twice as compared with the case where the second transmission medium connection device 202 is used as a reference. When the first transmission medium 204 is used as a reference, the number of times is three (the number of times of realizing the synchronization). Therefore,
It is more preferable to select the cycle reference of the second transmission medium connection device 202 than to select the cycle period of the first transmission medium 204.

As described above, based on the analysis result of the connection relationship between the transmission media received from the analyzing means 116, the reference determining means 115 sets the cycle period so that the number of times of performing the control processing for realizing the synchronization becomes small. Select criteria.

On the other hand, in FIG. 1, the transmission medium connection device 101, which has received the notification indicating the reference of the cycle period from the transmission medium connection control device 102, synchronizes the cycle period based on this instruction. Perform the operation of

First, when the instruction received from the transmission medium connection control apparatus 102 is based on the cycle period of the transmission medium connection apparatus 101, the reference selection means 108 sets the cycle generation means 107 as the cycle cycle reference.
Selects and outputs the cycle period input from. The period generating means 107 counts its own clock of 24.576 MHz and outputs 8 KHz every 3072 clocks.
Is generated.

Next, the error detecting means 109 is the reference selecting means 1
08 and the first transmission medium 1
05 and compares the received cycle periods and outputs the error. The clock control means 110 is connected to the error detection means 10
9 accumulates the detected errors, and outputs a clock control signal for increasing or decreasing the value of the counter 121 of the first operation cycle generation device 103 when this error becomes equal to or more than a predetermined value. Such a clock control signal is generated, for example, when an error between the reference cycle period and the cycle period received from the first transmission medium 105 is one or more operation clocks. That is, when the difference between the two periods exceeds about 40.7 nsec corresponding to one clock at 24.576 MHz, which is the operation clock of the IEEE 1394 interface, clock control for increasing or decreasing the value of the counter 121 by one clock. Output a signal.

Since the signal is as described above, if the cycle period generated by the first operation period generation device 103 is shorter than the period generated by the period generation unit 107, the clock control signal , On the other hand, if the cycle period generated by the first operation period generation device 103 is longer than the period generated by the period generation unit 107, It includes an instruction to increase the value.

The control signal transmission means 111 transmits the clock control signal output from the clock control means 110 to the first operation cycle generation device 103 via the first transmission medium 105.

For transmitting the clock control signal, the asynchronous packet shown in FIG. 7 can be used. In this case, a register for increasing or decreasing the value of the counter 121 is defined in the address space of the operation cycle generation device 103, and a clock control signal is transmitted by writing the number of clocks to be increased or decreased to this register. The number of clocks for increasing or decreasing the counter 121 is included in the write data 710 and transmitted.

On the other hand, the control signal receiving means 118 of the first operation cycle generation device 103 which receives this clock control signal
Outputs the clock control signal received from the first transmission medium 105 to the counter control means 120. The counter control unit 120 increases or decreases the value of the counter 121 according to the input clock control signal. As a result, the value of the counter 121 increases or decreases, and the cycle length is extended or shortened by the designated clock.

As described above, the cycle period of the first transmission medium generated by the first operation cycle generation device 103 is
It can be synchronized with the cycle period generated by the period generating means 107 of the transmission medium connection device 101.

Further, for the second transmission medium 106, similarly to the above, the error detection means 112 detects an error, the clock control means 113 outputs a clock control signal, and the control signal transmission means 114 A control signal is transmitted to the second operation cycle generation device 104. On the other hand, this is received by the control signal receiving means 122 of the second operation cycle generation device 104, and the counter control means 124 increases or decreases the value of the counter 125, so that the cycle cycle of the second transmission medium 106 is also reduced. This is synchronized with the cycle period of the cycle generation unit 107 of the transmission medium connection device 101.

On the other hand, the instruction received from the transmission medium connection control device 102 is not based on the cycle period of the transmission medium connection device 101, but the instruction received from the transmission medium connection control device 102 is 10
1 is not based on the internal cycle period, that is, the transmission medium connection device 101 sends the first
When the notification indicating that the cycle period of the transmission medium 105 is used is received, the reference selecting unit 108 of the transmission medium connection device 101 selects and outputs the cycle period received from the first transmission medium 105. . In this case, the first
In the error detecting means 109 connected to the transmission medium 105, no error occurs and no clock control signal is output because the comparison target and the reference have the same cycle period.

On the other hand, the error detecting means connected to the second transmission medium 106 determines the cycle period received from the second transmission medium 106 and the cycle period of the first transmission medium 105 inputted from the reference selecting means 108. The error is detected by comparison. The increase or decrease of the value of the counter based on the detected error is the same as the case where the cycle period generated by the period generating means 107 is used as a reference.

By using only an instruction to increase or decrease the value of the counter 121 by 1 as the clock control signal, the configurations of the clock control means 110 and 113 and the counter control means 120 and 124 are simplified. It is possible to do.

(Second Embodiment) FIG. 3 is a block diagram showing a main configuration and a connection state of a transmission medium connection device, an operation cycle generation device, and a transmission medium connection control device according to a second embodiment. is there. Also in this embodiment, an IEEE 1394 interface is used as a transmission medium. Also, as in the first embodiment, the transmission medium connection device 301 includes the first transmission medium 105 and the second transmission medium 106.
Are connected to realize cycle synchronization between two transmission media.

The means for realizing the same operations as in the first embodiment are denoted by the same reference numerals, and unless otherwise specified, this embodiment will be the same as the first embodiment. It is assumed that the same operation is realized.

A transmission medium connecting device 301 for connecting two transmission media to transfer packets to each other and realizing cycle synchronization between the transmission media includes a period generating means 107, a reference selecting means 108, Detecting means 109, clock control means 304, control signal transmitting means 111, and error detecting means 112, clock controlling means 30 connected to the second transmission medium 106.
5. It is composed of control signal transmitting means 114. Note that each unit connected to the first transmission medium 105 and each unit connected to the second transmission medium 106 are blocks having the same function, and when the number of connected transmission media increases, Is provided with each of the means described above.

On the other hand, the transmission medium connection control 102 which determines the synchronization relationship of the transmission medium and controls the transmission medium connection device 301
Is composed of a reference determination unit 115, an analysis unit 116, and a reference notification unit 117.

Further, the first operation cycle generation device 302 connected to the first transmission medium 105, which functions as a cycle master in the first transmission medium 105, and transmits a cycle reference, includes a control signal receiving means 118, Period output means 119, counter equalization means 306, counter 12
1 Similarly, the second operation cycle generation means 303 connected to the second transmission medium 106 also includes a control signal reception means 122, an operation cycle output means 123, a counter equalization means 307, and a counter 125.

First, the counter 121 and the operation cycle output means 119 of the first operation cycle generation device 302 and the counter 125 and the operation cycle output means 123 of the second operation cycle generation device 303 are different from those of the first embodiment. The same operation is performed, and the first transmission medium 105 and the second transmission medium 1
At step 06, a cycle start packet is transmitted as a cycle period.

The transmission medium connection control device 102 is also the first
In the same manner as in the embodiment, the analyzing means 116 analyzes the connection state of the transmission medium, and based on the result, the reference determining means 115 determines the reference of the cycle period. And the standard notification means 1
17 is for notifying the transmission medium connection device 301 of the reference according to the determined reference.

On the other hand, the reference selecting means 108 of the transmission medium connection device 301 selects and outputs a reference cycle period in accordance with the notification received from the transmission medium connection control device 102. This cycle criterion may be the operation cycle generated by the cycle generation means 107 of the transmission medium connection device 301 or one operation cycle of the connected transmission medium, as in the first embodiment. good. Then, the clock control unit 304 inputs the cycle reference and the cycle error of the first transmission medium 105 output from the error detection unit 109, and calculates the ratio of the cycle period length from the accumulated value of the error and the accumulated period. Ask. The clock control means 304 determines a control period for controlling the clock and the number of clocks to be increased or decreased during the control period based on the obtained ratio.
These two values are output as clock control signals.

For example, if the cycle based on the cycle and the cycle of the first transmission medium 105 have an error of 10 ppm, an error occurs at a rate of one clock per 100,000 clocks. This corresponds to an error of one clock every 32.6 cycles. Therefore, the clock control means 304
Makes this ratio a positive number ratio, 5 times during 163 cycles.
An instruction to increase or decrease the value of the counter 121 by the clock is output as a clock control signal. This clock control signal is transmitted to the first operation cycle generation device 30 by the control signal transmission means 111 as in the first embodiment.
2 is sent.

Also in this case, similarly to the first embodiment,
The clock control signal can be transmitted in the form of an asynchronous packet. FIG. 8 shows an example of a packet for transmitting a clock control signal. The clock control signal packet 801 has a control period 802 and a clock number of 8 as the asynchronous packet write data 710 shown in FIG.
03, which is transmitted to an address of a register defined for controlling the value of the counter 121, as in the first embodiment.

The above operation is the same for the second transmission medium 106. The clock control means 305 uses the control period and the number of clocks to be increased or decreased during this period as a clock control signal as the second operation period generation means. 303.

The control signal receiving means 118 of the first operation cycle generating device 302 outputs the received clock control signal to the counter equalizing means 306. Counter equalizing means 3
06 measures the control period included in the clock control signal and received from the transmission medium connection device 301, and increases or decreases the counter 121 by one clock at regular intervals during this control period. For example, when a clock control signal indicating an increase of 5 clocks is received during 163 cycles as in the above-described example, the counter 121 is incremented by one clock every 32 to 33 cycles.

As described above, the value of the counter 121 is increased or decreased by the clock control signal received from the transmission medium connection device 301, and as a result, the cycle generated by the first operation cycle generation device 302 is extended or shortened. It will be. Thus, the operation cycle of the first transmission medium 105 can be synchronized with the cycle reference selected by the transmission medium connection device 301.

As described above, the present embodiment is different from the first embodiment in that the clock control signal includes two parameters: the control period and the number of clocks to be increased or decreased during the control period. Is different. As described above, by including the control period and the number of clocks to be increased or decreased during the control period in the clock control signal, a uniform cycle can be generated as compared with the first embodiment.

Note that once the counter equalizing means 306 receives the clock control signal, the same processing can be continued until the next clock control signal is received. That is, in the case of the above example, 5 times every 163 cycles.
Increase clock. Thus, when the clock control unit 304 of the transmission medium connection device 301 generates an appropriate clock control signal, it is only necessary to transmit the clock control signal once, and it is not necessary to transmit the clock control signal thereafter.

The above operation is the same for the second transmission medium 106 and the second operation cycle generation device 303. The reference of the cycle period is the case where the cycle generation means 107 of the transmission medium connection device 301 is used.
The above operation can be realized both in the case of using any one of the second transmission medium 106 and the second transmission medium 106.

(Third Embodiment) FIG. 4 is a block diagram showing a main configuration and a connection state of a transmission medium connection device, an operation cycle generation device, and a transmission medium connection control device according to a third embodiment. is there. Also in this embodiment, an IEEE 1394 interface is used as a transmission medium. Further, similarly to the first and second embodiments, the transmission medium connection device 401 connects the first transmission medium 105 and the second transmission medium 106, and realizes cycle synchronization between the two transmission media. The case is shown.

The means for realizing the same operations as those in the first and second embodiments are denoted by the same reference numerals, and unless otherwise specified, the first and second embodiments are also used in this embodiment. It is assumed that the same operation as that of the second embodiment is realized.

A transmission medium connecting device 401 for connecting two transmission media to transfer packets to each other and realizing cycle synchronization between the transmission media includes a period generating means 107, a reference selecting means 108, and a first selecting means 108. Detecting means 109, cycle controlling means 404, control signal transmitting means 111 connected to the first transmission medium 105, and error detecting means 112, cycle controlling means 405, control signal transmitting means 114 connected to the second transmitting medium 106. It is composed of Note that each unit connected to the first transmission medium 105 and the second transmission medium 106
Is a block having the same function, and when the number of connected transmission media increases, each unit is provided with the number of units.

On the other hand, the transmission medium connection control 102 for determining the synchronization relationship of the transmission medium and controlling the transmission medium connection device 401
Is composed of a reference determination unit 115, an analysis unit 116, and a reference notification unit 117.

Further, the first operation cycle generation device 402 connected to the first transmission medium 105, which functions as a cycle master in the first transmission medium 105, and transmits a cycle reference, includes a control signal receiving means 118, It comprises a period output means 406 and a counter 121. Similarly, the second operation cycle generating means 403 connected to the second transmission medium 106 is also constituted by the control signal receiving means 122, the operation cycle output means 407, and the counter 125.

First, the counter 121 and the operation cycle output means 406 of the first operation cycle generation device 402 and the counter 125 and the operation cycle output means 407 of the second operation cycle generation device 403 are different from those of the first embodiment. The same operation is performed, and the first transmission medium 105 and the second transmission medium 1
At step 06, a cycle start packet is transmitted as a cycle period.

The transmission medium connection control device 102 is also the first
In the same manner as in the embodiment, the analyzing means 116 analyzes the connection state of the transmission medium, and based on the result, the reference determining means 115 determines the reference of the cycle period. And the standard notification means 1
17 is for notifying the transmission medium connection device of the reference in accordance with the determined reference.

On the other hand, the reference selecting means 108 of the transmission medium connection device 401 selects and outputs a reference cycle period in accordance with the notification received from the transmission medium connection control device 102. This cycle reference may be the operation cycle generated by the cycle generation means 107 of the transmission medium connection device 401, as in the first and second embodiments, or one operation cycle of the connected transmission medium. It may be. Then, the cycle control unit 404 inputs the cycle reference and the cycle error of the first transmission medium 105 output by the error detection unit 109, and outputs a cycle control signal for extending or shortening the cycle.

The cycle control signal is transmitted, for example, by the cycle generation means 10.
In the case where the cycle period of the cycle No. 7 is used as a reference, and when the cycle of the cycle generated by the first operation cycle generation device 402 is shorter than the cycle generation means 107, an instruction to extend the cycle is included. On the other hand, when the cycle period generated by the first operation period generation device 402 is longer than the period generated by the period generation means 107, the instruction includes an instruction to shorten the cycle.

Note that this extension or shortening instruction is
It can be represented by increasing or decreasing the number of clocks in a cycle. Further, the cycle control signal can be transmitted by an asynchronous packet as in the first and second embodiments.

The control signal receiving means 118 of the first operation cycle generation device 402 which receives the cycle control signal outputs the cycle control signal received from the first transmission medium 105 to the operation cycle output means 406. The operation cycle output means 406
If nothing is input from the control signal receiving means 118, a cycle start packet is sent to the transmission medium 105 every time the value of the counter 121 reaches 3072 as described above.

On the other hand, when the period control signal is input from the control signal receiving means 118, the transmission medium connecting device 401
And generates an extended or shortened cycle according to the cycle control signal received from.

For example, if the cycle control signal indicates the generation of a cycle shortened by one clock, the operation cycle output means 406 resets the counter 121 when the value of the counter 121 reaches 3071, and Send a start packet. Conversely, if the cycle control signal indicates the generation of a cycle extended by one clock,
Clock measurement is continued until the value of the counter 121 reaches 3073. When the value of the counter 121 reaches 3073, the counter 121 is reset and a cycle start packet is transmitted.

As described above, according to the cycle control signal received from the transmission medium connection device 401, the cycle generation means 10
The operation cycle in which 7 occurs is extended or shortened. Thereby, the operation cycle of the first transmission medium 105 becomes
It is possible to synchronize with the cycle reference selected by the transmission medium connection device 401.

The above operation is the same for the second transmission medium 106 and the second operation cycle generation device 403. The reference of the cycle period is the case where the cycle generation means 107 of the transmission medium connection device 401 is used.
The above operation can be realized both in the case of using any one of the second transmission medium 106 and the second transmission medium 106.

As described above, the present embodiment differs from the first embodiment in that the value of the counter for generating a cycle is changed instead of increasing or decreasing the value of the counter of the operation cycle generation device. I have. As described above, since the value for generating the cycle start packet is changed, the means for adding and subtracting to increase or decrease the value of the counter becomes unnecessary, and the configuration of the apparatus can be simplified.

By using only one clock as the number of clocks to be extended or shortened as the cycle control signal, the configurations of the cycle control means 404 and 405 and the operation cycle output means 406 and 407 can be simplified. Becomes

(Fourth Embodiment) FIG. 5 is a block diagram showing a main configuration and a connection state of a transmission medium connection device, an operation cycle generation device, and a transmission medium connection control device according to a fourth embodiment. is there. Also in this embodiment, an IEEE 1394 interface is used as a transmission medium. Further, similarly to the first to third embodiments, the transmission medium connection device 501 connects the first transmission medium 105 and the second transmission medium 106, and realizes cycle synchronization between the two transmission media. The case is shown.

The means for realizing the same operations as those of the first and second embodiments are denoted by the same reference numerals, and unless otherwise specified, the first to second embodiments are also used in this embodiment. Third
It is assumed that the same operation as that of each embodiment is realized.

A transmission medium connecting device 501 for connecting two transmission media to transfer packets to each other and realizing cycle synchronization between the transmission media includes a period generating means 107, a reference selecting means 108, and a first selecting means 108. Detecting means 109, cycle controlling means 504, control signal transmitting means 111 connected to the second transmission medium 106, and error detecting means 112, cycle controlling means 505, control signal transmitting means 114 connected to the second transmitting medium 106. It is composed of Note that each unit connected to the first transmission medium 105 and the second transmission medium 106
Is a block having the same function, and when the number of connected transmission media increases, each unit is provided with the number of units.

On the other hand, the transmission medium connection control 102 which determines the synchronization relationship of the transmission medium and controls the transmission medium connection device 501
Is composed of a reference determination unit 115, an analysis unit 116, and a reference notification unit 117.

Further, the first operation cycle generation device 502 connected to the first transmission medium 105, which functions as a cycle master in the first transmission medium 105, and transmits a cycle reference, includes the control signal receiving means 118, Period output means 406, period control equalization means 506, counter 12
1 Similarly, the second operation cycle generation means 503 connected to the second transmission medium 106 also includes the control signal reception means 122, the operation cycle output means 407, the cycle control equalization means 507, and the counter 125.

First, the counter 121 and the operation cycle output means 406 of the first operation cycle generation device 502 and the counter 125 and the operation cycle output means 407 of the second operation cycle generation device 503 are different from those of the third embodiment. The same operation is performed, and the first transmission medium 105 and the second transmission medium 1
At step 06, a cycle start packet is transmitted as a cycle period.

The transmission medium connection control device 102 is also the first
As in the third to third embodiments, the analyzing means 116 analyzes the connection status of the transmission medium, and based on the result, the reference determining means 115 determines the reference of the cycle period. Then, the reference notifying unit 117 notifies each transmission medium connection device of the reference according to the determined reference.

On the other hand, the reference selecting means 108 of the transmission medium connection device 501 selects and outputs a reference cycle period in accordance with the notification received from the transmission medium connection control device 102. This cycle criterion is the same as that of the first to third embodiments.
07 may occur, or may be one operation cycle of the connected transmission medium. The cycle control unit 504 inputs the cycle reference and the cycle error of the first transmission medium 105 output from the error detection unit 109, and obtains the ratio of the cycle period length from the accumulated error value and the accumulation period. . The cycle control means 504 determines a control period for controlling the cycle and the number of cycles to be extended or shortened during the control period based on the obtained ratio.
Are output as cycle control signals.

For example, in the same example as in the second embodiment, if the cycle reference cycle and the cycle of the first transmission medium 105 have an error of 10 ppm, 5 cycles (163 times) between 163 cycles. Only, it outputs a cycle control signal indicating extension or shortening of one clock.

The control signal transmitting means 111 transmits this cycle control signal to the first operation cycle generation device 502. In this case as well, as in the first to third embodiments, the cycle control signal can be transmitted by the asynchronous packet. In the packet shown in FIG. 8, a packet including the cycle number is used instead of the clock number. Can be.

The above operation is performed by the second transmission medium 106
Similarly, the cycle control unit 505 transmits the control period and the number of cycles to be extended or shortened during this period to the second operation cycle generation unit 503 as a cycle control signal.

The control signal receiving means 118 of the first operation cycle generation device 502 outputs the received manual control signal to the cycle control equalization means 506. Period control equalizing means 506
Is a transmission medium connection device 501 based on a cycle control signal.
And outputs a signal to the operation cycle output means 406 to instruct the operation cycle output means 406 to extend or shorten the cycle by one clock at regular intervals during this control period. For example, when a cycle control signal indicating an extension of 5 cycles is received during 163 cycles as in the above-described example, a signal for instructing to extend the cycle by one clock is output every 32 to 33 cycles. Output to means 406.

As described above, according to the cycle control signal received from the transmission medium connection device 501, the operation cycle generated by the operation cycle generation device 502 is extended or shortened. Can be synchronized with the cycle reference selected by the transmission medium connection device 501.

As described above, the present embodiment differs from the third embodiment in that the period control signal includes two parameters: the control period, and the number of cycles to be extended or shortened by one clock within the control period. Is different. As described above, by including the control period and the number of cycles to be extended or shortened in the control period in the cycle control signal,
A more uniform cycle can be generated as compared with the embodiment.

Note that once the cycle control equalizing means 506 receives the cycle control signal, it can continue the same processing until it receives the next cycle control signal. That is, in the case of the above-described example, a signal indicating extension by 5 cycles every 163 cycles is output to the operation cycle output unit 406. Accordingly, when the cycle control unit 504 of the transmission medium connection device 501 generates an appropriate cycle control signal, it is only necessary to transmit the cycle control signal once, and it is not necessary to subsequently transmit the handwritten control signal.

The above operation is the same for the second transmission medium 106 and the second operation cycle generation device 503. The reference of the cycle period is based on the case where the cycle generation means 107 of the transmission medium connection device 501 is used.
The above operation can be realized both in the case of using any one of the second transmission medium 106 and the second transmission medium 106.

The reference selecting means 108 and the error detecting means 109 of the transmission medium connecting apparatus according to the first to fourth embodiments do not need to be particularly independent means. It is only necessary to select a cycle period that satisfies. In the error detection, the same error detection can be performed by detecting the phase difference between the reference cycle period and the cycle period received from the transmission medium. The phase difference can be calculated by the value of the counter at the moment when the cycle start packet is received.

The clock control signal or the cycle control signal shown in each of the first to fourth embodiments is based on the IEEE standard.
Not only transmission by asynchronous packets of the 1394 interface but also transmission by isochronous packets are possible. By transmitting a clock control signal or a cycle control signal using an isochronous packet, the delay time generated during packet transmission is small and fixed, so that more accurate clock and cycle control can be performed. It becomes possible.

Further, the operation of each means shown in each of the first to fourth embodiments can be realized by a CPU and software for realizing the operation of each means. For this reason, even if a recording medium such as a magnetic recording medium or an optical recording medium on which a program for realizing each of the above-described operations is recorded is created and the CPU is operated by using the medium, the above-described embodiment can be implemented. A similar effect can be obtained.

In each of the first to fourth embodiments, the transmission medium connection device, the operation cycle generation device, and the transmission medium connection control device have been described as individual devices. It is also possible to use a device having two or all of the functions of these devices. For example, when the transmission medium connection device has the function of the transmission medium connection control device, it is not necessary to separately connect the transmission medium connection control device.

Further, in each of the above-described first to fourth embodiments, a case has been described in which two transmission media are connected to achieve cycle synchronization. By providing three or more sets of each of the means, the clock control means or the cycle control means, and the control signal transmission means, it becomes possible to connect three or more transmission media to realize cycle synchronization.

[0122]

As described above, in the transmission medium connection device of the first invention, the operation cycle of the transmission medium connection device is compared with the operation cycle of the transmission medium, and the counter of the operation cycle generation device is determined according to the detected error. By transmitting a control signal for increasing or decreasing the value of the transmission medium, the operation cycle of the transmission medium can be synchronized with the operation cycle of the transmission medium connection device.

In the transmission medium connecting apparatus according to the second invention, the operation cycle of one transmission medium among the plurality of connected transmission mediums is compared with the operation cycle of the other transmission medium, and according to the detected error, By transmitting a control signal for increasing or decreasing the value of the counter of the operation cycle generation device, it becomes possible to synchronize the operation cycles of all the connected transmission media.

In the transmission medium connection device of the third invention, the operation period of the transmission medium connection device or the operation period of one transmission medium among a plurality of connected transmission media and the operation period of the other transmission medium And transmitting a control signal for increasing or decreasing the value of the counter of the operation cycle generation device according to the detected error, it becomes possible to synchronize the operation cycles of all the connected transmission media.

In the operation cycle generation device of the fourth invention, the operation cycle is adjusted by increasing or decreasing the counter of the operation clock by the control signal indicating the increase or decrease of the counter received from the transmission medium connection device. The operation cycle generated by the operation cycle generation device can be synchronized with the operation cycle of the transmission medium connection device or another transmission medium.

In the operation cycle generation device according to the fifth invention, the fourth operation cycle
In addition to the operation cycle generation device of the invention of the invention, by controlling by a period for controlling the increase or decrease of the operation clock and the number of clocks to be increased or decreased during the period, the operation cycle is controlled at a uniform rate within this period. Can be adjusted, and in addition to the effect of the fourth aspect, a more stable operation cycle can be generated.

In the transmission medium connection device of the sixth invention, the operation period of the transmission medium connection device is compared with the operation period of the transmission medium, and the operation period generated by the operation period generation device is extended or extended according to the detected error. By transmitting the control signal to be shortened, the operation cycle of the transmission medium can be synchronized with the operation cycle of the transmission medium connection device.

In the transmission medium connection device of the seventh invention, the operation cycle of one transmission medium among the plurality of connected transmission media is compared with the operation cycle of the other transmission medium, and the operation cycle is determined according to the detected error. By transmitting a control signal for extending or shortening the operation period generated by the operation period generation device, it becomes possible to synchronize the operation periods of all the connected transmission media.

In the transmission medium connection device of the eighth invention, the operation period of the transmission medium connection device or the operation period of one transmission medium among a plurality of connected transmission media and the operation period of the other transmission medium And transmitting a control signal for extending or shortening the operation cycle generated by the operation cycle generation device according to the detected error, it is possible to synchronize the operation cycles of all connected transmission media. .

According to the ninth aspect of the present invention, the operation cycle generating apparatus according to the ninth aspect of the present invention measures the operation clock in response to the control signal indicating the extension or shortening of the operation cycle received from the transmission medium connection device, and generates one cycle of the clock when the operation cycle is generated. Change the number,
This makes it possible to adjust the operation period and synchronize the operation period generated by the operation period generation device with the operation period of the transmission medium connection device or another transmission medium.

According to the operation cycle generation device of the tenth aspect, in addition to the operation cycle generation device of the ninth aspect, a period in which the extension or shortening of the operation cycle is controlled, and the extension or shortening is required within the period. By controlling by the number of periods,
The operation cycle can be adjusted at a uniform rate within this period, and in addition to the effects of the ninth aspect, a more stable operation cycle can be generated.

In the transmission medium connection control device according to the eleventh aspect, the connection state of the transmission media mutually connected by the transmission medium connection device is analyzed, and the reference of the operation cycle is selected and notified to the transmission medium connection device. In the transmission medium connection device, in terms of accuracy and time required until synchronization is realized,
It is possible to synchronize the operation cycle of each transmission medium by selecting an optimum operation cycle reference.

It should be noted that any one of the transmission medium connection devices of the first to third inventions, the operation cycle generation device of the fourth or fifth invention, and the transmission medium connection control device of the eleventh invention are used in combination. This makes it possible to synchronize the operation cycles of all transmission media connected to the transmission medium connection device, and to transfer packets and the like transmitted in synchronization with the operation cycle.

Similarly, any one of the transmission medium connection devices of the sixth to eighth inventions, the operation cycle generation device of the ninth or tenth invention, and the transmission medium connection control device of the eleventh invention are used in combination. By doing so, it becomes possible to synchronize the operation cycles of all transmission media connected to the transmission medium connection device, and to transfer packets and the like transmitted in synchronization with the operation cycle.

Furthermore, in the above invention, the operation cycle is changed by the value of the counter, and the value of the counter that generates the operation cycle is adjusted in clock units. The device can be easily configured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of a transmission medium connection device, a transmission medium connection control device, and an operation cycle generation device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a connection state of a transmission medium according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a main configuration of a transmission medium connection device, a transmission medium connection control device, and an operation cycle generation device according to a second embodiment of the present invention.

FIG. 4 is a block diagram illustrating a main configuration of a transmission medium connection device, a transmission medium connection control device, and an operation cycle generation device according to a third embodiment of the present invention.

FIG. 5 is a block diagram illustrating a main configuration of a transmission medium connection device, a transmission medium connection control device, and an operation cycle generation device according to a fourth embodiment of the present invention.

6A is a diagram showing a relationship between cycles of two transmission media when a packet loss occurs. FIG. 6B is a diagram showing a relationship between cycles of two transmission media when a packet needs to be generated.

FIG. 7 is a diagram showing a configuration of a write request packet which is one of asynchronous packets.

FIG. 8 is a diagram showing a configuration of a packet used when transmitting a clock control signal.

[Explanation of symbols]

101, 201, 202, 203, 301, 401, 5
01 transmission medium connection device 102 transmission medium connection control device 103,104,302,303,402,403,5
02,503 Operation cycle generation device 105,106,204,205,206,207,2
08, 209, 210 Transmission medium 107 Period generation means 108 Reference selection means 109, 112 Error detection means 110, 113, 304, 305 Clock control means 111, 114 Control signal transmission means 115 Reference determination means 116 Analysis means 117 Reference notification means 118 , 122 control signal receiving means 119, 123, 406, 407 operation cycle output means 120, 124 counter control means 121, 125 counter 306, 307 counter equalization means 404, 405, 504, 505 cycle control means 506, 507 cycle control uniformity 601 Lost packet 602 Generated packet 701 Write request packet 702 Destination 703 Source 704 Write head address 705 Write size 706 Label 707 rt 708 Type 709 pri 710 802 control period 803 the number of clocks for included data 801 clock control signal packet can

Claims (28)

[Claims] 1. A transmission medium connection device having an operation cycle determined based on the number of operation clocks and connecting a plurality of transmission media operating in synchronization with the operation cycle generated by an operation cycle generation device. A cycle generating means for generating a reference cycle; an error detecting means for detecting an error by comparing the operation cycle of the connected transmission medium with the reference cycle generated by the cycle generating means; A clock control unit that accumulates the error and outputs a clock control signal for increasing or decreasing the operation clock when the magnitude of the accumulated error exceeds a predetermined value; and the operation cycle generation device. And a control signal transmitting means for transmitting the clock control signal. 2. A transmission medium connecting device having an operation cycle determined based on the number of operation clocks and connecting a plurality of transmission media operating in synchronization with the operation cycle generated by an operation cycle generation device. Error detection means for selecting one reference transmission medium from among the connected transmission media, comparing the operation cycle of the reference transmission medium with the operation cycle of the other transmission medium, and detecting an error; A clock control unit that accumulates the error detected by the error detection unit, and outputs a clock control signal for increasing or decreasing the operation clock when the magnitude of the accumulated error exceeds a predetermined value; A transmission signal connection unit for transmitting the clock control signal to the operation cycle generation device of a transmission medium other than the reference transmission medium. 3. A transmission medium connection device having an operation cycle determined based on the number of operation clocks and connecting a plurality of transmission media operating in synchronization with the operation cycle generated by an operation cycle generation device. A cycle generating means for generating a reference cycle serving as a reference for operation; and any one of the operation cycle of the reference transmission medium selected from the connected transmission media or the reference cycle generated by the cycle generating means. Selecting one of the operation cycles,
Error detecting means for detecting an error by comparing with the operation cycle of the connected transmission medium; and when the error detected by the error detecting means is accumulated, and the magnitude of the accumulated error exceeds a predetermined value. Transmission medium for outputting a clock control signal for increasing or decreasing the operation clock, and control signal transmission means for transmitting the clock control signal to the operation cycle generation device. Connection device. 4. The transmission medium connection device according to claim 2, wherein said error detecting means receives an instruction of said operation criterion to be selected, and performs selection based on said instruction. 5. The clock control signal according to claim 1, wherein the clock control signal uses one of an instruction for increasing the clock by one and an instruction for decreasing the clock by one. The transmission medium connection device according to claim 1. 6. The clock control signal according to claim 1, wherein the clock control signal designates a control period for performing a control for increasing or decreasing a clock, and the number of clocks for increasing or decreasing during the control period. The transmission medium connection device according to claim 1. 7. An operation cycle generation device having an operation cycle determined based on the number of operation clocks and connected to a transmission medium that operates in synchronization with the operation cycle generated by the operation cycle generation device. A counter that counts the operation clock; an operation cycle output unit that transmits a reference signal serving as a reference of the operation cycle to the transmission medium when a value of the counter reaches a predetermined value; and an increase or decrease of the operation clock. Control signal receiving means for receiving and outputting a clock control signal instructing the control signal, and counter control means for increasing or decreasing the value of the counter based on the clock control signal received by the control signal receiving means. An operation cycle generation device characterized by the following. 8. An operation cycle generation device having an operation cycle determined based on the number of operation clocks and connected to a transmission medium operating in synchronization with the operation cycle generated by the operation cycle generation device. A counter for counting the operation clock; an operation cycle output means for transmitting a reference signal serving as a reference of the operation cycle to the transmission medium when a value of the counter reaches a predetermined value; and increasing or decreasing the operation clock. A control period for performing control for performing the control, a control signal receiving unit that receives and outputs a clock control signal including a clock number to be increased or decreased during the control period, and measures the control period included in the clock control signal. The counter value is set at regular intervals within the control period based on the number of clocks to be increased or decreased included in the clock control signal. An operation comprising: counter control equalizing means for outputting a counter control signal for increasing or decreasing by one; and counter control means for increasing or decreasing the value of the counter based on the counter control signal. Period generator. 9. The counter control equalizing means controls an increase or decrease of a clock based on the clock control signal received immediately before until a new clock control signal is received. 9. The operation cycle generation device according to 8. 10. A transmission medium connection device having an operation cycle determined based on the number of operation clocks and connecting a plurality of transmission media operating in synchronization with the operation cycle generated by the operation cycle generation device. A cycle generating means for generating a reference cycle; an error detecting means for detecting an error by comparing the operation cycle of the connected transmission medium with the reference cycle generated by the cycle generating means; Cycle control means for accumulating the error, and outputting a cycle control signal for extending or shortening the operation cycle when the magnitude of the accumulated error exceeds a predetermined value; and the operation cycle generation device. And a control signal transmitting means for transmitting the periodic control signal. 11. A transmission medium connection device having an operation cycle determined based on the number of operation clocks and connecting a plurality of transmission media operating in synchronization with the operation cycle generated by the operation cycle generation device. Error detection means for selecting one reference transmission medium from among the connected transmission media, comparing the operation cycle of the reference transmission medium with the operation cycle of the other transmission medium, and detecting an error; Accumulating the error detected by the error detection means, and when the magnitude of the accumulated error exceeds a predetermined value, a cycle control means for outputting a cycle control signal for extending or shortening the operation cycle, A transmission medium connection device, comprising: control signal transmission means for transmitting the period control signal to the operation period generation device of a transmission medium other than the reference transmission medium. 12. A transmission medium connection device having an operation cycle determined based on the number of operation clocks and connecting a plurality of transmission media operating in synchronization with the operation cycle generated by the operation cycle generation device. A period generating means for generating a reference period as a reference for operation; and one of an operation period of a reference transmission medium selected from the connected transmission media or the reference period generated by the period generating means. Error detecting means for selecting one of the operating cycles, comparing the operating cycle of the connected transmission medium to detect an error, accumulating the errors detected by the error detecting means, and calculating the magnitude of the accumulated error. A cycle control unit that outputs a cycle control signal for extending or shortening the operation cycle when the value exceeds a predetermined value; and transmitting the cycle control signal to the operation cycle generation device. Transmission medium connecting device, characterized in that it comprises a control signal transmitter. 13. The transmission medium connection device according to claim 11, wherein said error detecting means receives an instruction of said operation reference to be selected and performs selection based on said instruction. 14. The cycle control signal may use any one of an instruction to extend the cycle by one clock and an instruction to shorten the cycle by one clock as a method of instructing extension or shortening of the cycle. The transmission medium connection device according to any one of claims 10 to 12, characterized in that: 15. The cycle control signal designates a control period for performing control for extending or shortening a cycle, and a number of times for extending or shortening the operation cycle by one clock during the control period. Claims 10-1
The transmission medium connection device according to claim 2. 16. An operation cycle generation device connected to a transmission medium having an operation cycle determined based on the number of operation clocks and operating in synchronization with the operation cycle generated by the operation cycle generation device. A counter that counts the operation clock; a control signal receiving unit that receives and outputs a cycle control signal for instructing extension or shortening of the operation cycle; and a period in which the cycle control signal is not output from the control signal receiving unit. When the value of the counter reaches a predetermined value, a reference signal serving as a reference of the operation cycle is transmitted to the transmission medium, and when the cycle control signal is input from the control signal receiving means, the counter is used. Operating cycle output means for transmitting the reference signal to the transmission medium after or before the value of the reference control signal by a clock included in the cycle control signal. An operation cycle generation device, comprising: 17. An operation cycle generation device having an operation cycle determined based on the number of operation clocks and connected to a transmission medium operating in synchronization with the operation cycle generated by the operation cycle generation apparatus. Receiving and outputting a counter for counting the operation clock, a control period for performing control for extending or shortening the operation period, and a period control signal including the number of times for extending or shortening by one clock within the control period. A control signal receiving unit that measures the control period included in the cycle control signal, and based on the number of times of extension or shortening included in the cycle control signal, sets the operation cycle at a constant interval within the control period by one. Period control equalizing means for outputting a period generation control signal for extending or shortening by a clock, and While the control signal is not being output, when the value of the counter reaches a predetermined value, a reference signal serving as a reference of the operation cycle is transmitted to the transmission medium, and the cycle control equalization means outputs the cycle generation control signal. When a signal is input, an operation period output means for transmitting the reference signal to the transmission medium one or more clocks later or before the value of the counter based on the period generation control signal from a predetermined value, and An operation cycle generation device, comprising: 18. The cycle control equalizing means controls the extension or shortening of the operation cycle based on the cycle control signal received immediately before until a new cycle control signal is received. The operation cycle generation device according to claim 17, wherein 19. A transmission medium connection device that has an operation cycle determined based on the number of operation clocks and connects a plurality of transmission media operating in synchronization with the operation cycle generated by the operation cycle generation device. A transmission medium connection control device, comprising: an analysis unit configured to analyze a connection configuration of the transmission medium; and a reference of the operation cycle when a plurality of the transmission media are operated in synchronization based on an analysis result of the analysis unit. The transmission medium connection control device, comprising: a reference determination unit that determines the operation cycle; and a reference notification unit that notifies the transmission medium connection device of the reference of the operation cycle determined by the reference determination unit. 20. The transmission medium according to claim 1, wherein the transmission medium is a serial bus compliant with IEEE1394.
The transmission medium connection device according to any one of claims 10 to 15. 21. The transmission medium according to claim 7, wherein the transmission medium is a serial bus compliant with IEEE1394.
An operation cycle generation device according to any one of claims 16 to 18. 22. The transmission medium according to claim 1, wherein the transmission medium is a serial bus conforming to IEEE 1395.
10. The transmission medium connection control device according to 9. 23. The transmission according to claim 1, wherein the transmission medium is a serial bus conforming to IEEE 1394, and an isochronous packet is used for transmitting the clock control signal. Medium connection device. 24. The operation according to claim 7, wherein the transmission medium is a serial bus conforming to IEEE 1394, and an isochronous packet is used for transmitting the clock control signal. Period generator. 25. The transmission according to claim 10, wherein the transmission medium is a serial bus conforming to IEEE 1394, and an isochronous packet is used for transmitting the period control signal. Medium connection device. 26. The operation according to claim 16, wherein the transmission medium is a serial bus conforming to IEEE 1394, and an isochronous packet is used for transmitting the period control signal. Period generator. 27. The transmission medium is a serial bus conforming to IEEE 1394, wherein the error detecting means includes a value of a cycle time register at the time of receiving a cycle start packet and a value included in the cycle start packet. The error is calculated by comparing the calculated values.
The transmission medium connection device according to claim 1. 28. A recording medium having recorded thereon a program for causing a computer or a microcomputer to execute a part or all of the functions of the means according to any one of claims 1 to 27.