JPH04834A - Communication controller - Google Patents

Abstract

PURPOSE:To make it discriminable that from which device a status is transmitted to a bus when the status is monitored by making each device connected to the same bus to add an identifier(ID) number peculiar to each device to the status of each device when each device transmits the status. CONSTITUTION:A value peculiar to a device connected to a token passing bus is set in the device as initialization from an ID number setting switch 24. When the device receives a BOM (a controlling word indicating the commencement of data) thereafter, a driver/receiver 20 sends the BOM to a reception circuit 21. When the device receives an EOM (a controlling word indicating the end of data), the receiver 20 sends the EOM to the circuit 21. The circuit 21 informs a control circuit 25 of the received EOM and a code indicating whether or not a status response is required. The control circuit 25 transmits the content of the ID number setting switch 24 and received results to a received message to a bus as a status when the code indicates that a status response is required.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is applied to a communication control device that is connected to a token passing type bus and performs communication. The present invention relates to a communication control device that can determine a destination device when monitoring status transmitted to a token-passing bus.

〔overview〕

The present invention is a communication control device that is connected to a token-passing bus and controls data communication, which adds an identifier (hereinafter referred to as ID) number unique to each device among the devices connected to the same bus to the status and sends it. This makes it possible to determine from which device the status was sent when monitoring the status sent to the bus.

[Conventional technology]

In the conventional standard token bus system, among the data on the lotus, data to which a special code called a SYNC code is added is treated as a control word. Devices connected to the bus perform transmission based on this control word. Each device connected to the bus has a unique sequence number, and when a control word token with the same value as this sequence number appears on the bus, the corresponding device gains the right to transmit.

If the device that has obtained the right to transmit has data to transmit, it inserts the data between the control word that represents the beginning of the data (hereinafter referred to as BOM) and the control word that represents the end of the data (hereinafter referred to as EOM) and sends the data to the bus. Send.

At this time, a fan code (hereinafter referred to as FC) is added to the BOM to indicate the destination of the data, and when a device connected to the bus detects the BOM, it checks the FC and receives the data it should receive. The data is received after confirming whether the data is the same or not.

A code is attached to the EOM to determine whether or not to return a response to the data reception result, and devices connected to the bus check the EOM after receiving data, and if there is a status response request, a status message is sent. (hereinafter referred to as STA). The STA contains the reception result of the received data and the sequence number possessed by the receiving device.

When a device that has the transmission right completes transmission or has no data to send, it adds +1 to its own sequence number and sends a token onto the bus in order to pass the transmission right to another device.

When the device with the highest sequence number among the devices connected to the bus sends out a token, the next token will not appear on the bus because there is no device with the same sequence number as this token. Then, when the token does not appear on the bus within a specified time (timeout), the device with sequence number 0 obtains the transmission right.

The sequence number is set when the power is turned on or when a reset instruction is issued.

When each device does not receive a token addressed to itself while the token circulates once, that is, from a timeout to the next timeout, that device subtracts its own sequence number by 1. As a result, when a sequence number is missing due to a device failure or the like, the missing number is filled in and the tokens are circulated normally.

Also, when a new token is added to the cycle, such as when the power is turned on, the device waits for a timeout, and uses the sequence number of the token at the time of timeout as the sequence number of its own device.

[Problem that the invention seeks to solve]

As described above, in conventional devices, the sequence number takes different values even for the same device depending on the number of devices when the power is turned on and the order in which the power is turned on. In addition, when a sequence number is missing due to a device failure, etc., each device that has a sequence number larger than the sequence number of the device that was ordered due to the failure will have its sequence number subtracted by 1 to fill in the sequence number. be continuous. Therefore, even if the status transmitted to the bus is monitored by a bus monitor or the like, it is not known which device the status was transmitted from, and this has the disadvantage that it is not possible to efficiently evaluate the device or investigate faults.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and aims to provide a device that, when monitoring a status transmitted to a bus, can determine from which device the status was transmitted.

[Means for solving problems]

A first feature of the present invention is a driver/receiver that is connected to a token-passing bus and that exchanges data with the token-passing bus, a receiving circuit that processes received tokens and data, and a receiver that processes tokens, data, and status. A communication control device comprising a transmission circuit for transmitting data, a data processing circuit for processing transmitted and received data, and a control circuit for controlling each of the circuits, further comprising an ID number setting switch for setting an ID number; means for adding the ID number set by the ID number setting switch to the status, and adding the set ID number to the reception result for the received message when an instruction requiring a status response is received from the token passing method bus. and means for transmitting the status as a status.

The second aspect of the present invention is a driver/receiver that is connected to a token passing bus and that exchanges data with the token passing bus, a receiving circuit that processes the received tokens and data, and a receiving circuit that processes the received tokens and data. ,
and a communication control device comprising a transmission circuit for transmitting status, a data processing circuit for processing transmitted and received data, and a control circuit for controlling each of the circuits, further comprising an ID number storage register for holding an ID number, means for causing the control circuit to store in the ID number storage register an ID number added to an initial setting message transmitted at the time of system initialization; The present invention is characterized in that it includes means for adding an ID number to the status and transmitting it.

It is desirable to provide the ID number in place of the standard status word sequence number.

[Operation] I added to the status when sending the status
A D number is set, and an ID number indicating that the device is unique among devices connected to the same token passing bus is added and transmitted.

It also stores an ID number that is unique among devices connected to the same token-passing bus, which is added to the initial setting message sent when the system is initialized, and stores the ID number that is unique among devices connected to the same token-passing bus. Add a number and send.

Thereby, when monitoring the status transmitted to the bus, it is possible to determine from which device the status was transmitted, and it is possible to efficiently evaluate the device and investigate failures.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

(First Embodiment) FIG. 1 is a block diagram showing the configuration of a first embodiment of the present invention.

The first embodiment of the present invention includes a driver/receiver 20 that is connected to a token passing bus (hereinafter referred to as bus) 10 and exchanges data with the bus 10, and a receiving circuit 21 that processes received tokens and data. and a transmitter circuit 2 that transmits tokens, data, and status.
2, a data processing circuit 23 that processes transmitted and received data, and a control circuit 25 that controls each of the circuits, and further includes an ID number setting switch 24 that sets an ID number. Means for adding the ID number set by the switch 24 to the status, and means for adding the set ID number to the reception result of the received message and transmitting it as the status when receiving an instruction from the bus 10 that requires a status response. including.

Next, the operation of the second embodiment of the present invention configured as described above will be explained.

First, as an initial setting, the ID number setting switch 24 is used to set a unique value among the devices connected to the token passing bus.

Next, when receiving the BOM (control word representing the beginning of data), the driver/receiver 20 transfers the BOM to the receiving circuit 2.
Send to 1. The receiving circuit 21 confirms that the BOM has been received and that the BO
The control circuit 25 is notified of the FC (function code) added to M. The control circuit 25 that receives this notification compares the notified FC with the FC that should be received by its own device, and if they do not match, discards the message. If they match, the message is addressed to the device itself, so the message is received.

Further, when receiving an EOM (control word indicating the end of a message), the driver/receiver 20 transmits the EOM to the receiving circuit 2.
Send to 1. The receiving circuit 21 confirms that the EOM has been received and that the EO
The control circuit 25 is notified of the code added to M indicating whether or not to make a status response. Control circuit 2 that received this notification
5, when the notified instruction has a status response,
The transmitting circuit 22 is instructed to transmit the contents of the ID number setting switch 24 and the reception result of the received message to the bus as a status.

The transmitting circuit 22 transmits the status to the bus via the driver/receiver 20 in accordance with instructions from the control circuit 25. Furthermore, when the instruction is for no status response, the above-mentioned operation is not performed.

(Second Embodiment) FIG. 2 is a block diagram showing the configuration of a second embodiment of the present invention.

The second embodiment of the present invention is connected to a bus 10, and this bus 1
a driver/receiver 20 that exchanges data with 0;
Receiving circuit 21 that processes received tokens and data
, a transmission circuit 22 that transmits tokens, data, and status, a data processing circuit 23 that processes transmitted and received data, and a control circuit 25 that controls each of the circuits, and further includes an ID number that holds an ID number. A storage register 26 is provided, and the control circuit 25 includes means for storing in the ID number storage register 26 an ID number added to an initial setting message transmitted at the time of system initialization, and a means for storing an ID number added to an initial setting message transmitted at the time of system initialization, and a means for storing the ID number when transmitting the status. and means for adding the ID number stored in the storage register 26 to the status and transmitting the status.

Next, the operation of the second embodiment of the present invention configured as described above will be explained.

Communication control device 1 is connected to bus 10 via driver/receiver 20 .

When receiving the initial setting message, the driver/receiver 20 sends this initial setting message to the receiving circuit 21.

The receiving circuit 21 sends the ID number added to the initialization message to the ID number storage register 26. Further, the receiving circuit 21 notifies the control circuit 25 that the initial setting message has been received. The control circuit 25 that received this notification,
Initialize everything in the communication control device 1 other than the ID number storage register 26.

Further, when receiving the BOM' (control signal indicating the beginning of data), the driver/receiver 20 transfers the BOM to the receiving circuit 2.
Send to 1. The receiving circuit 21 confirms that the BOM has been received and that the BO
The control circuit 25 is notified of the FC (function code) added to M. The control circuit 25 that receives the notification compares the notified FC with the FC that should be received by its own device, and if they do not match, discards the message. If they match, the message is received because it is addressed to the device itself.

Next, upon receiving the EOM (control word indicating the end of the message), the driver/receiver 20 transmits the EOM to the receiving circuit 2.
Send to 1. The receiving circuit 21 receives the EQM and the EO.
The control circuit 25 is notified of the code added to M indicating whether or not to make a status response.

Upon receiving this notification, the control circuit 25 selects the number storage register 26 if the notified instruction is a status response.
The transmission circuit 22 is instructed to transmit the contents of the message and the reception result of the received message to the bus as a status.

The transmitting circuit 22 transmits the status to the bus via the driver/receiver 20 in accordance with instructions from the control circuit 25. Furthermore, when the instruction is for no status response, the above-mentioned operation is not performed.

Note that FIG. 3 is a diagram showing the status of the communication control device in the embodiment of the present invention, and FIG. 4 is a diagram showing the status in the conventional example. STA in the figure is a code indicating that this communication data is status.

The status of the conventional device has only the reception result and sequence number added, but the status of the present invention has an ID number set in the position of the sequence number of the conventional device. This ID number is set to a value unique to each device among devices connected to the same bus.

〔Effect of the invention〕

As explained above, according to the present invention, by adding an ID number unique to each device among the devices connected to the same bus to the status, when the status transmitted to the bus is monitored by a bus monitor or the like, It is possible to know from which device the status was sent, which has the effect of making it possible to efficiently evaluate devices and investigate failures.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a first embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of a second embodiment of the present invention. FIG. 3 is a diagram showing the status of the communication control device in the embodiment of the present invention. FIG. 4 is a diagram showing the status of a communication control device in a conventional example. DESCRIPTION OF SYMBOLS 1... Communication control device, 10... Token punching system bus, 20... Driver receiver, 21...
Receiving circuit, 22... Transmitting circuit, 23... Data processing circuit, 24... ID number setting switch, 25...
Control circuit, 26...ID number storage register.

Claims (1)

[Claims] 1. A driver/receiver connected to a token-passing bus and exchanging data with the token-passing bus; a receiving circuit that processes the received tokens and data; A communication control device comprising a transmission circuit that transmits status, a data processing circuit that processes transmitted and received data, and a control circuit that controls each of the circuits, further comprising an identifier number setting switch that sets an identifier number; A circuit includes means for adding an identifier number set by the identifier number setting switch to the status, and a means for adding the set identifier number to the status when receiving an instruction requiring a status response from the token passing bus. 1. A communication control device comprising: means for adding information to a status and transmitting it as a status. 2. A driver/receiver that is connected to the token passing bus and exchanges data with the token passing bus, a receiving circuit that processes the received tokens and data, and a transmitting circuit that transmits the tokens, data, and status. a communication control device comprising: a data processing circuit that processes transmitted and received data; and a control circuit that controls each of the circuits; further comprising: an identifier number storage register that holds an identifier number; means for storing in the identifier number storage register an identifier number added to an initial setting message transmitted at the time of initialization; and means for adding the identifier number stored in the identifier number storage register to the status when transmitting the status. 1. A communication control device comprising: means for transmitting information. 3. The communication control device according to claim 1 or 2, wherein the identifier number is given in place of the sequence number of the standard status word.