JPH01289339A - Communication controller - Google Patents

Abstract

PURPOSE:To allow a sender to recognize the reception state of multi-address communication by giving a bit of reply request identifier in a frame as required in a communication controller of a sender for multi-address communication, sending the resulting frame and returning a reply code including at least its own specific address to the sender from an equipment recognizing the identifier. CONSTITUTION:In case of the transmission of multi-address communication, a contention circuit 5 monitors whether or not a code outputted to a transmission circuit 3 is coincident with a code inputted from a reception circuit 4. An equipment except an equipment sending multi-address communication uses a multi-address recognition circuit 6 to detect a frame inputted from the reception circuit 4 and when its own group is designated, a reply code return circuit 9 is controlled to return the reply code. When the frame is received normally, the reply code return circuit 9 returns a reply code 28 while including its own address to the code 28 and in case of detecting any error, the reply code 28 is not returned. Thus, whether or not the equipment to receive the code receives the said frame is confirmed by the sender.

Description

[Detailed Description of the Invention] [Field of Industrial Application] ゛This invention relates to a plurality of communication control devices that are connected to the same transmission path and communicate with each other, and particularly relates to round-trip communication between communication control devices. be.

[Prior Art] FIG. 3 is a block diagram showing a conventional device, in which (1) is a transmission path, and (2a) and (2b).

,...(2m), (2n> are the communication control device, (
12a), (12b), ... (12m).

(12n) are communication control devices (2a>), respectively.

(2b), . . . terminal equipment connected to (2m), (2n), such as various electrical equipment.

FIG. 4 is a format diagram showing the frame format used in the device shown in FIG.
20) is the priority code (abbreviated as PR), (21) is the source address (abbreviated as SA), (22) is the destination address (abbreviated as DA), and (23) is the control code (CC
), (24) is the message length (abbreviated as BC),
(25) is data (abbreviated as DATA), (26) is a frame check code (abbreviated as FCC), (27
) is a dummy code (abbreviated as DMY), (28)
is the response code (ACK/NAK) from the receiving side.
), (29) is a frame.

Next, the operation will be explained. For example, communication control bag Tt (2
When m) sends a frame (29) to the communication control device (2a), enter the self address of the communication control device (2m) in 5A (21), and enter the other party's communication control device (2m) in DA (22). Input the address of 2a), form two frames, and send them on the transmission path (1). Since the transmission line (1) is commonly used by each transmission control device, signal collision may occur on the transmission line (1). Therefore, the communication control device that performs transmission monitors the signal on the transmission path (1), starts transmission when no other signal is present, and during transmission, the signal on the transmission path (1) is its own transmission signal. It monitors whether they match, and when it detects a mismatch, it stops its own transmission to control contention.

In addition, all communication control devices that are not transmitting are connected to the transmission path (1
), and the DA in frame (29)
If (22) matches its own unique address, the frame (29) is addressed to its own station, so this frame (29) is fetched and processed. When the frame (29) is received normally, a response code ACK is sent according to the frame format, and in case of abnormal reception, a response code NAK is sent to the source communication control device (2m).
send it back to

Also, if you perform simultaneous broadcasting from any communication control device to all other communication control devices, or if you have grouped the communication control devices in advance, you can send a message to one or more groups according to the grouping. Broadcast communications (referred to as group broadcasts) can be performed. In the case of such a broadcast communication, a specific bit in the frame (29) indicates that it is a broadcast communication, and the DA (22) specifies all communication control devices or communication control devices of the destination group. ,
Broadcast communication is performed in one frame.

An example of a system that uses such a communication control method is a home bus system, which connects electrical devices in the home to a transmission path via a communication control device, communicates with each other, and controls each electrical device. This is a system for operating and managing the system, and the ``Home Bus System Standard Specification Study Report'' was published by the BI AJ/Radio Association Joint HBS Standards Committee in February 1988. According to the specifications, in the case of broadcast communication, it is stipulated that no communication control device should return a response code. In order to avoid conflicts that occur when multiple recipients attempt to return response codes at the same time in response to broadcast communication, it is convenient to omit returning response codes.

[Problems to be Solved by the Invention] The conventional device is configured as described above, and any communication control device that receives a broadcast communication frame cannot respond under any conditions. Since no code is sent back, there is a problem in that from the perspective of the transmission source communication control device, it is impossible to confirm whether or not the communication control device that should receive the frame has actually received the frame.

The present invention has been made to solve the above-mentioned problems in the conventional devices, and an object of the present invention is to provide a communication control device that returns a response code from a destination communication control device when the return of a response code is requested.

[Means for Solving the Problems] In the present invention, if necessary, a response request identifier bit is inserted into a frame and transmitted in a communication control device that is a transmission source of broadcast communication.

[Operation] The communication control device that recognizes the response request identifier returns a response code that includes at least its own unique address to the sender, so the sender communication control device recognizes the communication control device that has successfully received the broadcast communication. You can know which one.

[Examples] Examples of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing an embodiment of the present invention. In the figure, the same reference numerals as in FIG. 3 indicate the same or corresponding parts.
) is the transmitting circuit, (4) is the receiving circuit, (5) is the competition circuit,
(6) is a broadcast recognition circuit, (7) is a response request identifier recognition circuit, (8> is a broadcast control circuit, (9) is a response code return circuit, (10) is an OR gate, and (11) is a CPU. .

Operations other than broadcast communication are also performed by the third
Since it operates in the same manner as the conventional device shown in the figure, its explanation will be omitted here. FIG. 2 is a format diagram showing the format of a frame used in the present invention in broadcast communication. In the figure, the same reference numerals as in FIG. 4 indicate the same or corresponding parts. )
Assume that the communication is composed of 8-bit codes as shown in (30), (31), and (32) in Figure 2, and the bit indicating that this is a circular communication is b6 of PR (20). Bits (★) are assigned, all bits of DA (22) are used for the bits indicating the destination range of broadcast communication, and the response request identifier is represented by b2 and dot (★) of CC (23). . If the total number of communication control devices connected to the same transmission path (1) is 8 or less, as shown in Fig. 2 (31),
The 8-bit bit number of b7 can be used as an address code. That is, if the unique address number is directed to the third communication control device, the b3 bit is set to logic "1";
The other bits may be set to logic "0".

Using such address codes allows you to specify multiple addresses at the same time. As shown in FIG. 2 (31), if the logic of all 8 bits is set to "1", it indicates broadcast communication with all 8 addresses as destinations.

A communication control device that wishes to transmit a broadcast communication constructs a frame as shown in FIG. 2 and transmits it.

During this transmission, the competition circuit (5) monitors whether the code output to the transmitter circuit (3) and the code input from the receiver circuit (4) match. Communication control devices other than the communication control device that transmits broadcast communications must have a receiving circuit (
If the broadcast recognition circuit (6) detects that the b6 bit of PR (20) of the frame input from 4) is logic "1", and the group to which it belongs is specified in DA (22), , the response request identifier recognition circuit (7) checks whether the b2 bit of the CO (23) is logical "1" or not, and if it is "1", controls the response code return circuit (9) to send the response code. Send it back. Response code return circuit (9)
If the frame is successfully received, the response code (28
) with at least its own address included, and if an error is detected in the received frame, a response code (28) is sent.
If multiple communication control devices do not return response code <28
), a data collision occurs on the transmission path (1), but this can be avoided by the contention circuit (5). If the priority order is set, each communication control device will wait for the response code of the communication control device with a higher priority than its own station to finish returning, and then send back the response code in sequence.

In addition, if the transmission source communication control device does not require a response code for the broadcast frame, if the bit logic of the response request identifier is set to "0", the response code will not be returned and the transmission for the broadcast communication The occupation time of path (1) can be shortened. On the other hand, if you set a rule in advance to always send a response code back to a broadcast frame,
The response request identifier and the response request identifier recognition circuit (7) can be omitted.

In the above description, the self-address is returned as the response code at the time of broadcasting, but the response code may include the self-address at the beginning and other data.

For example, in the case of normal reception, the response code may be an ACK code added after the self address, and when an error is detected in the received frame, the response code may be a NAK added after the own address.

In addition, the broadcast recognition circuit (6) and the response request identifier recognition circuit (
7) etc. have been described as being configured by hardware, but these may also be configured by software of the CPU (11).

[Effects of the Invention] As described above, according to the present invention, - When performing broadcast communication such as simultaneous broadcast or group broadcast, if necessary, a response code that includes at least the own address is returned as a response code. This has the effect that the transmission source communication control device can recognize the reception status of the broadcast communication.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a format diagram showing the frame format used in the device of the present invention, FIG. 3 is a block diagram showing a conventional device, and FIG. 4 is a conventional device. FIG. 3 is a format diagram showing the format of a frame used in the device. 1) is the transmission path, (2a), (2m), and (2n) are each communication control device, (3) is the transmitting circuit, (4) is the receiving circuit, (5) is the competition circuit, and (6) is the rerouting circuit. Recognition circuit, (7)
(8) is a response request identifier recognition circuit, (8) is a broadcast control circuit, (
9) is a response code return circuit. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A plurality of communication control devices are connected to the same transmission path, each communication control device has a unique address, and any one communication control device transmits data to any other communication control device. The communication control device that transmits a frame including the source address and the destination address via the above-mentioned transmission path monitors the collision of signals on the above-mentioned transmission path, and when it detects a collision of signals on the transmission path, it transmits the frame. A communication control device that is equipped with a contention control means for interrupting the above-mentioned frame and whose destination address in the frame matches its own unique address receives the frame, and when the frame is received normally, the communication control device that transmits the message In a communication control device equipped with a response code return means for returning a response code to a communication control device, the communication control device is provided in each communication control device, and one frame is used to send a response code to all other communication control devices or communication control devices grouped in advance. For the purpose of broadcasting to any group(s), a bit indicating that the frame is a broadcast, a destination address bit indicating the destination range of the broadcast, and Broadcast transmission means for inserting and transmitting a response request identifier bit indicating that a response is requested for the broadcast communication, if necessary; If a bit indicating broadcast communication is detected and the destination address bits include the group to which the frame belongs, the frame contains the above response request identifier or the response request identifier is omitted. 1. A communication control device comprising: response code return means for returning a response code including at least its own unique address when there is a rule in advance to request a response even if the communication control device receives a response.