JPH07202860A - Communication controller - Google Patents

Abstract

PURPOSE:To obtain the communication controller whose communication is continuously available even after system changeover by eliminating the need for interrupt and initializing of communication when an active communication controller is replaced by a standby communication controller. CONSTITUTION:All flip-flop circuits 20, 21-2n in circuits being components of the communication controller are connected like a shift register. Input and output terminals 40, 90 of the flip-flop circuits connected like a shift register of the standby system communication controller and input and output terminals 40, 90 of the flip-flop circuits connected like a shift register of the active system communication controller are connected to replace the internal operating state of the communication controllers between the active and standby systems. Thus, the operation at system changeover is taken over.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control device, and more particularly to a layer 2 communication control device which is duplexed by an active system and a standby system and performs system switching at the time of a failure or periodical normality confirmation.

[0002]

2. Description of the Related Art When switching a standby system to an active system in a conventional communication control device, the memory contents of a processor, which is a host device, are taken over, the communication control device is initialized according to the memory contents, and then restarted. I was raising. At the time of this switching transition, processing such as transition to the busy state of the layer 2 state, read / write of the memory in the communication control device by the high-speed data transfer bus between the communication control devices, and read / write of the internal register are performed. There is a need to do.

[0003]

In this conventional communication control apparatus, since the host apparatus initializes various parameters of the communication control apparatus from the memory contents of the host apparatus, it takes time to start the communication control apparatus. is there. Also, in a communication control device having a transmission control procedure, the state of the communication control device on the other side of communication and the state of the active communication control device after system switching conflict with each other due to the initial settings during system switching, and the partner communication control device during system switching However, there is a problem in that it is necessary to perform the initial setting of and to restart communication with the partner communication control device.

[0004]

In order to solve the above-mentioned problems, a communication control device of the present invention is a communication control device which is duplexed by an active system and a standby system. A means for connecting the flip-flop circuits in a shift register form is provided, and the output of the flip-flop circuit connected in the shift register form in the communication control device of one system is connected to the shift register form in the communication control device of the other system. Are connected to the inputs of the flip-flop circuits connected to.

When switching the system configuration, the flip-flop circuits connected in the shift register form are operated as a shift register so that the contents of the flip-flop circuit in the communication control device of one system are communicated with the communication of the other system. It is characterized by being transferred to a flip-flop circuit in the control device.

[0006]

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

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a time chart showing the operation of the embodiment of the present invention.

The communication control device is composed of a logic circuit, and the logic circuit forming the communication control device can be roughly divided into a data holding circuit using a flip-flop circuit and a combination circuit. The operation state of the communication control device is determined by passing the data held in the flip-flop circuit and the held data through the combinational circuit. That is, the operation of the communication control device can be determined depending on what data is held in the flip-flop circuit.

The embodiment of FIG. 1 shows that all the flip-flop circuits are extracted from the logic circuit of the communication control device and a selector is provided at the input of these flip-flop circuits.

The communication control device 1 includes a flip-flop circuit 2
A flip-flop circuit including 0, 21 to 2n and a logic circuit 10 other than the flip-flop circuit.

Selectors 30, 31 to 3n are connected to the input sides of all the flip-flop circuits, and the selectors connect the input signal terminals of the flip-flop circuits when the connection line 50 is "0". Connected to the logic circuit 10 other than the flip-flop circuit (connection lines 60, 61 to 6
n), and when the connection line 50 is "1", it is connected to the output signal terminal of the flip-flop circuit at the preceding stage.

Next, the operation of the communication control device having the above configuration will be described.

The communication control device 1 operates normally when "0" is input to the connection line 50.

When "0" is input to the connection line 50, the selectors 30, 31 to 3n cause the flip-flop circuits 20, 21 to operate.
2n input signal terminals are connected to the logic circuit 2 other than the flip-flop circuit. (Connecting wire 60, 61 to 6n
From the connection line 80, 81 to 8n and outputs the signal. ) By inputting "1" to the connection line 50, all flip-flop circuits in the communication control device 1 are connected to the connection line 40.
Becomes an input and the connection line 80 becomes an output.

The flip-flop circuit 20 corresponds to the first stage of the shift register, and the connection line 40 which is an input from the outside is selected by the selector 30 and connected to the input signal terminal 12 of the flip-flop circuit 20. In the flip-flop circuit 21, the output signal terminal side of the previous flip-flop circuit 20 is selected by the selector 31 and connected to the input signal terminal.

In this way, by selecting the output signal of the front stage of all the flip-flop circuits as the input signal of the rear stage by the selector, all the flip-flop circuits in the communication control device 1 have a shift register configuration.

The final stage flip-flop circuit 2n selects the output signal of the final stage flip-flop circuit (shown in the figure) as the input signal by the selector 3n, and the output signal of the flip-flop circuit 2n is the connecting line 80. Is output to the outside.

At this time, as shown in the time chart of FIG. 2, all the flip-flop circuits in the communication control device 1 are input by inputting clocks for all the flip-flop circuits with "1" being input to the connection line 50. The state of connection 80
, And at the same time, the state is set in all the flip-flop circuits in the communication control device 1 by the signal input from the connection line 40, and the connection line 50 is set to "1". It can be an internal operation state of the communication control device.

FIG. 3 is a block diagram showing the configuration of a duplicated communication control device using the communication control device of this embodiment.

The host device 200 is connected to the connection line 2 as described above.
Communication control device 201 and communication control device 20
The flip-flop circuit is switched to the shift register by sending "1" to the selector in the circuit of No.2.

The communication control device 201 connects the flip-flop circuit in the circuit of the communication control device 201 via a connection line 211 in the form of a shift register to output the output signal of the shift register to the flip-flop circuit in the circuit of the communication control device 202. Input to a shift register configured by connecting the loop circuits in the form of a shift register. The communication control device 202 has a connection line 2
The flip-flop circuit in the circuit of the communication control device 202 is connected to the shift register by way of the output signal of the shift register, and the flip-flop circuit in the circuit of the communication control device 201 is connected in the form of the shift register. Input to the configured shift register.

The connection line 213 is a connection line for connecting the active communication control device of the communication control device 201 or the communication control device 202 and the partner communication control device (not shown).

It is now assumed that the communication control device 201 is the active system and the communication control device 202 is the standby system. At this time, the communication control device 201 is communicating with the partner communication control device (not shown) via the connection line 213.

Here, the host device 200 is the communication control device 2
When the communication control device 202 is switched to the standby system 01 and the communication control device 202 is switched to the active system, the host device 200 transfers the contents of the flip-flop circuit in the circuit of the communication control device 201 via the connection line 210 to the communication control device via the connection line 211. The transfer is instructed to the flip-flop circuit in the circuit 202.

Since the communication control device 202 which has become the active system due to the system switching has input the data of the flip-flop circuit of the communication control device 201 which has been the active system until immediately before through the connection line 211, the operating state is exactly the same as that of the communication control device 201. The partner communication control device connected via the adjacent connection line 213 can continue communication even after the communication control device is switched from the communication control device 201 to the communication control device 202 before and after the system switching.

[0026]

As described above, the communication control device of the present invention includes means for connecting all flip-flop circuits of the circuits constituting the communication control device in a shift register form and all flip-flops connected in a shift register form. Since the circuit has a means for inputting and outputting a signal as a shift register, when the communication control device at the time of duplex operation of the active system and the standby system is switched from the standby system to the active system, the active system communication is performed. It is possible to move the internal operating state of the control unit to the internal state of the standby system communication control unit, and there is no need to make an initial setting for the operating state of the communication control unit of the other party of communication, so the communication remains as it was before the system switchover. This has the effect that system switching can be continued and efficient.

Further, in the case of the communication control device having the transmission control procedure, the state of the communication control device of the communication partner and the state of the active communication control device after the system switchover coincide with each other. There is also an effect that setting is unnecessary, the state of the transmission control procedure with the partner communication control device can be continued, and restart of communication is unnecessary.

[Brief description of drawings]

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

FIG. 2 is a time chart showing the operation of the embodiment of the present invention.

FIG. 3 is a block diagram showing the configuration of a duplicated communication control device using the communication control device of the present invention.

[Explanation of symbols]

1 Communication Control Device 10 Logic Circuit Other Than Flip-Flop Circuit 20, 21-2n Flip-Flop Circuit 30, 31-3n Selector 40 Connection Line (Input) 50 Connection Line (Selector Control) 60, 61-6n, 80, 81-8n Connection line (connection path with logic circuit other than flip-flop circuit) 70, 71 to 7n Connection line (trigger input of flip-flop circuit) 90 Connection line (output) 200 Upper device 201, 202 Communication control device 210, 211, 212 , 213 connection line

Claims (1)

[Claims] 1. A communication control device comprising a dual system of an active system and a standby system, comprising means for connecting all flip-flop circuits of the communication control device in a shift register form, and communication control of one system. The outputs of the flip-flop circuits connected in the shift register shape in the device are respectively connected to the inputs of the flip-flop circuits connected in the shift register shape in the communication control device of the other system, and when switching the system configuration, A flip-flop circuit connected in the form of a shift register is operated as a shift register to transfer the contents of the flip-flop circuit in the communication control device of one system to the flip-flop circuit in the communication control device of the other system. Communication control device.