JPS6282843A - Communication control equipment - Google Patents

Abstract

PURPOSE:To reduce the load of a CPU by arranging a means for checking the station address of a poling or selecting sequence received from a master station in a communication control equipment of a slave station. CONSTITUTION:The address checking part 6 for checking the station address of a poling or selecting sequence received from the master station 1 is arranged in the communication control equipment 4 of the slave station 2 constituted of the device 4 and the CPU 3. When a poling or selection sequence is received by the communication control equipment 4 in the slave station 2 at the transmission of a text, whether the received sequence has a registered station address or not is checked by the checking part 6. When the station address is not yet registered, the sequence is neglected, and when the address has been registered, an interruption is generated in the CPU 3. Since the poling or selecting sequence unrelated to the self station is neglected through the checking part 6 at the reception of the sequence, the load of the CPU 3 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to polling/selecting control means included in a communication control device of a slave station.

〔overview〕

In a communication control device used for a polling and/or selecting system slave station, the present invention generates an interrupt to the central processing unit to perform processing only for the polling sequence and/or selecting sequence related to the local station. This makes it possible to reduce the load on the central processing unit when receiving polling sequences and/or selecting sequences unrelated to the station.

[Conventional technology]

Conventional example of a slave station When the communication control device receives a polling or selecting sequence from the master station, an interrupt is generated from the communication control device to the central processing unit even if it is not a polling or selecting sequence for the own station, and the central processing unit After performing interrupt analysis processing, the communication control device was requested to resume receiving polling and selecting sequences again. In other words, as shown in FIG. 5, the sequence Pol registered in the own station
Even if the polling or selecting sequence other than Pol 1 and Pol 4 is unrelated to the own station, a reception completion interrupt R is generated from the communication control device to the central processing unit each time, and the central processing unit performs the interrupt processing.

[Problem that the invention seeks to solve]

Typically, a single text is several dozen characters long, while polling and selecting sequences are several characters (two or three) long. t if the interrupt to the central processing unit is text.

It occurs after ×n milliseconds, but in the case of polling and selecting sequences it occurs after tl ×3 milliseconds (t+=time required to send and receive one character, n=number of characters). Therefore, the load on the central processing unit required to analyze interrupts from the communication control device is greatest when a small number of characters are continuously received, such as in polling or selecting sequences. Alternatively, the selection sequence also had the drawback of requiring a large load. This drawback becomes more noticeable as the communication speed becomes faster and as the main station's polling transmission interval and selecting retransmission interval become shorter.

The present invention aims to eliminate such drawbacks and to provide a communication control device that can reduce the load on a central processing unit.

Means for Solving Problem c] The present invention is included in a slave station that receives a polling sequence and/or a selecting sequence having a station address from a master station via a communication line, and the communication line and the central processing of this slave station. In a communication control device that is inserted between the communication control device and the communication control device and includes a first control means that generates an interrupt to the central processing unit based on an incoming polling sequence and/or selecting sequence, registration for registering the station address of the slave station. and a second control means for enabling the first control means only for polling sequences and/or selection sequences having a station address that matches the registered station address.

[Effect]

When receiving a polling or selecting sequence from the main station, the communication control device refers to the registration means in which the station address group of its own station is registered, and determines whether the stage address of the received polling or selecting sequence is compatible. If the station address is different from the registered station address, the next polling or selecting sequence is automatically received without interrupting the central processing unit.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block configuration diagram showing the configuration of an apparatus according to an embodiment of the present invention. FIG. 2 is a block configuration diagram showing the configuration of a communication system in which this embodiment device is used. Figure 3 shows the DMA
FIG. 2 is a configuration diagram showing the configuration of a transfer information block management flag, a slave station address group, and a DMA transfer information block (hereinafter referred to as CCB) related to text transmission. FIG. 4 is a sequence diagram showing the operation of this embodiment device.

First, the configuration of this embodiment device will be explained based on FIG. The communication control device 4 includes a slave station 2 connected to the master station 1 via a line 10 in a multipoint manner as shown in FIG.
An address checking unit 6 is included in the communication control unit 4 and is inserted between the line 10 and the central processing unit 3 of the slave station 2 to check the station address of the polling and selecting sequence received from the master station 1. A memory area 7 in which the station address group of the own station is set is provided in the RAM of the station.

A feature of the present invention is that the slave station address group of the own station is stored in the memory area 7, and when a polling or selecting sequence that is not registered here is received, it is ignored and the system returns to reception mode. This means that automatic migration will take place.

Next, the operation of this embodiment device will be explained based on FIGS. 1 to 4.

At the time of initial setting, a plurality of station addresses defined as slave stations 2 are registered in the memory area 7 of the RAM area in the communication control device 4 by the setting unit 5 of the central processing unit 3. Now, when sending a text, please use CCB in advance.
is created and the corresponding bit of the CCB management flag is turned on. When the communication control device 4 receives a polling or selecting sequence, the address checking unit 6 checks whether the station address is registered or not. If the station address is not registered, it is ignored and the next polling or selecting sequence is started. Wait for its arrival. When a registered station address is received, an interrupt is generated to the central processing unit 3. In particular, if the CCB corresponding to the station address is enabled when a polling sequence is received, the text is sent without interrupting immediately, and an interrupt is generated to the central processing unit 3 when a response is received. . Further, the creation of a CCB related to text transmission can be freely performed by the central processing unit 3 asynchronously with the operation of the communication control device 4.

The present invention can also be applied to the case of a slave station having a plurality of station addresses as shown in FIG. This application has a remarkable effect of reducing the burden on the central processing unit.

〔Effect of the invention〕

As explained above, the present invention has the following advantages: By configuring a plurality of slave station address groups within a communication control device,
The effect of making it possible to reduce the load on the central processing unit when receiving polling or selecting sequences unrelated to the own station by equipping the communication control device with a station address check function when polling and selecting sequences are received. There is.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram showing the configuration of an apparatus according to an embodiment of the present invention. FIG. 2 is a block configuration diagram showing the configuration of a communication system in which an embodiment of the present invention is used. FIG. 3 is a signal configuration diagram showing the configuration of the CCB management flag, slave station address group, and CCB in the communication control device. FIG. 4 is a sequence diagram showing the occurrence of an interrupt from the communication control device to the central processing unit in the present invention. FIG. 5 is a sequence diagram showing the occurrence of an interrupt from a conventional communication control device to a central processing unit. FIG. 6 is a block configuration diagram showing the configuration of a slave station having a plurality of station addresses. 1...Main station, 2...Slave station, 3...Central processing unit,
4... Communication control device, 5... Setting section, 6... Address check section, 7... Memory area.

Claims (1)

[Claims] (1) Included in a slave station that receives a polling sequence and/or a selecting sequence having a station address from a master station via a communication line, inserted between this communication line and the central processing unit of this slave station, and incoming polling In a communication control device comprising a first control means for generating an interrupt to the central processing unit based on a sequence and/or a selecting sequence, a registration means for registering a station address of the slave station; and second control means for enabling the first control means only in a polling sequence and/or a selection sequence having a station address.