JPH088977A - Data communication equipment - Google Patents

Abstract

PURPOSE:To improve efficiency of a buffer and to improve cost performance by optimizing the ratio of an area where the transmission data of the buffer is stored and an area where the reception data is stored according to a communication form. CONSTITUTION:The communication processing part NPU of an optical communication-modem OMOD is provided with two channels as a multiprotocol serial communication interface MSCI and an asynchronous serial communication interface CSIO and is provided with a DMA controller DMAC. The NPU selectively switches the volume ratio of an area to be used as the transmission data buffer TDB of the buffer memory BH of a RAM and an area to be used as a reception data buffer RDB and optimizes the ratio, according to the function or the communication form of a device in use and an opposite device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication device, and more particularly to a technique which is particularly effective when applied to an optical communication modem of an optical communication system using infrared rays as its transmission path.

[0002]

2. Description of the Related Art There is a communication LSI (large-scale integrated circuit device) which has a buffer for temporarily storing transmission data or reception data and is compatible with a plurality of communication protocols. Further, there is an optical communication modem including such a communication LSI and provided as a network interface device of an optical communication system using infrared rays in its transmission path.

A communication LSI provided with a buffer is described, for example, on pages 3 to 6 of "HD64570 SCA Hardware Manual" issued by Hitachi, Ltd. in July, 1990.

[0004]

In the conventional communication LSI or the like described above, the buffer for storing the transmission data or the reception data is, for example, a buffer memory of a random access memory RAM as shown in FIG. BM
It is realized by using an area of a predetermined capacity allocated as This buffer memory BM is an LS for communication.
Regardless of the function and communication form of the optical communication modem including I or the corresponding terminal device, one half thereof is fixed as the transmission data buffer TDB for storing transmission data,
Half the received data buffer RD for storing received data
B. Therefore, for example, when the optical communication modem or the corresponding terminal device is a transmission-only or reception-only device,
A half area of the buffer memory BM is wasted because it is not used at all. As a result, the use efficiency of the buffer memory BM is reduced, and the cost / performance ratio of the optical communication modem and eventually the optical communication system is deteriorated.

An object of the present invention is to improve the use efficiency of the buffer and to improve the cost / performance ratio of the optical communication modem and eventually the optical communication system.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0007]

The outline of the representative one of the inventions disclosed in the present application will be briefly described as follows. That is, in a data communication device such as an optical communication modem equipped with a buffer, the capacity ratio between the area where the transmission data of the buffer is stored and the area where the reception data is stored depends on the function or communication form of the own device or the partner device. In addition to the selective switching, the function and communication form of the own device or the other device is determined by its identification code or by negotiation between both devices.

[0008]

According to the above-mentioned means, the capacity ratio of the area of the buffer in which the transmission data is stored and the area of the buffer in which the reception data is stored can be optimized in accordance with the function or communication mode of the own device or the other device. For example, even when the own device or the partner device is the transmission-only device or the reception-only device, the entire area of the buffer can be used without waste. As a result, the use efficiency of the buffer can be improved, and the cost / performance ratio of the optical communication modem and the optical communication system can be improved.

[0009]

1 is a system configuration diagram of an embodiment of an optical communication system including an optical communication modem to which the present invention is applied. An outline of the configuration and operation of an optical communication system including the optical communication modem of this embodiment will be described first with reference to FIG.

In FIG. 1, the optical communication system of this embodiment is not particularly limited, but has an optical communication network ONW1 which uses infrared rays as its transmission path as its basic constituent element.
This optical communication network ONW1 has an infrared optical communication line O.
Six optical communication modems OMOD are coupled via L, and these optical communication modems OMOD are connected to corresponding terminal devices, that is, personal computers PC1 and PC2, via an RS-232C interface (RS-232C).
The workstations WS1, XY plotter XYP, gateway GW1 and printer PR1 are respectively connected. As a result, these terminal devices are coupled to each other without a physical cable to form one local area network.

In this embodiment, the gateway GW1
Is not particularly limited, but the workstation WS
It is constituted by a terminal device equivalent to, and functions as an interface device with another communication network such as a digital communication network DNW. The other side of the gateway GW1 is connected to the digital communication network DNW via the digital communication line DL.
And the digital communication network DNW is connected to another optical communication network via the digital communication line DL.
It is coupled to the gateway GW2 that constitutes W2. The gateway GW2 is otherwise coupled via an RS-232C interface to a corresponding optical communication modem OMOD, which corresponds to the corresponding optical communication line OMOD.
It is coupled to the optical communication network ONW2 via L. Optical communication network O
Three optical communication modems OMOD are further coupled to the NW2, and RS-23 and RS-23 are connected to these optical communication modems OMOD.
Personal computer P via 2C interface
C3 and PC4 and printer PR2 are respectively coupled.

FIG. 2 is a block diagram of an embodiment of the optical communication modem OMOD included in the optical communication system of FIG. Based on the figure, the optical communication modem O of this embodiment
An outline of the configuration and operation of the MOD will be described. In addition,
The circuit elements forming each block of the optical communication modem OMOD are not particularly limited, but a plurality of integrated circuit devices formed on a plurality of semiconductor substrates with a predetermined combination and configured based on these semiconductor substrates are It is mounted on a common board.

In FIG. 2, the optical communication modem OMOD of this embodiment has a so-called stored program type communication processing unit NPU as its basic constituent element. The communication processing unit NPU includes a multi-protocol serial communication interface MSCI and an asynchronous serial communication interface AS.
CI or clocked serial I / O interface CS
Equipped with two channels that are also used as IO, and DMA (Direct Memory Access) controller DM
Equipped with AC. Among them, the asynchronous serial communication interface ASCI is a corresponding terminal device, that is, the personal computer P via the RS-232C interface.
The clocked serial input / output interface CSIO is coupled to C1 and the like, and is coupled to an EEPROM (electrically erasable / rewritable read-only memory) for storing the operation mode of the optical communication modem OMOD, the identification code ID, and the like. .

On the other hand, the DMA controller DMAC is coupled to the internal bus IBUS of the optical communication modem OMOD, and the internal bus IBUS is not particularly limited, but the read-only memory ROM, the random access memory RAM, the switch SW1 and the peripheral control are further provided. The parts PEC are combined. The peripheral control unit PEC is coupled to the optical modulation / demodulation unit MOD and also includes the switch SW2 and the liquid crystal display unit LED.
And the buzzer BUZ. Further, the multi-protocol serial communication interface MSCI is coupled to the optical modulation / demodulation unit MOD, and this optical modulation / demodulation unit MOD is coupled to the peripheral control unit PEC, and is also coupled to the light emitting unit OT and the light receiving unit OR.

Here, the communication processing unit NPU performs protocol control and communication control according to a control program stored in advance in the read-only memory ROM, and also controls and controls each unit of the optical communication modem OMOD. Further, the read-only memory ROM is composed of a mask ROM or the like having a predetermined storage capacity, and stores control programs and fixed data necessary for protocol control and communication control of the communication processing unit NPU. Furthermore, random access memory RAM
Is composed of a static RAM or the like having a predetermined storage capacity, and is used as a buffer memory BM for temporarily storing transmission data or reception data and a work memory WM as a pointer thereof as described later. Further, the switch SW1 includes a break switch for forcibly stopping the operation of the communication processing unit NPU, a restart switch for restarting the operation, and the like, and the peripheral control unit PEC includes a switch SW2 including a dip switch and a liquid crystal display. LED,
Input / output control is performed between the buzzer BUZ and the optical modulator / demodulator MOD.

On the other hand, the optical modulation / demodulation unit MOD includes a communication processing unit N.
After modulating the transmission data supplied from the PU, the light emitting unit O
The infrared signal UR is output from T to the optical communication network ONW1 and the like, and the received data input from the optical communication network ONW1 and the like via the light receiving unit OR is demodulated, and the communication processing unit NPU
To communicate.

By the way, random access memory RAM
As described above, includes the buffer memory BM in which the transmission data and the reception data are temporarily stored. The buffer memory BM includes the transmission data buffer TDB in which the transmission data is stored and the reception data in which the reception data is stored. It is divided into a data buffer RDB. In this embodiment, as will be described later, the communication processing unit NPU has an area used as a transmission data buffer TDB of the buffer memory BM of the random access memory RAM and a reception data buffer RD.
A function is provided for selectively switching the capacity ratio with the area used as B according to the function or communication mode of the own device or the other device.

FIG. 3 shows a flow chart of the first embodiment of the buffer allocation process of the optical communication modem OMOD of FIG. Further, FIG. 4 shows a conceptual diagram for explaining the buffer allocation process of FIG. Based on these figures,
The outline and the features of the buffer allocation process of the optical communication modem of this embodiment will be described.

The optical communication modem OMOD of this embodiment is provided with the random access memory RAM as described above, and the predetermined area of the random access memory RAM is the buffer memory BM in which the transmission data and the reception data are temporarily stored. Served as. The buffer memory BM has a predetermined capacity, and its storage area is divided into a transmission data buffer TDB for storing transmission data and a reception data buffer RDB for storing reception data. But,
In this embodiment, the communication processing unit NPU of the optical communication modem OMOD is its own device, that is, the optical communication modem OMOD, or a terminal device to which it is connected, or a partner device, that is, the optical communication modem OMOD that is a communication partner, or it is connected to it. It has a function of selectively switching the capacity ratio between the area used as the transmission data buffer TDB and the area used as the reception data buffer RDB of the buffer memory BM according to the function or communication form of the terminal device.

That is, as shown in FIG. 3, the communication processing unit NPU first executes EEPR in step ST11.
The identification code ID of the own device is read from the OM, and in step ST12, the function and communication form of the own device are determined based on the read identification code ID. As a result, when the device is a transmission-only device, the transmission data buffer TDB and the reception data buffer R are processed in step ST13.
Assuming that the DB capacity ratio is 100: 0, the entire area of the buffer memory BM is allocated as the transmission data buffer TDB as shown in FIG. Further, when the own device is the transmission and reception device, the capacity ratio of the transmission data buffer TDB and the reception data buffer RDB is set to 50:50 in step ST14, and the buffer memory BM is set as shown in FIG. The storage area of is divided into the transmission data buffer TDB and the reception data buffer RDB, and is divided into two equal parts. Then, when the own device is set as the reception-only device, the transmission data buffer T
Set the capacity ratio between DB and receive data buffer RDB to 0:10.
As shown in FIG. 4C, the entire area of the buffer memory BM is allocated as the reception data buffer RDB.

On the other hand, a transmission data buffer TDB and a reception data buffer RDB according to the identification code ID of the own device.
The communication processing unit NPU having the capacity ratio of 50:50, at the stage when the partner device is further determined, executes, in step ST16, for example, the EEPR of the optical communication modem OMOD of the partner device.
The identification code ID of the partner device is extracted from the OM via the optical communication network ONW1, and in step ST17, the function and communication form of the partner device are determined based on the extracted identification code ID. As a result, when the partner device is a reception-only device, the transmission data buffer T
The capacity ratio between the DB and the reception data buffer RDB is 100:
As a result, the entire area of its own buffer memory BM is reassigned as the transmission data buffer TDB. If the partner device is a transmission-only device, step ST
By 19, the capacity ratio between the transmission data buffer TDB and the reception data buffer RDB is set to 0: 100, and the entire area of its own buffer memory BM is reallocated as the reception data buffer RDB. When the partner device is the transmission and reception device, the capacity ratio of the transmission data buffer TDB and the reception data buffer RDB remains 50:50.
It is said.

As a result of the above, the optical communication modem O of this embodiment is
In the MOD, the area used as the transmission data buffer TDB of the buffer memory BM and the reception data buffer RD
Since the capacity ratio with the area used as B can be optimized according to the function or communication form of the own device or the other device,
For example, even when the own device or the partner device is a transmission-only device or a reception-only device, the entire area of the buffer can be used without waste. As a result, the use efficiency of the buffer can be improved, and the cost / performance ratio of the optical communication modem and the optical communication system can be improved.

As shown in the above embodiment, the present invention is applied to a data communication device such as an optical communication modem of an optical communication system using infrared rays as its transmission path.
The following effects can be obtained. That is, (1) In a data communication device such as an optical communication modem equipped with a buffer, the capacity ratio between the region in the buffer where transmission data is stored and the region where reception data is stored is defined as the function or communication of the own device or the partner device. The transmission data in the buffer is stored by selectively switching according to the form and determining the function and communication form of the own device or the partner device by its identification code or by negotiating between the two devices. It is possible to obtain the effect that the capacity ratio between the area and the area in which the received data is stored can be optimized according to the function or communication mode of the own device or the other device. (2) According to the above item (1), it is possible to obtain the effect that the entire area of the buffer can be used without waste even when the own device or the partner device is the transmission-only device or the reception-only device. (3) According to the above items (1) and (2), it is possible to improve the efficiency of use of the buffer and increase the cost / performance ratio of the optical communication modem and the optical communication system.

The invention made by the inventor of the present invention has been specifically described based on the embodiments, but the invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say. For example, in FIG. 1, the optical communication system can use optical communication means other than infrared rays as its transmission path. Also, an interface standard other than RS-232C can be used for coupling between each optical communication modem OMOD and the corresponding terminal device. Each of the optical communication modems OMOD may be built in a corresponding terminal device. The optical communication system includes gateways GW1 and GW2.
It is not essential to be coupled to the digital communication network DNW via the network, and it is not necessary to include a plurality of optical communication networks. Furthermore, the network configuration of the optical communication system, the type and number of terminal devices coupled to each optical communication network, the connection format, and the like are not restricted by this embodiment.

In FIG. 2, the optical communication modem OMOD is
The buffer memory BM may include a dedicated random access memory. Also, the communication processing unit NPU
Can have an arbitrary number of channels, and the block configuration and connection format of the optical communication modem OMOD can adopt various embodiments.

3 and 4, step ST14
The capacity ratio between the transmission data buffer TDB and the reception data buffer RDB in can be set arbitrarily according to the transmission rate and the data amount of the own device and the partner device, for example. Further, the determination of the function and communication form of the own device and the partner device can be performed by consultation with the partner device, that is, negotiation, as illustrated in steps ST26 and ST27 of FIG. Transmission data buffer TDB
The capacity ratio of the reception data buffer RDB may be switched by, for example, rewriting a specific bit of the control register. Furthermore, step ST12
Alternatively, the determination of the function and communication form of the own device in ST22 can be performed by hardware using a DIP switch or the like, and the concrete procedure of the buffer allocation process can adopt various embodiments.

In the above description, the case where the invention made by the present inventor is mainly applied to the optical communication modem of the optical communication system which is the background field of application has been described, but the present invention is not limited thereto. For example, it can be applied to various communication systems using a physical cable as a transmission path and data communication devices thereof. INDUSTRIAL APPLICABILITY The present invention can be widely applied to a data communication device including a buffer in which at least transmission data or reception data is stored, and a system including such a data communication device.

[0028]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows. That is, in a data communication device such as an optical communication modem equipped with a buffer, the capacity ratio of the region of the buffer where transmission data is stored and the region where reception data is stored is determined according to the function or communication mode of the own device or the partner device. By selectively switching and determining the function and communication mode of the own device or the other device by its identification code or by negotiating between the two devices, the area where the transmission data of the buffer is stored and the reception data Since the capacity ratio with the area where is stored can be optimized according to the function or communication form of the own device or the other device, for example, when the own device or the other device is a transmission-only device or a reception-only device However, the entire area of the buffer can be used without waste. As a result, the use efficiency of the buffer can be improved, and the cost / performance ratio of the optical communication modem and the optical communication system can be improved.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of an optical communication system including an optical communication modem to which the present invention is applied.

2 is a block diagram showing an embodiment of an optical communication modem included in the optical communication system of FIG.

FIG. 3 is a first buffer allocation process of the optical communication modem shown in FIG.
It is a flowchart which shows an Example.

FIG. 4 is a conceptual diagram for explaining the buffer allocation process of FIG.

5 is a second buffer allocation process of the optical communication modem shown in FIG.
It is a flowchart which shows an Example.

FIG. 6 is a conceptual diagram for explaining buffer allocation processing of the optical communication modem developed by the inventors of the present application prior to the present invention.

[Explanation of symbols]

ONW1 to ONW2 ... optical communication network, OL ... optical communication line, OMOD ... optical communication modem, RS-232C.
..RS-232C interface, DNW ... Digital communication network, DL ... Digital communication line, PC1
-PC4 ... Personal computer, WS ... Workstation, XYP ... XY plotter, PR1
-PR2 ... Printer, GW1-GW2 ... Gateway. NPU ... communication processing unit, MSCI ... multi-protocol serial communication interface, ASCI
..Asynchronous serial communication interface, CSIO ...
・ Clocked serial I / O interface, DMAC
... DMA controller, EEPROM ... Electrically erasable and rewritable read-only memory, IBU
S ... Internal bus, ROM ... Read only memory, RAM ... Random access memory, PEC ...
・ Peripheral controller, SW1 to SW2 ... Switch, LED
... Liquid crystal display, BUZ ... Buzzer, MOD ...
Optical modulation / demodulation unit, OT ... Light emitting unit, OR ... Light receiving unit, U
R ... Infrared signal. TDB ... Transmission data buffer, RDB ... Reception data buffer, WM ... Work memory.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuyoshi Furihata 5-22-1, Kamisuihoncho, Kodaira-shi, Tokyo Inside Hitachi Microcomputer System Co., Ltd. (72) Inventor Junichi Shimizu 5-chome, Mizumizuhoncho, Kodaira-shi, Tokyo 22-1 No. 1 in Hitachi Microcomputer System Co., Ltd. (72) Inventor, Kouji Suzuki, No. 5-22, Kamimizuhoncho, Kodaira-shi, Tokyo Inside Hitachi Microcomputer System Co., Ltd. (72) Masahiro Watanabe Kanagawa Yokohama, Kanagawa 3-12 Moriya-cho, Ward within Victor Company of Japan, Ltd. (72) Inventor Takami Shiramizu 3-12-12 Moriya-cho, Kanagawa Ward, Yokohama City, Kanagawa Within Victor Company of Japan, Ltd.

Claims (4)

[Claims] 1. A buffer having a predetermined capacity for temporarily storing the transmission data or the reception data is provided, and a capacity ratio of the area of the buffer for storing the transmission data and the area for storing the reception data is predetermined. A data communication device characterized by being selectively switched according to conditions. 2. The data communication device according to claim 1, wherein the capacity ratio of the buffer is selectively switched according to the function or communication mode of the own device or the other device. 3. The data communication device according to claim 2, wherein the function and the communication form are determined by an identification code of the own device or the partner device. 4. The data communication device according to claim 2, wherein the function and the communication form are determined by consultation between the own device and the other device.