JPH0683289B2 - Communication control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a communication control device, and more particularly to a communication control device of a micro program control system.

[Prior Art] Conventionally, a communication control device of this type includes a first control table in a program control table in which information for controlling a logical channel that is an interface with a host device is stored, and a communication line. The second control table that stores information for controlling the physical channel, which is the interface of the above, is uniquely associated with and the control program does not change at any time. .

Here, the control of the logical channel refers to the control such as receiving a command with the host device and responding to the command without directly accessing the communication line. Further, unlike the above control, the control of the physical channel refers to control of directly accessing a communication line such as transmission / reception of data.

[Problems to be Solved by the Invention] Therefore, the conventional communication control device exists as a unit having both a function of controlling a logical channel and a function of controlling a physical channel in view of the configuration of each control table. There is. So, for example, for a half-duplex line,
Correspondence with the logical channel of the transmission channel or the reception channel of the pair of physical channels, as both the transmission and reception commands are issued only to one preset logical channel of the pair of logical channels. However, there is a drawback that the control program becomes complicated due to the complexity of.

[Means for Solving Problems] A communication control device according to the present invention is connected to a communication line and receives data between a transmission channel for transmitting data to and from the communication line. A physical channel section configured by a pair of physical channels with a reception channel to be performed, and a logical channel configured by a pair of logical channels connected to a host device and having a function of transferring commands and data to the host device. Channel part,
One of the pair of logical channels is uniquely associated with the transmission channel or the reception channel, and data transfer between the communication channel is performed based on a command issued by the host device for each logical channel. A communication control device having a control unit that is performed under the control of a control program, wherein the control unit stores information belonging to the logical channel among information used by the control program for each existing logical channel. A logical channel control table for storing the information belonging to the physical channel among the information used by the control program, the physical channel control table storing each physical channel that exists, and The physical channel in which the command is executed in the logical channel control table. Has a first link pointer pointing to the physical channel control table of the channel, and pointing to the logical channel control table of the logical channel for which the command was issued in the physical channel control table of the physical channel on which the command is executed. The control unit further includes a unit that can change the first and second link pointers at any time.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a communication control device according to an embodiment of the present invention.

The logical channels 11 and 12 are interfaces with a host device, and the transmission channel 13 and the reception channel 14 form a pair of physical channels and are interfaces with communication lines. The control unit 15 has a memory in which a control program is stored, various control tables in which control information as described later is stored, and a processor which controls based on the control program and the control information. To control. The various control tables include a logical channel control table and a physical channel control table as described later.

The command issued from the host device is sent to the control unit 15 through the logical channel 11 or 12. The control unit 15 analyzes and executes this command by the control program, and as a result, the transmission channel 13 or the reception channel 14 and the logical channel 11 are analyzed.
Alternatively, data transfer is performed between 12 or 12.

Here, the data consists of transmission data and reception data. The transmission data flows from the host device to the transmission channel 13, and the reception data flows from the reception channel 14 to the host device.

There are full-duplex lines and half-duplex lines as the types of lines. For full-duplex line, transmission is logical channel 11
Then, the reception is performed on the logical channel 12. In the case of a half-duplex line, both transmission and reception are performed on the logical channel 11.

FIG. 2 is a diagram showing the relationship of the control table at the normal time. The control table 21 is a logical channel control table that stores information that belongs to the logical channel 11, and the control table 22 is a logical channel control table that stores information that belongs to the logical channel 12. The control table 23 is a physical channel control table that stores information that belongs to the transmission channel 13, and the control table 24 is a physical channel control table that stores information that belongs to the reception channel 14. The link pointer 25 in the logical channel control table pointer 21 points to the physical channel control table 23, and the link pointer 26 in the logical channel control table pointer 22 points to the physical channel control table 24. On the other hand, the link pointer 27 in the physical channel control table 23 points to the logical channel control table pointer 21, and the link pointer 28 in the physical channel control table 24 is
Point the logical channel control table pointer 22.

FIG. 3 is a diagram showing the relationship of the control table when executing the command for controlling the reception channel 14 in the case of controlling the half-duplex line. Control tables 31, 32, 33, and
34 is the control tables 21, 22, 23, and 23 of FIG. 2, respectively.
Similar to 24. The link pointer 35 in the logical channel control table pointer 31 points to the physical channel control table 34, and the link pointer 36 in the logical channel control table pointer 32 points to the physical channel control table 33. On the other hand, the link pointer 37 in the physical channel control table 33 points to the logical channel control table pointer 32, and the link pointer 38 in the physical channel control table 34 points to the logical channel control table pointer 31.

When controlling a full-duplex line, the logical channel to which a command is issued is the logical channel 11 for transmission and the logical channel 12 for reception, as described above. Therefore, if the control tables shown in FIG. 2 are linked, the correspondence between the logical channel information in the logical channel control table and the physical channel information of transmission or reception in the physical channel control table can be obtained by following the link pointer. Can be done easily.

On the other hand, when controlling the half-duplex line, the link of the control table may be in the state shown in FIG. 2 as long as it is a command for controlling the transmission channel 13. If it is a command to control the reception channel 14,
The link of the control table is changed from the state shown in FIG. 2 to the state shown in FIG. This makes it possible to easily associate the logical channel information in the logical channel control table with the physical channel information in the physical channel control table, as in the case of the full-duplex line.

[Effects of the Invention] As described above, according to the present invention, the logical channel control table and the physical channel control table are separated, and the correspondence between the two control tables is dynamically changeable. And control of the physical channel can be handled independently, which has the effect of simplifying the control program.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a communication control device according to an embodiment of the present invention, FIG. 2 is a diagram showing a relation of a control table at a normal time, and FIG. 3 is a half-duplex line for controlling a receiving channel. It is a figure which shows the relationship of the control table at the time. 11, 12 …… logical channel, 13 …… sending channel, 14
...... Reception channel, 15 ...... Control section, 21, 22, 31, 32 ......
Logical channel control table, 23, 24, 33, 34 ... Physical channel control table, 25, 26, 27, 28, 35,
36, 37, 38 ... Link pointer.

Claims (1)

[Claims] 1. A pair of physical channels, which are connected to a communication line and configured to transmit data to and from the communication line and a reception channel to receive data from the communication line. Physical channel part,
A logical channel unit that is connected to a host device and is configured by a pair of logical channels having a function of transferring commands and data to and from the host device; one of the pair of logical channels and the transmission channel or Communication having a control unit that uniquely associates a receiving channel and performs data transfer with the communication line under the control of a control program based on a command issued from the host device for each logical channel In the control device, the control unit, among the information used by the control program, information belonging to the logical channel, a logical channel control table for storing each existing logical channel, and information used by the control program Of the physical channels that store the information belonging to the physical channel for each existing physical channel. And a first link pointer that points to the physical channel control table of the physical channel on which the command is executed, in the logical channel control table of the logical channel to which the command is issued, In the physical channel control table of the physical channel to which the command is issued, there is a second link pointer that points to the logical channel control table of the logical channel for which the command has been executed, and the control unit further includes: A communication control device having means for changing the first and second link pointers at any time.