JPH03248252A - Communication controller - Google Patents

Abstract

PURPOSE:To perform high-speed communication and to relax restrictions on transmission control procedures by providing a communication control part, DMA control part, a character storage part, and a report part to a CPU. CONSTITUTION:When serial data is received from a terminal equipment or the like through a communication line, a communication control part 11 composes characters by parallel conversion, and a DMA control part 11 stores these characters in a main memory 3 of a central processing unit 2. The DMA control part 11 monitors reception characters stored in the main memory 3; and when a characters equal to a prescribed character like ETX, ETB, EOT, ENQ for basic procedures stored in a character storage part 14 is stored in the main memory, an interrupt generating part 13 searches this state to report it to the central processing unit 2 by interrupt. The central processing unit 2 refers to data stored in the main memory 3 to execute a corresponding processing. High-speed communication is possible because reception characters are directly stored in the main memory, and various transmission control procedures such as basic procedures can be adopted.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a communication control system that connects a terminal device at a remote location and a central processing unit via a communication line and controls the exchange of data between the two. It is related to the device.

[Conventional technology]

Conventionally, as a communication control device that supports the functions of assembling and disassembling characters, two configurations have been proposed, as shown in Figures 3 and 4, depending on how received characters are transmitted to the central processing unit. .

When the communication control device 300 in FIG. 3 receives serial data from a terminal device, etc. (not shown) via the communication line 4, it converts the data into parallel data, assembles it into characters, and transfers the data one character at a time to a central processing unit via the bus 303. This is to be sent to W301. In this case, the central processing unit 301
Each time a character from 00 is received, a predetermined process is executed, such as storing the received character in the main memo IJ 302 via the path 304. In addition, in FIG. 3, 305 indicates the communication control device 300 and the central processing bag W301.
It is a signal line that connects this signal! ! Control signals are exchanged between the two devices via 305.

On the other hand, the communication control device 400 in FIG.
1 DMA All 11 part 4002, and the communication line 4
The communication controller 4001 converts the serial data received from
The DMA controller 4002 directly stores the characters in the main memory 402 via the bus 403. In this case, central processing bags! 401 eliminates the need to process the reception of each character, but since the received characters cannot be recognized in real time,
For example, by periodically checking the character storage area of the main memory 402, communication with the communication partner is continued. In addition, in Fig. 4, 404, 40
5 is a central processing unit 401 and a communication control unit 4001. D.M.A.
These are signal lines that connect the control unit 4002, and control signals and the like are exchanged between the two via these signal lines. Also, 4
06 is a signal line connecting the central processing unit 401 and the main memory 402.

[Problem to be solved by the invention]

Conventional communication control devices have the above-described configuration to transmit received characters to the central processing unit, but each has the following problems.

(1) In the communication control device 300 shown in FIG. 3, the central processing unit 301 is required to receive and process each character, and the communication speed via the communication line 4 becomes high.
If the speed of receiving received data becomes faster than the processing speed of 01, the data will be lost. As a result, the communication control device 300 shown in FIG. 3 is not suitable for high-speed communication.

(2) In the communication control device 400 in FIG. 4, high-speed communication is possible because the central processing unit 401 is not used, but as mentioned above, the central processing unit 401 cannot recognize received characters in real time, so the transmission that can be adopted is Control procedures are limited. That is, using a transfer format as shown in FIG. 5(a), the start/stop of text (data) is controlled by a specific character (F"' (7E) xtx),
Although it is easy to apply to HDLC, which employs simultaneous monitoring transmission control based on continuous transmission of a fixed amount of data and continuous response, various transfer formats as shown in Figures 5 (b) to (e) are used. Adopts an alternate monitoring type transmission control that controls data start/stop etc. using multiple characters, divides the data into several blocks, sends them, waits for a normal reception response from the receiving side, and then sends the next block. It is difficult to apply basic procedures that

The present invention has been made in view of the above circumstances, and an object thereof is to provide a communication control device that is capable of high-speed communication and has relaxed restrictions on employable transmission control procedures.

[Means to solve the problem]

In order to achieve the above object, the communication control device of the present invention includes a communication Km unit that controls a communication line, and a DMAflU1 that receives received characters output from the communication control unit and stores them in the main memory of the central processing unit. a character storage section for storing predetermined characters, for example, ETX, ETB, EOT, and ENQ when a basic procedure is adopted; The apparatus includes a notification section that notifies the central processing unit of this fact, for example, by interrupting, when the same character as the character stored in the character storage section is stored.

[Effect]

In the communication control device of the present invention, when serial data is received from a terminal device etc. via a communication line, the communication control section performs parallel conversion and assembles it into characters, and the DMAIIWJ section converts the characters into characters. Store in memory. At this time, the notification section monitors the received characters that are stored, and the ETX, ET stored in the character storage section.
B.EOT.

When a character identical to a character such as ENQ is stored, this fact is notified to the central processing unit by, for example, an interrupt.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, a communication control device 1 according to an embodiment of the present invention includes a communication control section 11, a DMA control section 12, a specific character search interrupt generation section 13, and a specific character storage section 14. ing.

The communication control unit 11 is connected to the communication line 4 and to the central processing unit 2 via a signal line 5 for sending and receiving control signals, etc., and is also connected to the central processing unit 2 via a path 15 for transmitting received characters. 12. This communication control unit 11 is a part that assembles characters for reception and disassembles characters for transmission. In particular, when serial data is received via the communication line 4, it is converted into parallel data, assembled into characters, and the received characters are sent to the DMA control unit 12 via the path 15.

The DMA control unit 12 is connected to the central processing unit 2 via a signal line 6 for sending and receiving control signals, and is connected to the specific character search interrupt generation unit 13 via a path 16 for writing received characters into the main memory 3. It is connected. This D
MAI]? The first unit 12 receives the received characters passed from the communication control unit 11 via the path 15 to the path 16 . Specific character search interrupt generation unit 13. Main memory 3 via bus lO
Store directly in . Note that the storage destination address of the main memory 3 is specified by the central processing unit 2 via the signal line 6.

The specific character storage section 14 is a part that holds specific characters that match the adopted transmission control procedure.

For example, when adopting the basic procedure, the specific character storage section 14 contains hexadecimal values (03), (17), (04) representing each character of ETX, ETB, EOT, and ENQ.
, (05) are stored as shown in the figure, and they are stored as path 1.
7 to the specific character search interrupt generating section 13. Note that the characters are stored, for example, from the central processing unit 2 via the signal line 7.

The specific character search interrupt generating section 13 is connected to the central processing unit 2 via an interrupt signal line 8, and is connected to the central processing unit 2 using a DMA system. 1 part 1
2 through the path 16 to the main memory 3 via the path 10, and constantly monitors the received characters on the path 16 and stores them in the specific character storage section 14. When the same character is stored, an interrupt is sent to the central processing unit 2 via the interrupt signal line 8. Such a specific character search interrupt generation unit 13, as shown in FIG.
It consists of comparators 121 to 124 that compare the specific characters added from the specific character storage section 14 via 7, and an OR circuit 125 that outputs the OR condition signal of the outputs of these comparators to the interrupt signal line 8. can do.

The central processing unit 2 in FIG. 1 also connects the communication control unit 11. In addition to controlling the DMA1il control unit 12, a specific character is stored in the specific character storage unit 14 via the signal line 7, and when an interrupt is generated from the interrupt signal line 8, the data stored in the main memory 3 is stored via the signal line 9. , and perform processing according to the received character.

Next, the operation of the present embodiment configured as described above will be explained using a basic procedure and taking as an example a case where a specific character as shown in the figure is stored in the specific character storage section 14.

When serial data is sent from a terminal device (not shown) through the communication line 4, the data is received by the communication control unit 11 of the communication control device 1, converted from serial to parallel, and sent as characters to the DMA control unit 12. passed to. DM
The A control unit 12 stores this received character in the address of the main memory 3 specified by the instruction from the central processing unit 2 via the specific character search interrupt generation unit 13. At this time, each of the comparators 121 to 124 shown in FIG. In this case, the OR circuit 125 issues an interrupt to the central processing unit 2 via the interrupt signal line 8.

When the central processing unit 2 receives an interrupt, the main memory 3
Refers to the stored data in and executes processing according to the stored data. As a result, ETX, ETB,
When EOT and ENQ are sent, it is possible to recognize them in almost real time and quickly execute necessary processing.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various other additions and changes are possible. For example, the types of characters stored in the specific character storage section 14 are not limited to the above example, and characters that are desired to be immediately recognized by the central processing unit 2 can be stored in accordance with the transmission control procedure adopted. Further, the central processing unit 2 may be notified that the specific character has been stored in the main memory 3 by a method other than an interrupt.

〔Effect of the invention〕

According to the communication control device of the present invention described above, the following effects can be obtained.

- Since the received characters are directly stored in the main memory by the DMA control unit without going through the central processing unit, high-speed communication is possible.

■ If the received character stored in the main memory by the DMA control unit is a preset specific character, for example, ETX, ETB, EOT, ENQ, etc. in the case of the basic procedure, the specific character search interrupt generation unit, etc. Since the notification unit promptly notifies the central processing unit by an interrupt or the like, the central processing unit can quickly execute necessary processing. Therefore, it is possible to employ various transmission control procedures such as the basic procedure.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of the configuration of the specific character search interrupt generation section 13, and FIGS. 3 and 4 are explanatory diagrams and diagrams of a conventional communication control device. , FIG. 5 is a diagram showing an example of a transfer formant. In the figure, 1...Communication control device 2...Central processing unit 3...Main memory...Communication line 1...Communication control unit 2...DMA control unit 3...Specific character search interrupt Generation part 4...Specific character storage part

Claims (3)

[Claims] (1) A communication control unit that controls a communication line, a DMA control unit that receives received characters output from the communication control unit and stores them in the main memory of a central processing unit, and a character storage unit that stores predetermined characters. , a notification unit that monitors received characters stored in the main memory by the DMA control unit, and notifies the central processing unit when the same character as the character stored in the character storage unit is stored; A communication control device including. (2) The communication control device according to claim 1, wherein the notification section notifies the central processing unit by an interrupt. (3) A basic procedure is supported, and ETX, ETB, EOT, and ENQ are stored in the character storage unit.
Or the communication control device according to 2.