JPS6116106B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an interrupt control method, and more specifically, to a communication control device in a data processing system having a data processing device and a communication control device that controls a line connected to the data processing device. This invention relates to an interrupt control method for a data processing device.

In the data processing system described above, when data is received from the line, if the data has a frame with a normal format and is addressed to the data processing system, conventionally, the communication control device detects this. In any case, the data processing device issues an interrupt request to the data processing device, and the data processing device performs the interrupt processing, runs the communication control program, controls the communication control device, and responds to the line that sent the data. did. However, if the same data frame is repeatedly transmitted due to a fault such as a program runaway in the other device connected to the line, the receiving side generates an interrupt request each time it is received. Generally, interrupts from communication control devices have a high priority, so the data processing device must prioritize the above interrupt processing.
Therefore, the processing capacity of the common processing unit is directed to this interrupt processing, and the capacity of other processing is reduced accordingly.

FIG. 1 is a diagram showing the configuration of a conventional communication control device. In the figure, CCU indicates a communication control unit, and is connected to a common processing unit CPU, a storage device MM, and others of the data processing system via a common bus B by its interface control unit INT-CTL. The common processing unit CPU performs data processing in cooperation with the storage device MM, as well as the communication control unit CCU.
It also controls the lines L ₁ , L ₂ to _Lo accommodated in this communication control unit CCU. In addition, in the communication control unit CCU, LC ₁ , LC ₂ to _{LC o} are lines.
Line connection sections provided for L ₁ , L ₂ to _Lo , L-CTL is a line control section, IO-CTL is an input/output control section, and CM stores control information of the communication control unit CCU. It's memory.

Here, the line connection parts LC ₁ , LC ₂ to _{LC o} are the lines
The line control unit L assembles received characters from data sent from L ₁ , L ₂ , ~L _o , decomposes transmitted characters, and converts signal levels.
- The CTL is equipped with a line scanning circuit, and has a line connection part LC ₁ ,
It is configured to scan LC ₂ to LC _o , detect a character processing request therefrom, and notify the input/output control unit IO-CTL. The input _/ output control unit IO-CTL includes a processor that performs processing based on the control _information in _the control memory CM. It is configured to be able to send an interrupt request signal to the control unit INT-CTL. The data received from the lines L ₁ , L ₂ to _{L o} is sent to the line connection parts LC ₁ , LC ₂ to _{L o} , the line control part L-CTL, the input/output control part IO-CTL, and the interface control part.
Common processing unit via INT-CTL and bus B
The data is transmitted to a data processing device including a CPU storage device MM, and the transmission data from the data processing device is sent to each line via the opposite direction to that described above.

For example, suppose that line connection unit LC ₁ receives data from line L ₁ . If this data has a normal frame structure and is addressed to this data processing system, it is transferred to the input/output control unit IO-CTL via the line control unit L-CTL, where it is identified and an interrupt request signal is sent. to the common processing unit via the interface control unit INT-CTL and bus B.
Send to CPU. The common processing unit CPU receives this interrupt request signal, performs interrupt processing, runs a communication control program, and controls, for example, responding to the line or transferring and storing received data in the storage device MM.

Communication control equipment that configures data links using current HDLC (High Level Data Link Control) procedures uses abnormal frames or frames whose address (destination) is different from its own address (a frame is a frame with a certain flag pattern). It is known to identify the received data (data sandwiched between the two) so as not to cause an interrupt to the common processing unit.

However, with known devices, if a normal frame is received and the address is addressed to itself,
Always causes an interrupt to the common processing unit.

However, if frames that are normal in the data link procedure are repeatedly received in succession due to an abnormal loop or program runaway in the destination device, the known device cannot detect the abnormality in the destination terminal device because the procedure is correct. First, an interrupt is made to the common processing device every time the frame is received. Since an interrupt from a communication control device generally has a high priority, the communication control program is run every time an interrupt occurs. This wasteful processing increases the load on the common processing device, causing problems in that other necessary processing is delayed or impossible.

For example, in the HDLC procedure described above, RR
If a frame such as (receive ready) is sent, no matter how many times this is repeated,
In some cases, it may not be possible to identify an abnormality, and in such a case, the unnecessary frames must be responded to one by one, which may cause the processing capacity of the common processing device to be significantly reduced.

The present invention eliminates the above-mentioned drawbacks of known communication control devices and prevents data loss due to an abnormality in the other device.
Communication that suppresses interrupt request signals to the common processing unit when frames that are correct in the link procedure are repeatedly received, so as not to place an unnecessary load on the common processing unit or reduce its processing capacity. The purpose of this invention is to provide an interrupt control method for a control device.

The present invention is based on the following principle. That is, for example, in a normal case, a monitoring frame such as the above-mentioned RR frame, after sending the frame,
If the data (response) to be received is not sent within a certain time, it is retransmitted, but the time until retransmission is stipulated to be longer than a certain period of time. Generally, when there is no response from the other party and a frame determined by the procedure is to be retransmitted, the time until retransmission is specified. In the present invention, the content of the received frame is stored in a buffer in the communication control device, and when a frame is received within a time shorter than the specified time, this content is compared with the content of the previously received frame. , when they are exactly the same, no interrupt request signal is generated to the data processing device, and when the two frames are different or when the next frame is received after a specified time has elapsed, an interrupt request signal is sent.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a diagram showing an example of the connection configuration of the input/output control unit IO-CTL configured according to the present invention, and this is connected to the input/output control unit IO-CTL of the communication control unit CCU shown in FIG. By adding the above, a communication control device according to the present invention is configured.

In FIG. 2, CP is a character processing unit that performs character processing provided in an input/output control unit of a known communication control device, BM and BM are first and second buffers, respectively, and CRC is a receiving unit. CRC calculation unit, RD- for checking whether data is correct or not
CTL is a reception data control section, COMP is a comparison calculation section, and T is a timer section. Other symbols correspond to FIG.

This will be explained with reference to FIGS. 1 and 2. For example, data received from the line L ₁ passes through the line connection unit LC ₁ and the line control unit L-CTL, and then passes through the character processing unit C-P of the input/output control unit IO-CTL shown in FIG. After that, it is input to the first buffer BM and stored. This content is transferred to the CRC calculation unit CRC, where the CRC checks whether the data stored in the first buffer is correct or not, and the result of this check is notified to the reception data control unit RD-CTL. When it is notified that the received data is correct and positive, the received data control unit RD-CTL sends a signal to the comparison calculation unit COMP to activate it, and also sends an activation signal to the timer unit T. The comparison operation unit COMP is the first and second
It reads and compares the contents of the buffers and notifies the reception data control unit RD-CTL of match/mismatch. When the reception data control unit RD-CTL receives the mismatch signal, it sends out an interrupt request signal, sends it to the common processing unit CPU via the interface control unit INT-CTL and bus B, and also sends the contents of the first buffer BM. Transfer to second buffer BM. The common processing unit CPU receives the interrupt request signal, performs interrupt processing, starts a communication control program, and imports the contents of the second buffer BM into the common processing unit CPU or the storage device MM.

Now, assume that data is received and stored in the second buffer BM as described above. Note that when this data is received first and the reception data control unit RD-CTL is notified that the data is correct by the CRC check, the timer unit T is started as described above, but after the timer unit T is started, the above-mentioned After the prescribed time has elapsed, the signal is sent to the reception data control unit RD-CTL.

Next, when new data is received, processing is performed exactly as described above.

First, the first and second buffer BM and
When the contents of BM are compared and a mismatch is detected, the reception data control section RD-CTL sends out an interrupt request signal, regardless of whether the signal sent from the timer section T after a specified time has already been received or not.

In addition, the first and second buffer BM and
When a match in the contents of BM is detected, that is, when the same data is repeatedly received, when a match signal from the comparison operation unit COMP is received by the reception data control unit RD-CTL. , the reception data control unit RD-CTL identifies whether or not the above-mentioned signal indicating the passage of a specified time from the timer unit T has already been received, and checks that the above-mentioned signal has already been received after the specified time has elapsed. If identified, an interrupt request signal is sent.

However, if it is determined that the specified time has not yet elapsed and the above signal has not been received, the interrupt request signal is not sent.

In this way, if the same frame is received again before the specified time elapses due to an abnormality in the other device, no interruption is made to the common processing device.

In the above, an embodiment has been described in which the input/output control section is provided with means such as the first and second buffers, the comparison operation section and the timer section, etc., in order to achieve the object of the present invention. It can be provided in other parts or locations.

The present invention is not limited to the above embodiments, and can be modified in various ways within its technical scope.

Since the present invention is configured as described above, in a data processing system having a common processing device that controls both a data processing device and a communication control device that controls a line connected to the data processing device, When the other device connected to the line repeatedly sends the same frame before the specified time elapses, this function prevents unnecessary interruptions to the data processing device. This has the effect of preventing a decline in the processing capacity of the common processing device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a conventional communication control device.
FIG. 2 is a connection diagram showing the configuration of an embodiment of the present invention. CPU...Common processing unit, MM...Storage device, B
...Common bus, CCU...Communication control unit, INT−
CTL……Interface control unit, IO-CTL……
Input/output control section, L-CTL...Line control section, LC ₁ ,
LC ₂ ~LC _o ...Line connection section, _L1 , _L2 , ~L _o ...Line, C-P...Character processing section, BM...First buffer, BM...Second buffer, COMP ……
Comparison calculation section, RD-CTL...reception data control section,
CRC...CRC calculation section, T...timer section.

Claims (1)

[Claims] 1. In a data processing system having a data processing device and a communication control device connected to the data processing device, the communication control device has a first buffer for temporarily storing received data, and a first buffer for storing previously received received data. a second buffer to hold, and a first buffer when received data is stored in the first buffer;
and a comparison calculation unit that compares the contents of the second buffer and detects a match, and a timer unit that is activated when the received data is stored in the first buffer and sends out a signal when a predetermined time has elapsed. An interrupt control method characterized in that when the same data as the received data is received again before a predetermined time elapses, an interrupt request to the data processing device is suppressed.