JP2000222317A - Communication controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain efficient data communication capable of confirming the end of DMA transfer at a fixed interval or within fixed time even when communication speeds are different at the time of operating data communication by DMA transfer. SOLUTION: This communication controller is provided with a data table that a communication speed is correspondent to a DMA transfer size. Then, the communication speed is decided, and the DMA transfer size is decided by referring to a data table from the communicating speed. This decided transfer size is set in a DMAC 1-5. Thus, the DMA transfer of data is operated according to the set transfer size to that data communication can be operated by the DMAC 1-5. Therefore, even when the communication speeds are different, the end of the DMA transfer can be confirmed at a fixed interval or within a fixed time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a communication control device, a control method, and a computer-readable storage medium capable of performing data communication by DMA (Direct Memory Access) transfer.

[0002]

2. Description of the Related Art First, a conventional example of this type of communication control device will be described with reference to FIG. Note that the basic configuration of the communication control device is the same as that shown in FIG. 1 described in an embodiment to be described later.
, Ie, CPU1-1,
ROM1-2, RAM1-3, BUS1-4, DMAC
(DMA controller) 1-5, MODEM (modulator / demodulator) 1-6, and NCU (network controller) 1-7 will be partially explained.

FIG. 6 shows a conventional communication control device,
9 is a flowchart illustrating an operation example when performing data communication using MA transfer.

First, in step 6-1, DMAC1-
5 is a step of setting the DMA transfer size to
The A transfer size is always constant regardless of the communication speed.

Step 6-2 is a step for judging whether or not there is a next DMA transfer after the end of the DMA transfer.
If there is the next DMA transfer, the process returns to step 6-1. If there is no next DMA transfer, the process ends.

Due to the above-described operation, the size of the DMA transfer is always constant, so that the end of data transmission / reception cannot be confirmed within a certain interval or within a certain time depending on the communication speed.

[0007]

As described above, in the prior art, when performing data communication by DMA transfer, the size of the DMA transfer is always constant. Another disadvantage is that the end of data transmission / reception cannot be confirmed within a certain time.

Accordingly, the present invention provides a method for performing efficient data communication by confirming the end of a DMA transfer within a fixed interval or within a fixed time, even when data communication is performed by DMA transfer, even if the communication speed is different. It is an object of the present invention to provide a communication control device capable of performing the following.

[0009]

According to the present invention, there is provided a communication control device having a DMAC capable of performing data communication using DMA transfer, a communication speed determining means for determining a communication speed,
Transfer size determining means for determining a transfer size of the DMA from the communication speed; and setting means for setting a transfer size in the DMAC, wherein the transfer size determining means is based on the communication speed determined by the communication speed determining means. The transfer size of the DMA is determined by the above, and by setting the DMA transfer size by the setting means, even if the communication speed is different, the end of the DMA transfer can be confirmed within a certain interval or within a certain time, which is efficient. Data communication can be performed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing a schematic configuration of a communication control device according to one embodiment of the present invention.

In FIG. 1, a CPU 1-1 has a ROM 1
The operation of the entire apparatus is performed based on the programs and data stored in the ROM-2, and the ROM 1-2 stores, for example, a data table as shown in FIG. 2 or a program corresponding to the flowchart shown in FIG. Memory (preset)
It was done.

The RAM 1-3 functions as data exchanged with the DMAC (Direct Memory Access Controller) 1-5 and as a work area for various programs, and the BUS 1-4 is used as a data area between the constituent elements. For sending and receiving.

The DMAC 1-5 controls the DMA transfer between the MODEM (modulator / demodulator) 1-6 and the RAM 1-3.

The MODEM 1-6 modulates the data received from the DMAC 1-5 as appropriate according to the recommendations of the ITU-T, and transmits the modulated data to an NCU (network control unit) 1-7.
The data received from 1-7 is demodulated and transferred to the DMAC 1-5 according to the recommendations of ITU-T.

The NCU 1-7 sends the data from the MODEM 1-6 to the line and modulates the data from the line to the MOD.
EM1-6 receives the call and controls outgoing and incoming calls.

FIG. 2 is an explanatory diagram showing a data table for determining a transfer size from a communication speed according to the present embodiment. This data table has a DMA
The size to be transferred is tabulated and stored in the ROM 1-2. This table data is used in step 4-2 of the flowchart shown in FIG.

FIG. 3 is a diagram of ITU-T Recommendation T.30. FIG. 3 is an explanatory diagram showing an example of a facsimile communication procedure specified in 30.

In FIG. 3, DIS 3-1 is a signal indicating the receiving capability of the receiving device and the like, and includes the communication speed at which the receiving device can receive data.

The DCS 3-2 receives the DIS 3-1 and determines a communication-capable capability from the receiving capability of the receiving device and the transmitting capability of the transmitting device. Yes, and the transmission speed at which transmission is possible is included as data.

The TCF 3-3 is a signal for transmitting dummy data for confirming that there is no communication error at the communication speed indicated by the DCS 3-2. Also, CFR
3-4 is a signal indicating that the dummy data transmitted by the TCF 3-3 has no abnormality.

PIX3-5 is image data to be transmitted, and Q3-6 is a signal indicating that transmission of image data 3-5 has been completed. The MCF 3-7 stores the image data 3
-5 is a signal indicating that the signal has been successfully received. Finally, DCN3-8 is a signal indicating that communication is to be disconnected.

FIG. 4 is a flowchart showing the operation of this embodiment. It is assumed that a program corresponding to this flowchart is stored in the ROM 1-2.

In FIG. 4, in step 4-1 the DI
The communication speed determined from the receivable communication speed in S3-1 and the receivable communication speed of the transmitting device is sent by the DCS 3-2, and the communication speed data of the DCS 3-2 is stored in the RAM 1-3.

In step 4-2, R in step 4-1
ROM based on the communication speed data stored in AM1-3
With reference to the table of FIG.
The MA transfer size is determined and stored in the RAM 1-3.

In step 4-3, R in step 4-2
The DMA transfer size stored in AM1-3 is changed to BUS1-
4, the transfer buffer size is set in the DMAC 1-5.

Step 4-4 is a process for judging whether or not there is the next DMA transfer when the transfer of the buffer set in step 4-3 is completed. The processing shifts to the setting processing of 4-3, and the next D
If there is no MA transfer, the process ends.

In the above operation, step 4-
The time until the end of the buffer transfer in No. 4 is always constant regardless of the communication speed.

FIG. 5 is an explanatory diagram showing where each step (step) shown in the flowchart of FIG. 4 is located in the ROM 1-2. In FIG. 5, 5-1 is step 4
This is an area in which a step of determining a communication speed of -1 is stored.

5-2 is the DMA of step 4-2.
This is an area in which a process for determining a transfer size is stored. Further, 5-3 corresponds to the DMAC1-
5 is an area in which a step of setting a transfer buffer size is stored.

Although the above embodiment has been described with respect to an example in which the steps of the control program are stored in the ROM 1-2 in advance, the storage medium to be stored may be a floppy disk, CD-ROM, hard disk, memory card, or the like. ,
A magneto-optical disk or the like can be used.

Further, a floppy disk, hard disk, memory card, or the like can be used as a recording medium in which both the storage area and the RAM can be rewritten.

Further, the system may be such that a program stored in an external storage medium is appropriately loaded into the apparatus and processed.

In the above embodiment, the transfer size of the DMA is determined from the communication speed with reference to the data table. However, the transfer size may be determined by calculation instead of referring to such a data table. .

In the above embodiment, a facsimile apparatus has been described as an example of a communication control apparatus, but other data communication apparatuses may be used instead of the facsimile apparatus.

[0035]

As described above, according to the present invention,
When data communication is performed by DMA transfer, even if the communication speed is different, the end of the DMA transfer can be confirmed within a fixed interval or within a fixed time, and efficient data communication can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a data table for determining a transfer size from a communication speed according to the embodiment;

[Fig. 3] ITU-T Recommendation T. FIG. 3 is an explanatory diagram showing an example of a facsimile communication procedure specified in 30.

FIG. 4 is a flowchart illustrating the operation of the present embodiment.

FIG. 5 is an explanatory diagram showing a storage state in a ROM of each step in the embodiment.

FIG. 6 is a flowchart showing the operation of the conventional example.

[Explanation of symbols]

 1-1 CPU, 1-2 ROM, 1-3 RAM, 1-4 BUS, 1-5 DMAC, 1-6 MODEM, 1-7 NCU.

Claims (3)

[Claims] 1. A communication control device having a DMAC capable of performing data communication using DMA transfer, comprising: a communication speed determining means for determining a communication speed; a transfer size determining means for determining a DMA transfer size from the communication speed; Setting means for setting a transfer size in the DMAC, wherein a transfer size of the DMA is determined by the transfer size determining means based on the communication speed determined by the communication speed determining means, and the DMA transfer is performed by the setting means. A communication control device for setting a size. 2. A method for controlling a communication control device having a DMAC capable of performing data communication using DMA transfer, comprising: a communication speed determination step of determining a communication speed; and a transfer size determination of determining a DMA transfer size from the communication speed. And a setting step of setting a transfer size in the DMAC. Based on the communication speed determined in the communication speed determining step, a transfer size of the DMA is determined by the transfer size determining step. A method for controlling a communication control device, wherein the DMA transfer size is set. 3. A communication speed determining step of determining a communication speed in a computer-readable storage medium storing a control program of a communication control device having a DMAC capable of performing data communication using DMA transfer; A transfer size determining step of determining a transfer size of the DMAC, and a setting step of setting a transfer size in the DMAC. The transfer size of the DMA is determined by the transfer size determining step based on the communication speed determined in the communication speed determining step. And a control program for determining the DMA transfer size in the setting step.