JPH09261277A - Data transfer system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve data transmission efficiency by temporarily saving fetched data to a memory and securing space in an input buffer unless the space capacitance of an output buffer is lower than data stored in the input buffer. SOLUTION: The input buffer 11 of an input control part 1 stores reception data from an outside and control CPU 12 controls data reception with an external device. The control CPU 22 of an output control part 2 transfer-controls data stored in the input buffer 11 to an output buffer 21 and the output buffer 21 stores data to be outputted to the external device. When a shared memory 23 capable of temporary storing data from the input buffer 21 is provided in the output control part 2 and the space capacitance of the output buffer 21 is lower than data stored in the input buffer, data fetched in the input control part 1 is temporarily saved in the shared memory 21, the space of the input buffer 11 is secured and the reception of the input control part 1 is made to be possible. Thus, the transmission efficiency of large capacitance of data is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication system between CPUs, and more particularly to a large-capacity data communication and a high-speed data communication composed of a shared buffer, two CPUs, a shared memory, and a buffer. The present invention relates to a data communication method between CPUs operating in a field requiring the.

[0002]

2. Description of the Related Art Conventionally, as a data transfer method between CPUs of this type, there is one in which data is transferred between CPUs through a shared memory, for example, the one disclosed in Japanese Patent Laid-Open No. 138749/1993. is there. FIG. 4 is a block diagram showing a configuration of data transfer between CPUs disclosed in the above publication.

The operation of data transfer between the CPUs will be described below. The data transfer method between the CPUs includes a shared memory, an area for transferring data from the CPU 101 to the CPU 102, and a CPU 101 to the CPU 10.
It is divided into an area for data transfer to 2 and a write pointer showing how much data is written in each area and a read pointer showing how much data has been read in each area. However, the other CPU manages the shared memory 103 by updating only the read pointer.

FIG. 5 shows the structure of the shared memory. In FIG. 5, 111 is a read pointer, and 11
Reference numeral 2 indicates a write pointer. FIG. 6 shows the CPU 1.
Data is written from 01 and the CPU 102 reads the data. In FIG. 6, the CPU
When data is transferred from 101 to CPU 102,
First, after the CPU 101 writes to the shared memory 103, the write pointer 112 is moved to the shared memory 1
In 03, updating is performed so as to indicate the last position where the data is written, and the CPU 102 compares the read pointer 111 and the write pointer 112 of the data, and if these values are not equal, the corresponding data Is read, and the read pointer 111 is updated to the same position as the write pointer 112. In the data transfer between CPUs disclosed in the above publication, since the data transfer between CPUs is performed via the shared memory, the addressing is complicated, the CPU is loaded, and the data transfer efficiency is poor. Therefore, it is common to perform data transfer between CPUs by the configuration shown in FIG. 7 in which the shared memory is replaced with a buffer.

The inter-CPU data transfer system of FIG. 7 will be described below. In this data transfer method, an input control unit 201 having an input buffer 211 for storing data from an external data output device and a control CPU 212 for controlling data with an external data output device (not shown); An output buffer 221 that stores data to be output to a device (not shown) and a control CP that performs control to transfer the data stored in the input buffer 211 to the output buffer 221
And an output control unit 202 having a U222.

Next, regarding the operation of this system, a flowchart of the control CPU 212 of the input control unit 201 shown in FIG. 8 and the control CPU 22 of the output control unit 202 shown in FIG.
This will be described with reference to the flowchart of No. 2. Input control unit 20
The control CPU 212 in 1 confirms the buffer flag 216 indicating the storage amount of the input buffer 211 of the input control unit 201, and transmits it to the input buffer 211 of the input control unit 201 from the external data output device in one data transfer. The data is not received until there is a space for the data to be stored (steps S1 and S2 in FIG. 8). Then, as soon as there is a free space in the input buffer 211 of the input control unit 201, the data is transferred to the input buffer 211 (step S in FIG. 8).
3).

On the other hand, the control CPU in the output control unit 202
222 uses the buffer flag 216 of the input buffer 211 of the input control unit 201 and the buffer flag 223 of the output buffer 221 of the output control unit 202 to determine the data storage amount of the input buffer 211 of the input control unit 201 and the output. The free capacity of the output buffer 221 of the control unit 202 is compared (step S1 in FIG. 9). After the free space of the output buffer 221 of the output control unit 202 reaches the data storage amount of the input buffer 211 of the input control unit 201, the control CPU 222 of the output control unit 202 outputs from the input buffer 211 of the input control unit 201. Data transfer is performed to the output buffer 221 of the control unit 202 (step S2 in FIG. 9). After the data transfer between the input buffer 211 and the output buffer 221 is completed, the input buffer 211 of the input control unit 201 can receive the next data.

[0008]

The first problem is that in the conventional data transfer method, when data having a size larger than that of the output buffer is received by the input buffer, the received data is divided into several times and output. This means that the data has to be transferred to the buffer, which reduces the data transfer efficiency.

In the second problem, when the data reception speed of the input control unit is faster than the data transmission speed of the output control unit, the input control unit completes the data reception, but the output buffer of the output control unit does not receive the data. It is possible that the free space does not reach the amount of data accumulated in the input buffer of the data input control unit. Therefore, since the transfer between the input buffer and the output buffer cannot be performed, the input control unit cannot receive the next data, the data reception waiting time becomes long, and the data transfer efficiency decreases.

The third problem is that in order to improve the overall data transfer efficiency, it is necessary to transfer the data received in the input buffer to the output buffer in one data transfer, which is larger than the maximum transmission data amount. Is needed. The reason is that the destination of the data received by the input buffer is only the output buffer.

An object of the present invention is to provide a data transfer method capable of improving the data transmission efficiency when transferring a large capacity of data.

[0012]

According to the present invention, an input controller having an input buffer for storing data from an external data output device and a first control CPU for controlling data reception with the external data output device. And an output buffer for storing the data to be output to the external data output device and outputting the data to the outside, and a second control CP for controlling the transfer of the data stored in the input buffer to the output buffer.
U and an output control unit having a memory capable of temporarily storing data from the input buffer, and when the free capacity of the output buffer is less than the amount of data accumulated in the input buffer, , Temporarily avoiding the data captured in the input control unit in the memory,
There is provided a data transfer method characterized in that a space is secured in the input buffer and reception by the input control unit is enabled.

Further, according to the present invention, when the data received from the outside is transferred from the input control unit to the output control unit, the first control CPU has a buffer flag indicating a storage amount of the input buffer. Thus, it is confirmed whether or not the input buffer has a free space for the data transmitted from the external data output device in one data transfer, and as soon as the free space for the received data or more becomes available,
The data is transferred to the input buffer, and the second control CPU sets a buffer flag of the input buffer,
According to the buffer flag of the output buffer, the data storage amount of the input buffer is compared with the free space of the output buffer, and when the data storage amount of the input buffer is smaller than the free space of the output buffer, the second control C
The PU can obtain a data transfer method characterized by transferring data from the input buffer to the output buffer.

Further, according to the present invention, when the data received from the outside is transferred from the input control unit to the output control unit, the first control CPU has a buffer flag indicating a storage amount of the input buffer. Thus, it is confirmed whether or not the input buffer has a free space for the data transmitted from the external data output device in one data transfer, and as soon as the free space for the received data or more becomes available,
The data is transferred to the input buffer, and the second control CPU sets a buffer flag of the input buffer,
A buffer flag of the output buffer is used to compare the data storage amount of the input buffer with the free space of the output buffer, and when the data reception speed of the input control unit is faster than the data transmission speed of the output control unit, or If the data storage amount of the input buffer is larger than the free space of the output buffer, which occurs when data having a size larger than that of the output buffer is received from the external data output device in the input buffer, CPU for control
Calculates the free space of the output buffer from the buffer flag of the output buffer, transfers the data of the free space of the output buffer from the input buffer to the output buffer, and transfers between the input buffer and the output buffer. After the data transfer is completed, the data transfer destination is switched to the memory, the data remaining in the input buffer is transferred to the memory, and after the data transfer is completed, the second control CPU is Whether there is a free space for the transferred data in the memory is confirmed by the buffer flag of the output buffer, and in the output buffer,
As soon as there is free space for the data transferred from the input buffer to the memory, switching to data transfer between the memory and the output buffer, and transferring the data transferred from the input buffer to the memory to the output buffer A data transfer method characterized by

[0015]

When the free space of the output buffer does not reach the received data of the input buffer at the time of data transfer, the data transfer destination of the input buffer is changed to the memory of the control CPU of the output control unit, and the data is transferred to the control CPU memory. Since the data is temporarily stored, it is possible to secure a free space in the input buffer and start inputting the next data. Therefore, it is not necessary to make the size of the output buffer larger than the maximum size of the transmission data, and it is possible to receive the data even when transferring a large amount of data and reduce the data reception waiting time. The transfer efficiency can be improved as compared with the conventional method.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. The data transfer method according to the present invention comprises an input control unit 1 and an output control unit 2. The input control unit 1 is configured to include an input buffer 11 that stores data received from the outside, and a control CPU 12 that controls data reception with an external device. The output control unit 2 stores data to be output to an external device, and an output buffer 21 that transmits the data to the outside,
The data stored in the input buffer 11 is transferred to the output buffer 2
When the output buffer 21 does not have a free space corresponding to the data received by the control CPU 22 and the input buffer 11, the data from the input buffer 11 of the input control unit 1 is temporarily stored. It also has a memory of the control CPU 22 (hereinafter referred to as a shared memory 23) which is also used for this purpose.

Next, the operation of the embodiment of the present invention will be described. First, in the case of transferring data received from the outside from the input control unit 1 to the output control unit 2, FIG.
This will be described with reference to FIG. Here, FIG. 2 is a flowchart showing an operation in the control CPU 12 of the input control unit 1, and FIG. 3 is a flowchart showing an operation in the control CPU 22 of the output control unit 2. The control CPU 12 in the input control unit 1 confirms by the buffer flag 16 indicating the amount of storage in the input buffer 11 whether the input buffer 11 has a free space for the data transmitted from the external device in one data transfer. (Step S1 and Step S2 in FIG. 2). After that, the data is transferred to the input buffer 11 as soon as the free space equal to or larger than the received data is made in the input buffer 11 (step S3 in FIG. 2). On the other hand, the control CPU 22 in the output control unit 2 uses the buffer flag 16 of the input buffer 11 and the buffer flag 28 of the output buffer 21 of the output control unit 2 to determine the data storage amount of the input buffer 11 and the free space of the output buffer 21. Are compared (step S1 in FIG. 3).

Since the next data transfer method differs depending on the result of the above comparison, first, a case where the data storage amount of the input buffer 11 is smaller than the free space of the output buffer 21 will be described. In this case, the control CPU 22
Data is transferred from the input buffer 11 to the output buffer 21 (step S2 in FIG. 3). After the data transfer between the input buffer 11 and the output buffer 21 is completed, the input buffer 11 can receive the next data.

Next, for example, when the data reception speed of the input control unit is faster than the data transmission speed of the output control unit, or when data having a size larger than that of the output buffer 21 is received in the input buffer 11 from the external data output device. The case where the amount of data stored in the input buffer 11 is larger than the free space of the output buffer 21 that occurs when the above is performed will be described.
The control CPU 22 of the output control unit 2 includes the output buffer 21.
The free space of the output buffer 21 is calculated from the buffer flag 28 of No. 1 and the data corresponding to the free space of the output buffer 21 is transferred from the input buffer 11 to the output buffer 21 (step S3 in FIG. 3). After the data transfer between the input buffer 11 and the output buffer 21 is completed, the data transfer destination is switched to the memory of the control CPU 22, that is, the shared memory 23 (step S4 in FIG. 3). Then, the data remaining in the input buffer 11 is transferred to the shared memory 23 (step S5 in FIG. 3). After the data transfer between the input buffer 11 and the shared memory 23 is completed, the input buffer 11 can receive the data. Input buffer 11
After the data transfer between the shared memory 23 and the shared memory 23 is completed, the control CPU 22 confirms by the buffer flag 28 of the output buffer 21 whether or not there is a free space for the transferred data in the shared memory 23 (step S6 in FIG. 3). ), As soon as the output buffer 21 has a free space for the data transferred from the input buffer 11 to the shared memory 23, the shared memory 2
3 and the data transfer between the output buffer 21 (step S7 in FIG. 3). After that, the data transferred from the input buffer 11 to the shared memory 23 is transferred to the output buffer 21.

[0020]

According to the present invention, even when the data reception speed of the input control unit is faster than the data transmission speed of the output control unit, the data output buffer has a free space for the data received by the input control unit. Since this is not possible, the data reception waiting time is greatly reduced, and the efficiency of data transfer between CPUs can be improved.

Further, according to the present invention, when the free space of the output buffer of the output control unit does not reach the amount of data accumulated in the input buffer of the data input control unit, the data fetched from the input control unit is stored. C for controlling the output controller
Since it is temporarily avoided in the memory of the PU and the free space of the input buffer is secured, it is possible to transfer data of a size larger than the output buffer between the CPUs without a data reception waiting time. As a result, it is possible to provide a communication control device that is excellent in economic efficiency by improving the drawbacks that the conventional data output buffer needs more than the transmission data amount.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a data transfer system of the present invention.

FIG. 2 is a flow chart diagram for explaining a control method of a control CPU of an input control unit in the data transfer system of FIG.

FIG. 3 is a flow chart diagram for explaining a control method of a control CPU of an output control unit in the data transfer system of FIG.

FIG. 4 is a block diagram showing an embodiment of a conventional data transfer system.

FIG. 5 is a diagram showing a structure of a shared memory in a conventional data transfer system.

FIG. 6 is a diagram for explaining a conventional shared memory control method.

FIG. 7 is a block diagram showing another embodiment of the conventional data transfer system.

8 is a flow chart for explaining a control method of a control CPU of an input control unit in the data transfer system of FIG.

9 is a flowchart for explaining a control method of a control CPU of an output control unit in the data transfer system of FIG.

[Explanation of symbols]

 1 Input Control Section 2 Output Control Section 11 Input Buffer 12 Control CPU 13 Control Signal to Input Buffer 14 Control Signal to External Device 15 Received Data 16 Buffer Flag 21 Output Buffer 22 Control CPU 23 Shared Memory 24 to Input Buffer Control signal 25 Control signal to output buffer 26 Data bus 27 Transmission data 28 Buffer flag 29 Control signal to shared memory

Claims (3)

[Claims] 1. An input control section having an input buffer for storing data from an external data output device and a first control CPU for controlling data reception with the external data output device, and data to be output to the external data output device. And a second control CPU that controls the transfer of the data stored in the input buffer to the output buffer, and temporarily stores the data from the input buffer. When the free space of the output buffer is less than the amount of data accumulated in the input buffer, the data fetched by the input control unit is temporarily stored in the memory. The data transfer method is characterized in that the input buffer is vacant and the input control unit can receive the data. 2. When transferring data received from the outside to the output control unit from the input control unit, the first control CPU stores the data in the input buffer by a buffer flag indicating a storage amount of the input buffer. Checking whether there is a free space for the data transmitted from the external data output device in one data transfer, and transferring the data to the input buffer as soon as the free space for the received data or more is made. Then, the second control CPU compares the data storage amount of the input buffer and the free space of the output buffer with the buffer flag of the input buffer and the buffer flag of the output buffer, and the data of the input buffer is compared. When the accumulated amount is less than the free space of the output buffer, the second control CPU moves from the input buffer to the output buffer. 2. The data transfer method according to claim 1, wherein data transfer is performed to the file. 3. When the data received from the outside is transferred from the input control unit to the output control unit, the first control CPU stores in the input buffer a buffer flag indicating a storage amount of the input buffer. Checking whether there is a free space for the data transmitted from the external data output device in one data transfer, and transferring the data to the input buffer as soon as the free space for the received data or more is made. Then, the second control CPU compares the data storage amount of the input buffer with the free space of the output buffer by using the buffer flag of the input buffer and the buffer flag of the output buffer, and the second control CPU of the input control unit When the data reception speed is faster than the data transmission speed of the output control unit, or when the data size is larger than that of the output buffer When the data storage amount of the input buffer, which is generated when the input buffer receives the data from the external data output device, is larger than the free space of the output buffer, the second control CPU causes the buffer of the output buffer. After calculating the free capacity of the output buffer from the flag, data of the free capacity of the output buffer is transferred from the input buffer to the output buffer, after the data transfer between the input buffer and the output buffer is completed, The data transfer destination is switched to the memory, the data remaining in the input buffer is transferred to the memory, and after the data transfer is completed, the second control C
The PU confirms whether or not there is a free space for the transferred data in the memory by the buffer flag of the output buffer, and as soon as a free space for the data transferred from the input buffer to the memory is made in the output buffer. 3. The data transfer method according to claim 1, wherein the data transfer between the memory and the output buffer is switched, and the data transferred from the input buffer to the memory is transferred to the output buffer.