JPH06164647A - Data transmission controller - Google Patents

Abstract

PURPOSE:To transmit data at high speed by DMA control even in a basic (BSC) sequence. CONSTITUTION:A transmission/reception control part 2 is provided with a DMA control part 10, detection part 12 for detecting control signals showing the start and end of communication, and DMA control start/end control part 13 for controlling the start and end of DMA control at the DMA control part 10. In the case of transmission, a transmitting frame 14 is stored in a memory 1, and the DMA control part 10 extracts the transmitting frame stored in the memory 1 and transfers it to a transmission/reception part 3 by DMA control. In the case of reception, the DMA control start/end control part 13 starts the DMA control based on the detecting signal detected by the detection part 12, the DMA control part 10 stores a received frame in the memory 1 under the DMA control, and the DMA control start/end control part 13 ends the DMA control of the DMA control part 10 based on the detection of OFF of the control signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission control device for performing data transmission in a data communication system such as ISDN by DMA control.

When data transmission control is performed by DMA control in a data communication system, a DMA control is used for a high level data link control procedure (HDLC) which is structured so that the start and end of a frame can be identified by flags. It can be done easily. However, when various types of transmission control codes (TCC) are added to the start and end of a frame like the basic procedure (BSC), it is difficult to control transmission by DMA control.

It is an object of the present invention to provide a data transmission control device for performing high-speed data transmission processing by DMA control so that the data transmission control device according to the BSC procedure can be applied to a high speed data communication system such as ISDN.

[0004]

2. Description of the Related Art FIG. 4 shows a conventional BSC procedure data transmission controller. In the figure, reference numeral 50 is a data transmission control device, and 51 is a memory for storing transmission data and reception data. Reference numeral 52 denotes a transmission / reception control unit which controls the transmission data of the memory 51 by the transmission / reception program of the BSC procedure, transfers the transmission data to the transmission / reception unit 53, and stores the data received by the transmission / reception unit 53 in the memory 51. . 53 is a transmitting / receiving unit,
Transmission data transmitted from the transmission / reception control unit 52 is output to another data transfer control device via a network, and data transmitted from another data transmission control device is received and transferred to the transmission / reception control unit 52. Is. 5
Reference numeral 4 is a transmission / reception program of the BSC procedure, which extracts text data to be transmitted from the memory 51 and attaches a transmission control code of the BSC procedure to create transmission data in a frame unit (hereinafter referred to as transmission frame) The text data is separated from the unit reception data (hereinafter referred to as a reception frame) and stored in the memory 51. Reference numeral 55 denotes a frame creation unit, which adds a transmission control code of the BSC procedure to the text data retrieved from the memory 51 to create a transmission frame. 56
Is a text data separation unit that separates and extracts text data from the received frame.

The operation of data transmission with the configuration shown in the figure will be described later. FIG. 5 shows a configuration example of a frame. In the figure, (a)
Is an example of a frame in the HDLC procedure.

In the figure, 60 is a frame. F is a flag and represents the start and end of the frame. AC is an address control signal for designating a device address and the like. The text data represents the text of data to be transmitted / received. FCS is a series of bits that detect errors in the transmitted signal.

The transmission frame of the HDLC procedure is always provided with a flag F indicating the start and end of the frame as shown. (b) is an example of a frame of the BSC procedure.

Reference numerals 61, 62 and 63 are frames. In each frame 61, 62, 63, SYN is a transmission control code for synchronizing the frames. ST
X is a transmission control code that specifies the start of text data. CRC is a check bit of data. ETX
Is the code that represents the end of the text. SOH is a transmission control code for instructing the start of the header. ETB is a transmission control code that specifies the end of the block.

The transmission frame 61 starts with SYN and then ST
X is followed by text data and CRC, and ends with ETX. The transmission frame 62 starts with SYN, STX is followed by text data and CRC, and ends with ETB. The transmission frame 63 starts with SOH, followed by STX, followed by text data and CRC, and ends with ETB.

As shown in the figure, in the BSC procedure, the transmission control codes at the beginning and end of the transmission frame differ depending on the frame and are not constant. The conventional BS shown in FIG. 4 described above.
The operation of the data transmission control device in the C procedure will be described.

When transmitting data, the transmission / reception control unit 52
Extracts the text data from the memory 51 according to the response signal from the data transmission device on the receiving side. Then, the frame creation unit 55 adds a transmission control code to the text data and creates a transmission frame. The transmission / reception control unit 52 transfers the transmission frame to the transmission / reception unit 53. The transmitting / receiving unit 53 outputs the transmission frame to the receiving side via the network.

When receiving, a frame (reception frame) transmitted from the transmission side according to the response is transmitted / received by the transmission / reception section 53.
To receive. In the transmission / reception control unit 52, the text data separation unit 56 separates the text data according to the transmission control code of the received frame. The transmission / reception control unit 52 stores the separated text data in the memory 51.

FIG. 6 shows an example of a data transmission method according to the BSC procedure. In the figure, A is a transmitting side and B is a receiving side. Communication consists of each phase of line connection, information transmission, termination processing, and line disconnection.

The data transmission procedure will be described according to the numbers shown. (1) The carrier signal is transmitted from the transmitting side to the receiving side. (2) The sending side is SA (communication partner designation code), UA (output device designation code), ID (sender side ID code), E
Send NQ (response request from the other party).

(3) The receiving side has DLE (transmission control extension),
Returns ACK (output device is ready). (4) The transmitting side sends a frame consisting of the transmission control codes SOH (heading start) and H (heading).

(5) Further, the transmission side has a transmission control code S
Text data, ET along with TX (start of text)
A frame consisting of B (end of transmission block) is transmitted. (6) The receiving side returns DLE and ACK upon successful reception.

(7) The transmitting side sends a frame consisting of the control signal STX, text data, and ETX. (8) The receiving side returns DLE and ACK upon successful reception.

(9) The transmitting side has EOT (end of transfer), EO
Returns T. (10) The receiving side returns EOT and EOT. (11) The transmitting side returns DLE and EOT.

(12) The receiving side returns DLE and EOT. (13) Disconnect the line.

[0020]

Since the conventional data transmission control device according to the BSC procedure carries out the transmission frame creation, the reception frame processing, the frame transfer, etc. by the program processing, the conventional data transmission control device according to the BSC procedure is It was difficult to apply to high-speed communication systems such as ISDN.

Further, although it is possible to perform high-speed data transfer processing by the DMA control, it is possible to easily perform the DMA control when the start and end of the frame can be identified by the flag as in the above-mentioned HDLC procedure. Is easy. However, in case of BSC procedure, SOH, STX, S
A frame is started with various transmission control codes such as YN, and various transmission control codes such as ETX and ETB are used to end the frame.

Therefore, in the BSC procedure, it is difficult to identify the start and end of a frame, the device must be configured in all cases, and it is difficult to perform high-speed data transmission by DMA control. Was that.

The present invention allows the DMA even in the BSC procedure.
An object of the present invention is to provide a data transmission control device capable of high-speed data transmission by control.

[0024]

The present invention utilizes a control signal such as a carrier signal or an I-line signal to start a frame,
Detecting the end and enabling high-speed data transmission by DMA control.

FIG. 1 shows the basic configuration of the present invention. (a) is the device configuration. In the figure, reference numeral 1 is a memory for storing the frame data constituting the transmission frame 14 or the reception frame 14. A transmission / reception control unit 2 transmits / receives frame data according to the BSC procedure under DMA control. Reference numeral 3 denotes a transmission / reception unit, which outputs a transmission frame to another data transmission control device via the network and is sent from another data transmission device via the network (reception frame)
Is received and transferred to the transmission / reception control unit 2.

In the transmission / reception control unit 2, a DMA control unit 10 takes out a transmission frame from the memory 1 by DMA control, transfers it to the transmission / reception unit 3, and stores the reception frame transferred from the transmission / reception unit 3 in the memory by DMA control. To be stored in. A counter 11 counts the number of data to be DMA-transferred in the DMA control. A detector 12 detects a control signal such as a carrier signal or an I-line signal. A DMA control start / end control unit 13 instructs the DMA control unit 10 to start DMA control when a control signal such as a carrier signal detected by the detection unit 12 is turned on, and is turned off when a control signal such as a carrier signal is turned off. This is an instruction to end the control.

In the memory 1, 14 is a transmission frame (frame data to be transmitted) or a reception frame (frame data to be received).

[0028]

1 (b) shows an operation time chart of the basic configuration of the present invention. In the figure, (1) is a transmission control code for starting data reception, and is a transmission control code for BSC procedures such as SYN and STX. (2) is a DMA control start / end signal. The DMA control start / end signal is, for example, a carrier signal for the V interface and an I line signal or the like for the X interface.

The operation of the configuration shown in the figure will be described. [For Transmission] The transmission frame 14 is stored in the memory 1. The transmission frame 14 is composed of, for example, STX, data (text data), ETX, and the like.

The DMA controller 10 takes out the transmission frame 14 and transfers it to the transceiver 3. The counter counts the number of bytes of the transmitted transmission frame. For example, the DMA control transfer is terminated when the value of the counter is reduced by 1 every time 1 byte is transferred and becomes 0.

[In the case of reception] When the detection unit 12 detects a control signal such as a carrier signal, the detection unit 12 notifies the DMA control start / end control unit 13. The DMA control start / end control unit 13 instructs the DMA control unit 10 to start the DMA control of the received data by the notification from the detection unit 12. And the transmitter / receiver 3
Is frame data such as SYN or STX (received frame)
When receiving, the transmitting / receiving unit 3 transfers the received frame to the DMA control unit 10. The DMA control unit 10 stores the received frame transferred from the transmission / reception unit 3 in the memory 1 by DMA control.

According to the present invention, even in the BSC procedure, D
High-speed data transfer can be performed by MA control.
Therefore, according to the present invention, it becomes possible to perform high-speed data transmission by the BSC procedure in a high-speed communication system such as ISDN.

[0033]

FIG. 2 shows the configuration of an embodiment of the present invention. In the figure, 21 is a memory for storing a transmission frame 42 and a reception frame 43. Reference numeral 22 is a transmission / reception control unit, and 23 is a transmission / reception unit.

In the transmission / reception control unit 22, 31 is a DMA
A control unit, 31 'is a counter, 32 is a detection unit, 33
Is an AND circuit. 34 is MPU (DMA control start
An end control unit) which performs communication control, DMA control start / end control, creation of a transmission frame, and the like. 41
Is a transmission frame creation unit, which creates a transmission frame of the BSC procedure by the transmission control code and the text data.

In the memory 21, reference numeral 42 denotes a transmission frame, which is frame data to be transmitted, and is constituted by STX, text data, ETX and the like. Reference numeral 43 denotes a received frame, which is received frame data and is constituted by SOH, text data, ETX and the like.

FIG. 3 is a diagram for explaining the operation of the embodiment of the present invention (showing the case where it is applied to the V interface). In the figure, (1) is a reception signal (RD), and ON indicates data reception. (2) is a CD signal, and ON indicates reception of a carrier.

The operation of the configuration of FIG. 2 will be described with reference to FIG. [In the case of transmission] The transmission frame creation unit 41 uses the MPU 34
The transmission frame 42 is created under the control of and is stored in the memory 21. The MPU 34 activates the DMA control unit 31.
When the MPU is instructed to start the DMA control, the DMA control unit 31 takes out the transmission frame 42 from the memory 21 and transfers it to the transmission / reception unit 23. The transmitter / receiver 23 is the DMA controller 3
The transmission frame transferred from 1 is output to the receiving side. Then, in the DMA control unit 31, the counter 3
1'counts the number of transmission data of the transmission frame, detects the end of the transmission frame, and ends the DMA control.

[In case of reception] The CD signal (CD signal (2) in FIG. 3) is input to the transmitting / receiving unit 23. And
The carrier-on control signal is input to the AND circuit 33. On the other hand, the AND circuit 33 is connected to the D
Since the ON control signal indicating that the MA control unit is being activated is input, ON of the carrier signal is input to the MPU (34) as a signal indicating the start of DMA control. MPU (34)
Is notified that the carrier signal is turned on, the DMA control unit 31
To start DMA control. Subsequently, when the reception frame is input to the transmission / reception unit 23, the DMA control unit 31 detects that the reception frame is input by the transmission control code (SYN etc.), and stores the reception frame in the memory 21 by DMA transfer. To do. Further, the DMA control unit 31 stores the further received frame in the memory 21 by DMA transfer.

When the transmission from the data transmission device on the transmission side is completed and the carrier signal is turned off, the carry-off is notified to the MPU (34) via the control signal detection section 32. Therefore, the MPU (34) uses the DMA controller 31
To end the DMA transfer, and the DMA control unit 31
Control ends.

[0040]

According to the present invention, the basic procedure (BS
In the C procedure), high-speed data transmission can be performed by the DMA control. Therefore, a high-speed transmission can be performed by applying a data transmission device that performs data transmission according to the conventional basic procedure to a high-speed network system such as ISDN.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of the present invention.

FIG. 2 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 3 is an operation explanatory diagram of the embodiment of the present invention.

FIG. 4 is a diagram showing a data transmission control device of a conventional BSC procedure.

FIG. 5 is a diagram showing a configuration example of a frame.

FIG. 6 is an example of a data transmission method according to the BSC procedure.

[Explanation of symbols]

 1: memory 2: transmission / reception control unit 3: transmission / reception unit 10: DMA control unit 12: detection unit 13: DMA control start / end control unit

Claims (4)

[Claims] 1. A memory (1), a transmission / reception control unit (2) and a transmission / reception unit (3) are provided, and the data stored in the memory (1) is transmitted to another data transfer control device in frame units, and In the data transmission control device that stores the received data transmitted in frame units from the data transmission control device in the memory (1), the transmission / reception control unit (2) detects the start and end of communication with the DMA control unit (10). DM for controlling the start and end of the DMA control of the DMA control unit (10) based on the start and end timings of the communication detected by the detection unit (12) and the detection unit (12)
A control start / end control unit (13) is provided, and in transmission, the transmission data (14) in frame units is stored in the memory (1), and the DMA control unit (10) is stored in the memory (1). The transmission data in frame units is taken out by the DMA control and transferred to the transmission / reception unit (3).
The transmission data in frame units transferred from the A control unit (10) is output to another data transmission control device, and the DMA control unit
(10) detects the end of the transmission data to end the DMA control, and in reception, the DMA control start / end control unit (13) is based on the control signal detected by the detection unit (12), and the transmission / reception unit (3) ) Starts the DMA control of the received data, and the DMA control unit (10) stores the received data in the frame unit by the DMA control.
The DMA control start / end control unit (13) stores the data in the (1)
A data transmission control device characterized by terminating DMA control of a control unit (10). 2. The data transmission control device according to claim 1, wherein the detection unit (12) detects the start and end of communication by recognizing a carrier signal. 3. The data transmission control device according to claim 1, wherein the detection unit (12) detects the start and end of communication by recognizing a signal of the I line. 4. A data transmission control device characterized in that the start of communication is detected by the detection unit (12) by recognizing a synchronization character or a synchronization pattern peculiar to a protocol included in a transmission frame.