JPH0568071A - Data transmission system - Google Patents

Abstract

PURPOSE:To obtain the serial data transmission system capable of asynchronously transmitting a reset request to a reception side even when a transmission side is in data transfer state. CONSTITUTION:A reset control bit for reset is provided in addition to a data bit string in the unit of parallel data and the data are transferred in the unit being the sum of a data bit and a bit for the reset. A reset code analysis section 7 sets asynchronously a reset control bit and a reset code analysis section 8 analyzes asynchronously it. Thus, a reset request is transmitted to a reception side in a prescribed short time at all times independently of the presence of data transfer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission system, for example, to a receiving side reset system in a serial data transmission system.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a system configuration in a conventional serial data transmission system. In the figure, 1 is a data packet generation unit for packetizing transfer data, 2 is a transmission line encoding unit for performing transmission line encoding of the packetized data for serial conversion, and 3 is a transmission driver for sending serial data to the transmission line. Section 4, a receiver section for receiving transmission path data, 5 decoding the received data,
A decoding unit 6 which performs parallel conversion for passing to the system side, and a data extraction unit 6 which extracts data from the received packet.

Next, the operation will be described. The data packet generation unit 1 generates n bytes of transmission data as one packet data. The packet generated here is sent to the transmission path coding unit 2 as one transfer unit. The packetized data is channel-coded into a serial data string by parallel-to-serial conversion. The serial data string is output to the transmission line through the transmission driver unit 3. The serial data string input to the receiving unit via the transmission path is received by the receiver unit 4 and serial-parallel conversion and decoding are performed by the decoding unit 5. The decrypted data is depacketed by the data extraction unit 6 and passed to the lower system as received data.

[0004]

Since the conventional serial data transmission system is configured as described above, even if the transmitting side wants to asynchronously issue the reset request to the receiving side during the data transfer, the present serial data transmission system is currently used. Had to wait for the end of the packet data transfer, and it wasted time before the reset request was transmitted to the receiving side. This is because the dead time becomes longer as the remaining packet amount to be transferred increases.

The present invention has been made in order to solve the above-mentioned problems, and a reset request can be transmitted from a transmitting side to a receiving side asynchronously regardless of whether packet data is being transferred or not. An object of the present invention is to obtain a data transmission method that can asynchronously send a control request to the receiving side regardless of whether or not actual data transfer is performed as described above, not limited to the reset request.

[0006]

A data transmission system according to the present invention is a data transmission system in which data is serially transferred in a synchronous system. For example, a control bit for resetting is provided in addition to a data bit string, and a bit of data is provided. A reset request to the receiving side is performed asynchronously with the data transfer by performing a transfer in a unit in which the reset bit and the reset bit are combined.
It has the following transmitting side device and receiving side device. (A) A transfer unit having a data area for storing data information and a request area for storing a control request to the receiving side device such as a reset request is transmitted to the receiving side device by a synchronous serial transfer method and received. A transmission side device for asynchronously storing a control request to the transmission side device in a request area, (b) a transmission side device which receives a transfer unit from the transmission side device by a synchronous serial transfer method and is stored in the request area The receiving side device that analyzes control requests from the server asynchronously.

[0007]

In the present invention, since the request area is provided in advance in the transfer unit to be transmitted / received, even if the transfer unit is transmitted / received in the synchronous system, the control of the reset request etc. from the transmission side device to the reception side device When a request occurs, the control request can be asynchronously set in the request area of the transfer unit that is about to be transmitted next.

[0008]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a data packet generation unit for packetizing transfer data, 2 is a transmission line encoding unit that performs transmission line encoding of the packetized data and performs serial conversion, and 3 is transmission for transmitting serial data to a transmission line. A driver unit 4, a receiver unit for receiving transmission path data, 5 a decoding unit for decoding the received data and performing parallel conversion for passing to the system side, 6 a data extraction unit for extracting the data from the received packet, Reference numeral 7 is a reset code generation unit that generates a reset code to be added for each transfer unit of data to be transferred, and 8 is a reset code analysis unit that analyzes the reset code extracted from the received data string and determines whether there is a reset request. is there. Above 1,
2, 3, and 7 constitute a transmission side device (hereinafter, also abbreviated as a transmission side), and the above 4, 5, 6, and 8 constitute a reception side device (hereinafter, abbreviated as a reception side). It is configured.

Next, the operation will be described. The normal transmission data transmission method and reception method are the same as the conventional methods. Here, the operation when the transmitting side wants to issue a reset request to the receiving side during data transfer will be described. FIG. 2 shows a data structure for implementing the present invention. Reference numeral 10 is one packet data transferred by one transfer start, and 20 is one parallel data unit, which is referred to as one transfer unit here. One bit of reset code is provided in addition to the transfer data. At the time of normal data transfer, the reset code is added to each transfer unit as a reset request absence state "0". When a reset request is issued, the reset code generation unit 7 of FIG. 1 adds the reset code as a reset request present and adds the reset code as a reset request presence state "1" for each transfer unit. On the reception side, the reset code analysis unit 8 checks the reset code every time the transfer data is received, and when the reset request presence state is detected, it is determined that there is a reset request from the transmission side, and it is predetermined by the reception side. Perform a reset operation.

Regarding the presence / absence of data transfer (presence / absence of data in the data area), even when actual data is set in the data area of the transmission / reception transfer unit,
Alternatively, it does not matter if it does not exist. In other words, since it is a synchronous method, even if a packet of only a frame with no data occurs and a so-called empty packet is transferred, it is possible to send a control request using the request area of that empty packet. Is.

As described above, according to this embodiment, the reset request from the transmitting side can be transmitted to the receiving side asynchronously regardless of the presence / absence of data transfer. It is possible to obtain a data transmission method that prevents a reset request transmission delay that occurs when data is being transmitted at the time of issue.

Example 2. In the above embodiment, the case of the reset request has been described, but the present invention is not limited to the reset request and may be a control request from the other transmitting side to the receiving side. When it is possible to transmit and receive a plurality of control requests, the request area requires a plurality of bits. For example, if the required area consists of 2 bits,
It is possible to send and receive up to three types of control requests.

Embodiment 3. Further, in the above embodiment, the case where the transfer unit is the packet format has been described, but other formats may be used as long as they are synchronous serial transfer.

As a technique related to the present invention, there is a technique disclosed in Japanese Patent Application Laid-Open No. 58-50848. This technique has two transmission lines and these two transmission lines are turned on. , OFF to control the connected terminals, which is different from the invention of this application.

Similarly, Japanese Utility Model Laid-Open No. 62-57843 discloses a technique of resetting a partner device by making the data length of a transfer unit longer than a normal length in a serial data transmission device. However, the invention according to this application is different in that the length of a transfer unit is always constant.

[0016]

As described above, according to the present invention, it is possible to obtain a data transmission system capable of asynchronously sending a control request to the receiving side regardless of the presence or absence of data transfer.

[Brief description of drawings]

FIG. 1 is a diagram showing a data transmission system of the present invention.

FIG. 2 is a diagram showing a data structure of the present invention.

FIG. 3 is a diagram showing a conventional data transmission method.

[Explanation of symbols]

 7 Reset code generator 8 Reset code analyzer

Claims (1)

[Claims] 1. A data transmission method having at least one of the following transmitting side device and receiving side device: (a) A data area for storing data information and a request for storing a control request to the receiving side device such as a reset request. And a transmission unit that transmits a transfer unit having an area in advance to the reception side device by a synchronous serial transfer method and asynchronously stores a control request to the reception side device in the request area, (b) From the transmission side device The receiving side device that receives the transfer unit of the above in the synchronous serial transfer method and asynchronously analyzes the control request from the transmitting side device stored in the request area.