JPH05252207A - Data transfer system - Google Patents

Abstract

PURPOSE:To allow a receiver side to identify an intended interruption of a sender side from a usual momentary error when the sender side desires intentionally the interruption of transmission during packet transfer. CONSTITUTION:An information flag (field 20) able to recognize an attribute of data is added to the data for each parallel/serial conversion unit per one time and the receiver side distinguishes valid data and interruption information depending on the information flag. Thus, the intentional interruption is surely sent from the sender side to the receiver side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet-type serial data transmission system, and more particularly to a data transfer system in the case where a transmission side intentionally cancels transfer during packet transfer.

[0002]

2. Description of the Related Art FIG. 4 shows, for example, JP-A-2-39902.
2 is an example of a system configuration showing interruption processing at the time of packet data transfer in the conventional data transfer method disclosed in Japanese Patent Publication No. In FIG. 4, 1 is a data processing circuit, 2 is an error detection code generation circuit, 3 is an exclusive OR gate (EO).
R), 4 is a selection circuit, 5 is an end code generation circuit, 6 and 7 are transmission line interfaces, 8 is an error detection circuit, 9 is an end code detection circuit, 10 is a line, and 11 is a terminal. FIG. 3 is a diagram showing an example of a data format in the conventional example. In FIG. 4, 40 is a field for transmitting data, 41 is a field for transmitting an end code, and 42 is a field for transmitting an error detection code. FIG. 3A shows a format for normal packet transfer. If the transmission is interrupted during the packet transfer, in the conventional example, as shown in FIG. 3B, the end code ED is put in the field 41 for transmission, and then the error detection code CHK is inverted in the field 42 ( Insert CHK *) and send.

Next, the operation of the conventional data transfer method will be described. The data processing circuit 1 receives the data sent from a host system (not shown) via the line 10. This data is output to the terminal 11 via the selection circuit 4 and the interface 6. The selection circuit 4 generates an error detection code corresponding to the data given to the error detection code generation circuit 2. The data processing circuit 1 sends out the data via the selection circuit 4 and outputs an end signal to the end code generation circuit 5 and the error detection code generation circuit 2. At this time,
In response to the end signal, the data processing circuit 1 outputs the end code and the error detection code to the selection circuit 4 and also outputs the selection switching signal to the selection circuit 4. Here, when it becomes necessary to stop data transmission to the data processing circuit 1 due to some factor, the data processing circuit 1 immediately outputs a transmission stop signal to the error detection code generation circuit 2 and the termination code generation circuit 5. At the same time, the transmission stop signal t is set to "1",
The error detection code CHK is inverted via the exclusive OR (E0R) gate 3, and after the aborted transmission data (field 40), the end code ED (field 41) and the inverted error code CHK * (field 42). Is output. The terminal 11 detects an abnormality in the data processing circuit 1 by detecting the end code ED and the inversion error code CHK *.
On the other hand, the reception signal of the terminal 11 is input to the data processing circuit 1 via the reception interface circuit 7, and
The signal from the transmission line interface circuit 7 is also input to the error detection circuit 8 and also to the end code detection circuit 9, and the end code ED is detected.

[0004]

As described above, according to the conventional data transfer method, when it is desired to immediately interrupt the data before the completion of the transmission of the transfer data, the data already transmitted (field 40) is The transmission end code ED (field 41) is sent, and the error detection code CHK (field 41) is inverted and output as CHK *. On the other hand, on the receiving side, the error detection code is abnormal.Therefore, on the receiving side, an instantaneous error on the transmission line, which is the original check function, may have occurred whether the error that occurred this time was intentionally interrupted by the transmitting side. There is a problem that it is impossible to separate it. Further, since the data processing circuit 1 has to perform the procedure of inverting and transmitting the transmission end code ED and the error detection code CHK, there is a problem that the processing circuit configuration becomes complicated.

The present invention has been made in order to solve the above problems, and when the transmitting side, which is also an advantage of the prior art, wants to interrupt the transmission, it can immediately notify the receiving side of the abnormality, and the transmitting side can It is an object of the present invention to provide a data transmission method that can clearly distinguish between intentional data transfer interruption and instantaneous error on the transmission path, and also that simplifies transmission means of transmission interruption and is simple and inexpensive as an apparatus.

[0006]

A data transmission system according to the present invention, as shown in FIG. 1, serially transfers a data string of one parallel / serial conversion unit for each transfer by a packet system and transmits the data. In the data transfer method in which when the transmission side interrupts transmission due to a transmission error or the like, in the data transfer system in which the interruption is transmitted to the reception side, a bit information flag (field 20) is added to each data string of one transfer unit, and the transmission side interrupts. In this case, a data transfer method characterized in that the bit information flag is set as interruption information and transmitted to the receiving side.

[0007]

The data transmission method according to the present invention has a bit information flag for distinguishing the information type of the data for each data transfer unit, and the receiving side recognizes the normal data transfer and the abnormal data transfer by recognizing the information flag. It makes it easy to distinguish.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a format of packet data of a data transfer system according to an embodiment of the present invention. Figure 1
In the figure, 20 is a field to which an information flag as a bit information flag is input, and 21 is a field of the selection circuit output data, and one parallel / serial conversion unit is one transfer unit. In this embodiment, a 2-bit information (00-11) flag is added to each transfer unit. According to the information flag of the field 20, each transfer unit has four pieces of idle information of "00", valid data of "01", error detection code of "10", and transfer interruption of "11".
Classified into types. 2 is a block diagram of a system configuration of a data transmission / reception unit using the data format of FIG. 1. In FIG. 1, 1 is a data processing circuit, 2 is an error detection code generation circuit, 4 is a selection circuit, and 5 is an information flag generation. Circuits, 6 and 7 are transmission line interfaces, 8 is an error detection circuit, 9 is an information flag recognition circuit, 10 is a line, and 11 is a terminal. The same parts as those in the conventional example (FIG. 4) are designated by the same reference numerals, and the following description will be omitted.

Next, the operation of this embodiment will be described. First, the data processing circuit 1 receives, via the line 10, data sent from a host system (not shown). The data processing circuit 1 specifies the idle information “00” to the information flag generating circuit 5 while there is no data to be sent to the transmission line interface. When the data processing circuit 1 transmits data from the host system, the data is output to the line 10 via the selection circuit 4, the transmission line interfaces 6 and 7, and the terminal 11, and at the same time, error detection is performed. Data is input to the code generation circuit 2. Also, in synchronization with the transmission of this data, the effective data "01" is sent from the information flag generation circuit 5, and the output data from the selection circuit 4 is added to generate packet data of one transfer unit. After the completion of the transmission of the packet data of one transfer unit, the data processing circuit 1 switches the selection circuit 4 to send the information data of the error detection code generation circuit 2 and at the same time.
An error detection code "10" is added as an information flag (field 20) of this information data. On the other hand, the information flag recognition circuit 9 on the receiving side checks the information type of each transfer unit that is always sent, and if the information flag of the field 20 is idle information "00", it is discarded.
If the valid data is “01”, the packet data is input to the data processing circuit 1. If the error detection code is "10", the error detection circuit 8 checks the validity of the packet data already received.

If the transmitting side wants to interrupt the data transfer for some reason during the packet data transfer, the data processing circuit 1 on the transmitting side instructs the information flag generating circuit 5 to transfer the information data of the transfer interruption "11". Should be set. on the other hand,
The information flag recognition circuit 9 on the receiving side recognizes the interruption of the transfer from the information flag, judges that the transmitting side has intentionally completed the transmission, and carries out the interruption process arranged by each host system.

[0011]

As described above, according to the present invention, when the transmitting side interrupts the transmission to the receiving side except for an abnormality such as a transmission error, the bit information flag for transmitting the interruption information is provided. There is an effect that the transmission interruption request from the side can be recognized immediately by the reception side, unlike the conventional case, by distinguishing from the instantaneous error. Further, since the circuit configuration is simple, there is also an effect that it is possible to configure a system that is cheaper and more compact than the conventional one.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of a system of a data transmitting / receiving unit using the data format of FIG.

FIG. 3 is a diagram showing a data format according to a conventional example.

FIG. 4 is a system configuration diagram of a data transmission / reception unit using the data format of FIG.

[Explanation of symbols]

 1 data processing circuit 2 error detection code generation circuit 4 selection circuit 5 information flag generation circuit 8 error detection circuit 9 information flag recognition circuit 20 field (information flag)

Claims (1)

[Claims] 1. A parallel / serial conversion unit data string is serially transferred by a packet method for each transfer, and when the transmission side interrupts the transmission due to a transfer error or the like, the interruption is notified to the receiving side. In the data transfer method, a bit information flag is added to each of the data strings of one transfer unit, and when the transmitting side suspends, the bit information flag is set as suspending information and transmitted to the receiving side. Transfer method.