JPS6022844A - Multiplex transmission system with priority - Google Patents

Abstract

PURPOSE:To improve throughput and response by corresponding the number of times of transmission to the responsiveness of information in a system transmitting cyclicly load information and sensor information through the use of time division multiplex. CONSTITUTION:A data D1 having a header h1 of (0, 0) thereby requesting the very fast responsiveness is stored in the 1st, 3rd and 5th bytes respectively, a data D2 having a header h2 of (0, 1) thereby requesting a comparatively fast responsiveness is stored respectively to the 2nd and 6th bytes, and data D3, D4 having header h3 of (1, 0) and (1, 1) respectively thereby not requesting the fast responsiveness are stored respectively to the 4th and 7th bytes in the Tn cycle of data transmission, and the data D1-D4 are transmitted in the time division system. Since the number of times of transmission of the data are made different in one cycle (3 times for the data D1, two times for the data D2 and one time for the data D3, D4) and the data D1, D2 requiring the high responsiveness are transmitted with the higher priority, the throughput and responsiveness are improved.

Description

[Detailed Description of the Invention] The present invention relates to a prioritized multiplex transmission system, and is intended to improve the responsiveness of the entire transmission system by shortening the transmission interval for data that requires a fast response speed. .

In the system inside a car, where there are many devices to be controlled (loads such as lamps) and information source devices (sensors) that provide the information necessary for controlling these devices, communication is necessary to simplify the connections between each device. Multiplex transmission via the control device takes place.

Here, a specific example of an automobile transmission system will be explained based on FIG. 1, which shows a part of the transmission system. There are various types of transmission systems such as tree, star, and loop, but the operation of each part is the same. As shown in Figure 1, communication control devices A and B are connected by a transmission path d, and the transmission side (
+ll is performed. Further, the communication control devices A and B have loads a-1, a-2, b-] connected to themselves.

Controls b-2 and sensors a-3, a-4, b-3, and b-4.

Transmission from communication control device A to communication control device B &:1:
, which is conventionally carried out based on a transmission format as shown in FIG. That is, focusing on the Tn cycle, data D1 is stored in the first byte, data D2 is stored in the second byte, data D is stored in the third byte, and data D4 is stored in the fourth byte. These data D, -D4
are transmitted in this order in a time-division manner. The first two bits of each data D, ~D4 are ro, oJ, ,
ro, xJ.

[, oJ, rt, xJ headers h, -h are placed, and the data contents of these headers h1 to h are identified.The data content itself is 6 following the headers h, -h4.
O stored in bit data content storage sections d and -d4
In this case, data contents of 6 bits are stored in each of the data contents storage parts d, ~d, and the data contents storage part d.
The data content of 2 bits is stored in d4, and the remaining 9 4 bits of the data content storage area d4 are vacant. Therefore, 20 bits worth of data content information is sent from communication control device A to communication control device B. In this case the header h,
Since -h4 is attached, the receiving side can accurately determine which data it is.

When transmitting each data D and -D4, a first start hit is attached to each data, and a parity pit and a stop pit are attached after each data, and the data is serially transmitted. - As an example, the format for transmitting data Ds is shown in FIG. Adopts Naba pulse width modulation, etc.

Furthermore, in other cycles Tn-x, Tn+x, etc., data D and -D4 are transmitted in a time-divided manner. The data D, . . . , D are sequentially transmitted cyclically as one set.

By the way, in the conventional transmission method as described above, each data D and -04 are distributed evenly during one cycle.
The throughput and responsiveness of the transmission system as a whole were poor.

Each data D, -D.

If there is a mixture of data that changes in seconds and needs to be transmitted in seconds, and data that changes in minutes and needs to be transmitted in minutes, then With data, new data cannot be transmitted until the next cycle and changes in data cannot be followed. Conversely, with minute data, data is transmitted every cycle and the same data is duplicated. It is unreasonable that there may be cases where the person is sent.

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, it is an object of the present invention to provide a prioritized multiplex transmission system that can improve throughput and responsiveness. The configuration of the present invention that achieves this objective is to transmit multiple types of data in a time-sharing manner, each having a header for identifying the data content at the beginning, and then transmit the data in the same manner after the cycle is completed. In a multiplex transmission system in which the next cycle continues sequentially, among the data transmitted in each cycle, the frequency of transmitting data that requires quick response is increased, and the frequency of transmitting data that does not require so much quick response is decreased. It is characterized by

Examples of the present invention will be described in detail below.

FIG. 4 shows a transmission format of an embodiment of the present invention. As shown in the figure, in the Tn cycle, data D2 is stored in the 1st, 3rd and 5th bytes, respectively, and data D2 is stored in the 2nd and 6th bytes. It is stored in the 4th hide of Dstt,
Data D4 is stored in the seventh byte, and each data DI"" D4 is transmitted in a time-sharing manner in the illustrated storage order. In other cycles Tn-1, Tn+, etc., data is stored and transmitted in the same manner as in the Tn cycle.

Of the above data D, ~D4, header h is l'-0, O
The data D1, which is J, is data for a horn switch or a turn switch, and extremely quick response is required. Further, the data D, in which the head h is lo, x, J, is the data of the headlamp switch, and requires relatively quick response. On the other hand, data D whose header h3 is rl, OJ,
is speedometer data, header hs is rl,
The data D4, which is IJ, is the data of the fuel gauge, and the data D3 and D4 do not require much prompt response.

In this way, in this embodiment, the data D is
, ~D4 are made to have different transmission frequencies.

That is, within a cycle, the transmission frequency of data D is 3
times, the transmission frequency of data D is twice, data Ds, D
The transmission frequency of 4 is once each. Therefore, in terms of responsiveness, data DI is fastest, data D2 is next fastest, and data D3 and D4 are slow. In this way, since the data D, , D, which require quick response are transmitted with high priority, the throughput and responsiveness of the entire transmission system are improved.

Next, FIG. 5 shows the circuit configuration of a transmission system that performs transmission using this method. As shown in the figure, the transmitting circuit 1 includes an 8-bit memory 1a, a parallel/serial converter 1b, a parity generator 1c, a write controller 1d, and an oscillator (OSC).
1 e. The input data is input as parallel information to the input boat selection circuit 2, a header corresponding to the data content is added by the header circuit 3, and then stored in the memo IJIQ.

Storage in the memo IJ 1a is controlled by the write controller 1d. The data stored in memory 1a is parallel/
The serial converter 1b converts the signal into serial information, and the parity generator 1c adds parity to the signal, which is then output. The output data is converted into optical information by an electrical/optical converter 4 and transmitted via a transmission line 5 formed of an optical fiber.

The data transmitted through the transmission line 5 is converted into electrical information (serial information) by an optical/electrical converter 6 and received by a receiving circuit 7. The receiving circuit 7 includes a memory 7a, a serial/parallel converter 7b, a checker 7c for checking parity and frame length, a read controller 7d, and an oscillator 7e.
It becomes. The data input to this receiving circuit 7 is converted into parallel information by a serial converter 7b and then stored in a memory 7a. The data stored in the memory 7a is read out under the control of the readout controller 7d, and is received by the output boat selection circuit 8. At this time, the header decoding circuit decodes the header of the data received by the output boat selection circuit 8 and identifies the data contents.

As specifically explained above in conjunction with the embodiments, according to the present invention, the frequency of data transmission is varied according to the promptness required for each data within each cycle, so the response speed is adjusted according to the priority of information. can be changed to improve throughput and responsiveness. Therefore, it is suitable for use as a transmission method in a multiplex transmission harness for an automobile, where the promptness required for each data is greatly different.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing a specific example of an automobile transmission system, and Figure 2 is a transmission format that explains the conventional transmission system.
Figures 1 and 3 are transmission format diagrams 6 and 6 showing the mode of transmitting each data, Figure 4 is a transmission format diagram for explaining the transmission method of the present invention, and Figure 5 is the method of the present invention. FIG. 2 is a circuit configuration diagram showing a transmission system that performs transmission. In the drawing, h, , h2. h8. h, is the header, D+,
D2, Ds, D4 are data, di * d2
r d3 ra is a data content storage unit, Tn-r,
Tn and Tn+x are each cycle. Patent applicant Sumitomo Electric Industries, Ltd. Representative Patent Attorney Shibu Mitsuishi (and 1 other person) 231

Claims (1)

[Claims] A multiplex transmission method in which multiple types of data, each with a header at the beginning that identifies the data content, is transmitted in a time-division manner - After a cycle is completed, the next cycle of transmitting the data in the same way continues one after the other. A prioritized multiplex transmission method characterized in that, among the data transmitted in each cycle, the frequency of transmitting data that requires quick response is increased, and the frequency of transmitting data that does not require so much quick response is decreased. .