JPH11308206A - Information transmission method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a receiver to surely recognize a pause of data in the case of sending the data to a high speed transmission line via a low speed transmission line. SOLUTION: Sensors 10a, 10b, 10c supply detecting signals to an IC 12. The IC 12 converts the transmission rate from low to high and supplies the data to a microcomputer 14. In the case of sending non-fixed data whose the value is not fixed, the sensors 10a, 10b, 10c send the data by adding a bid whose the value is inverted for the every data. The microcomputer 14 recognizes the pause of the data by detecting the inverted bit in the received data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information transmission method, and more particularly to data handling in a system for transmitting data to a high-speed transmission line via a low-speed transmission line.

[0002]

2. Description of the Related Art Conventionally, there has been known a method of transmitting information by converting clock-synchronous low-speed communication and clock-synchronous high-speed communication.

For example, Japanese Patent Application Laid-Open No. 8-307416 discloses a technique for converting an input signal into an intermediate speed using a synchronous conversion circuit.
No. 26 discloses a technique for realizing a digital line interface for synchronizing between a high-speed transmission line and a terminal with a transfer rate conversion circuit.

[0004]

On the other hand, it is conceivable to apply such a transfer rate conversion to a communication system of an automobile to transmit an ignition signal of an airbag or the like at a high speed. In this case, in order to simplify the wiring harness and the like, it is desirable to transmit signals other than the ignition signal of the airbag and the like by the same transmission system.

FIG. 5 shows a timing chart at the time of transmitting data transmitted from various sensors.
(A) is a timing chart in a low-speed transmission system (for example, 125 kbps) from a sensor to a speed conversion IC, and (B) is a high-speed transmission system (for example, 1 Mbps) from a speed conversion IC to a microcomputer (hereinafter, referred to as a microcomputer). 4) is a timing chart. In the low-speed transmission system, data A, B, and C are transmitted at time intervals T1, and in the high-speed transmission system, data is transmitted at time intervals T2 (T1> T2).

Here, in the case of fixed data whose value is fixed like an ignition signal of an airbag, even if the speed is converted from a low-speed transmission system to a high-speed transmission system, the microcomputer recognizes the data. However, in the case of non-fixed data whose values are not fixed, such as the sensor number, it is necessary to correctly recognize each of A, B, and C in the figure. The microcomputer must be able to correctly recognize the breaks. However, in the conventional method of simply converting data to be transmitted at the time interval T1 to T2, the microcomputer cannot detect a break in data, and as a result, cannot correctly recognize non-fixed data. Was. In other words, in the example of FIG. 5, the microcomputer transmits data A repeatedly from the sensor, or the sensor transmits data A, B, and C, but the data is simply transmitted as a result of the speed conversion. It is not possible to distinguish whether A is repeated, and non-fixed data cannot be recognized correctly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and an object of the present invention is to provide an information transmission method capable of correctly recognizing non-fixed data on the receiving side even when the transmission speed is converted from low to high. Is to provide.

[0008]

According to a first aspect of the present invention, there is provided an information transfer method for transmitting fixed data and non-fixed data to a high-speed transmission line via a low-speed transmission line. When transmitting non-fixed data, it is characterized in that a bit indicating a data break is added and transmitted.
By adding a bit indicating a data break, the receiving side of a microcomputer or the like detects this bit so that even if the same data is input several times, the data break is reliably detected and non-fixed data is recognized. be able to.

According to a second aspect of the present invention, in the first aspect, the bit indicating the data break is a bit whose value is inverted for each data. By using the inversion bit, it is possible to detect a break in data simply but reliably.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual diagram of a system according to this embodiment. Various sensors 10a, 10b, and 10c are provided, and a detection signal and its part number data are converted to a speed conversion IC1.
Feed to 2. The speed conversion IC 12 converts the data transmission speed and supplies it to the microcomputer 14. Sensor 10a,
Clock-synchronized low-speed communication (for example, 125 kbps) is performed between the ICs 10b and 10c and the IC 12, and clock-synchronized high-speed communication (for example, 1Mbp) is performed between the IC 12 and the microcomputer 14.
s). The operation of the speed conversion IC is well known in, for example, the above-described conventional technology, and converts the data time interval T1 in the low-speed communication into the data time interval T2 (T1> T).
2).

FIG. 2 shows an example of a circuit configuration when such a system is applied to an airbag system of a vehicle. Various airbag sensors 10 such as side left and front left are provided, and supply detection signals to the IC 12. The IC 12 is provided with a sensor communication device, and has a 1 Mbp
The data is supplied to the communication port of the microcomputer 14 by the high-speed communication of s. Note that such a circuit configuration is merely an example, and it goes without saying that the present invention can be applied to any circuit configuration using speed conversion.

In such a configuration, when fixed data such as an airbag ignition signal is supplied from the sensor 10 (or the sensors 10a, 10b, and 10c) to the IC 12,
The IC 12 supplies this data to the microcomputer 14 by high-speed communication (1 Mbps). The microcomputer 14 controls the ignition of the airbag based on the data. On the other hand, sensor 1
When non-fixed data such as part number data or waveform data (data of acceleration g at the time of collision) is supplied to the IC 12 from 0 (or the sensors 10a, 10b, and 10c), the IC 12 performs speed conversion in the same manner as the fixed data. It is supplied to the microcomputer 14. Therefore, if the non-fixed data is simply transmitted in the same manner as the fixed data, since the same data is input several times as described above, a break in the data cannot be detected, and the microcomputer 14 correctly recognizes the non-fixed data. Can not do it.

Therefore, in the present embodiment, when non-fixed data is transmitted from the sensor 10 (sensors 10a, 10b, and 10c) to the IC 12, a bit indicating a data break is added and transmitted. In the IC 12, the data to which the bit indicating the break is added is speed-converted in the same manner as in the related art, and is supplied to the microcomputer 14. In the microcomputer 14, data can be separated by the value of a bit indicating a break included in the data, and non-fixed data can be correctly recognized.

FIG. 3 shows a timing chart when data is transmitted according to the present embodiment. (A) is a low-speed transmission system (for example, 125 kb) from the sensor to the speed conversion IC.
(B) is a timing chart in a high-speed transmission system (for example, 1 Mbps) from a speed conversion IC to a microcomputer (hereinafter referred to as a microcomputer). As before, in the low-speed transmission system, data A, B, and C are transmitted at time intervals T1,
In the high-speed transmission system, data is transmitted at time intervals T2 (T1> T2), but non-fixed data transmitted from the sensor is added with a bit 100 indicating a data break.
This bit is a bit whose value is inverted for each data, and has a value of “0” for data A, “1” for data B, and “0” for data C as shown in the figure. Then, IC
In the data supplied from 12 to the microcomputer 14,
In the data A, the bit values are all “0”, in the data B, all the bit values are “1”, and in the data C, all the bit values are “0”. By determining whether or not the same data is input several times, even if the same data is input several times, it is possible to reliably detect a break in the data and easily and reliably recognize the non-fixed data.

The inverted bit 1 indicating a data break
00 can be assigned to the seventh bit when each data (data A is illustrated in the figure) is transmitted in one byte as shown in FIG. 4, for example. Of course, the position of the inverted bit can be appropriately determined according to the system to be used or the type of data to be transmitted.

[0017]

As described above, according to the present invention,
Even when the transmission speed is converted from a low speed to a high speed, fixed data and non-fixed data can be correctly recognized on the receiving side.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a system according to an embodiment of the present invention.

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

FIG. 3 is a data transmission timing chart according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing inverted bit positions according to the embodiment of the present invention.

FIG. 5 is a conventional data transmission timing chart.

[Explanation of symbols]

10 sensors, 12 ICs, 14 microcomputers, 100
Inversion bit (bit indicating data break).

Claims (2)

[Claims] 1. An information transfer method for transmitting fixed data and non-fixed data to a high-speed transmission path via a low-speed transmission path, wherein a bit indicating a data break is added when transmitting the non-fixed data. An information transmission method characterized in that the information is transmitted by transmitting. 2. The information transmission method according to claim 1, wherein the bit indicating the data break is a bit whose value is inverted for each data.