JPS6251331A - On-vehicle electronic control equipment - Google Patents

Abstract

PURPOSE:To attain transmission/reception of a data between plural microprocessors inexpensively with a simple structure by connecting the plural microprocessors on one signal line in two-way so as to transmit/receive a signal between the microprocessors and providing a pause period of data transmission so as to synchronize the signal transmission/reception. CONSTITUTION:A signal line 20 connects electronic control equipments 10-13 in two-way via a serial transmission means provided to each microprocessor. An input terminal R and an output terminal T of the serial transmission means are connected respectively to the signal line 20 via transistors (TRs) 34 and 33. As to the data transmission, a desired data is written by a program into a transmission register provided in the inside of a processor 30, the data is outputted at each bit from an output terminal T in time series by the hardware processing in the processor 30 afterward, and as to the reception, when a data is fed at each bit in time series externally (from the signal line 20 in this case), the data is stored in a reception register in the inside of the processor sequentially.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention particularly relates to an on-vehicle electronic control device that controls an internal combustion engine, transmission, etc. of an automobile.

[Conventional technology]

With the recent development of microprocessor technology, this microprocessor is now used in automobiles, for example, to control internal combustion engines, control transmissions, and even display instrument panels. It has become common for devices to be equipped with microprocessors. Conventionally, these multiple microprocessors were configured to function independently without being related to each other, that is, without exchanging data with each other. From this point of view, there is a demand for data to be exchanged between these multiple microgloss setters and to be combined with each other.
, nine such devices have been proposed. For example, Japanese Patent Application Laid-Open No. 57-155603 proposes a device consisting of a plurality of electronic control units each consisting of one microprocessor and an input/output circuit, and one main microprocessor that controls them. In addition, various methods have been proposed for connecting multiple microprocessors in this way; for example, in Automation Vol. method is introduced.

[Problem that the invention seeks to solve]

Incidentally, in automobiles, particularly passenger cars, the price of the electronic control device mounted thereon must be extremely low compared to that in other industrial fields. Therefore, if a general method such as the above-mentioned system path connection is used, the device would be extremely expensive for use in an automobile, and it would be impossible to install it in an automobile due to the cost.

Furthermore, as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 57-155603, when a new main processor is used to control a plurality of processors, there is a problem in that the price increases accordingly. Furthermore, conventional individual automotive microprocessors are often used near the limits of their processing power, and thus multiple microprocessors! There are many practical problems in imposing a large number of new processes on the processor for exchanging data between the processors.

The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to obtain an on-vehicle electronic control device that can connect a plurality of microprocessors at low cost and in a simple manner.

[Means for solving problems]

The in-vehicle electronic control device according to the present invention bidirectionally connects a plurality of conventional in-vehicle microprocessors to a single signal line via serial transmission means provided therein, and performs control over this signal line. In addition to exchanging data between each microprocessor, a predetermined data transfer pause period is provided to synchronize data exchange between each microprocessor.

[Effect]

In this invention, since multiple microprocessors are combined using the serial transmission means provided in the microprocessors, the addition of hardware that occurs when combining them is minimized, and each microprocessor Since the data transfer is synchronized during the data transfer pause period, the addition of necessary processing programs to the software can be minimized.

〔Example〕

The following is an in-vehicle electronic control according to an embodiment of the present invention.

The apparatus will be described with reference to the figures.

FIG. 1 is a block diagram showing the configuration, and this embodiment shows the case where the number of microprocessors is four. In the figure, IO to 13 correspond to conventional electronic control units, and their configuration is similar to that of the second
It is as shown in the figure. Further, 20 is a signal line that bidirectionally connects these electronic control devices (hereinafter simply referred to as devices) 10 to 13 to each other via a serial transmission means provided in the microprocessor.

FIG. 2 is a block diagram showing the configuration of each of the above devices 10-13. In the figure, 30 is a microprocessor equipped with serial transmission means, the output terminal T is its data transmission port, and the input terminal R is its data reception port. 31 is an input interface circuit that receives signals from a sensor that detects, for example, the throttle opening of the automobile, and 32 is an output interface circuit that drives each actuator of the automobile. te, the input terminal R and the output terminal T of the serial transmission means are connected to the signal line 20 via transistors 34 and 33, respectively.

The specific method of the above serial transmission is as follows □
It's becoming a sea urchin. In other words, when transmitting data, the program writes the desired data to the transmit register (transmit data register) inside the grosser. The ' data is output from the output terminal T in time series for each pit, and for reception it is sent to the external (in this case, the
・When data is applied time-sequentially for each pit from line 20), it is sequentially stored in a reception register (receive data register) inside the processor, and a predetermined number of bits (for example, 8 pits in an 8-pit processor) are received. Once completed, a predetermined flag inside the processor (
Receive register full flag) is set.

Next, the operation of the in-vehicle electronic control device configured as described above will be explained using the timing chart shown in FIG. This FIG. 3 shows the state of data transmission on the signal line 20, and after a predetermined data transfer suspension period indicated by TO in the figure, the device lO transmits a predetermined number of data transfers (in the figure, data (0, 1, 2, 3)
is output through the transistor 33 to the output terminal T. When the transfer of this predetermined number of data is completed, the device 1
Similarly, device 12 and device 13 transfer data onto the signal line 20 in the same manner. The data on this signal line 20 is transferred to the transistor 34.
The data is read from the input terminal R of each processor 30 via the input terminal R of each processor 30. Each processor 30 constantly monitors the interval of this data transfer using its own timer function (timekeeping function), and the interval is the period during which data is continuously transferred, indicated by T1 in the figure. If the interval is longer than a predetermined period, it is determined that this is the data transfer suspension period TO,
The first data transferred next is determined to be the first data 0 from the device 10, and the number of data sequentially transferred to the signal line 20 is counted from then on, and data is transferred according to the count value. □Give and receive. For example, in the case of the device 11, the data transfer suspension period TO is
After detecting , the number of data is counted, and if the number is 4 or less, it is determined that the data is transferred from the device 10, and after counting these 4 data, the device 11 transfers its own predetermined data. (0 to 4) sequentially on the line 2
Transfer on 0. Since the number of data is counted in this way, all the devices 10 to 13 can know which device and what number of data the data currently on the line 20 is. If the data is necessary for the device itself, processing such as storing the data in the device's own memory can be performed. When the data transfer from all the devices 10 to 13 is completed as described above, all of these devices 10 to 13 stop their data transfer operations for the predetermined period TO, and thereafter perform the above series of data exchange processing in a cyclical manner. I will go to Note that the data transfer suspension period TO is set longer than the data transfer interval T1.

Next, an example of the program processing procedure of each microprocessor 30 will be explained according to the flowchart shown in FIG. In this example, an interrupt is generated each time data is received from input terminal R of the processor 30 and the flag (receive register full flag) indicating completion of reception is set. In the main processing routine shown in the figure, after the counter for counting the number of data items is cleared to zero, conventional control processing, such as control processing of the idle speed of the engine, etc., is performed. During this process, when data is received from the signal line 20, an interrupt occurs as described above, and the interrupt processing routine shown in the figure is executed. In this interrupt processing routine, first, a data transfer interval is determined. This determination may be made, for example, by referring to a timer register (timekeeping register) provided within the microprocessor 30.
I can do it. As a result of this determination, if the transfer interval is longer than the data transfer interval Tl by υ, the counter is cleared to zero.
If not, it is incremented (l is added). That is, the counter is cleared to zero during the data transfer suspension period TO, and thereafter is incremented by one every time one piece of data is received.

Next, if the friend data received according to the count value of this counter is necessary for the device itself, such as engine rotation speed information, it is sent to the receive device.

– Read from the data register and store it in memory.
Note that the number of pieces of data sent from which device and the type of data is determined in advance between the devices.
The data 2 is programmed in advance as throttle opening information. Next, if the next data is to be transferred by the device itself according to the count value of the counter, predetermined data is transferred onto the line 20 as described above. For example, in the device 11, after receiving the fourth data 3 from the device IO,
Next, the first data is transferred by writing it to the transmit data register.

After executing the above processing, the interrupt processing ends. Note that, unlike the other devices 11, 12, and 13, the device 10 needs to transfer the first data after the data transfer suspension period TO, and the processing routine for this purpose is the same as each processing routine shown in FIG. added to others. That is, in the device 10,
A processing program is added that transfers the first data O after a predetermined time TO after receiving the last data 5 from the device 13.

〔Effect of the invention〕

As described above, according to the present invention, a plurality of microprocessors are bidirectionally connected to one signal line via the serial transmission means provided therein, and signals are exchanged between each microprocessor. The structure is configured so that the signal transmission and reception is synchronized by providing a pause period for data transfer, so the addition of hardware and software that is required when connecting each microprocessor is extremely small, and the structure is simple and inexpensive. This has the effect of providing an on-vehicle electronic control device that can exchange data between a plurality of microprocessors.

[Brief explanation of drawings]

FIG. 1 shows the configuration of an in-vehicle electronic control device according to an embodiment of the present invention! Figure 4, Figure 2 is a block circuit diagram showing the configuration of the electronic control device in the vehicle-mounted electronic control device;
FIG. 3 is a timing chart showing the state of data transmission in the in-vehicle electronic control unit, and FIG. 4 is a flowchart showing the procedure of data transmission processing. 10.11,12,13...Electronic control device, 20...
・Signal line, 30...Microprocessor, 31・
...Input interface circuit, 32...Output interface circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] An on-vehicle electronic device comprising a serial transmission means, a plurality of pre-numbered microprocessors, and the plurality of microprocessors bidirectionally connected to one signal line via the serial transmission means. In the control device, the plurality of microprocessors sequentially transfer a predetermined number of data onto the signal line in accordance with the respective numbers after a predetermined data transfer suspension period, and transfer the data on the signal line. The number of pieces of data from the pause period is counted, and predetermined data determined in advance according to the above number is taken from the signal line, and thereafter, the data transfer operation that follows these series of data transfer pauses is performed cyclically. An in-vehicle electronic control device characterized by: