JPH01103043A - Multiplex transmission equipment - Google Patents

Abstract

PURPOSE:To arrange a multiplex unit efficiently by using a partial period in a prescribed period as a communication time for synchronizing time division multiplex communication and applying asynchronizing time division multiplex communication in the remaining period. CONSTITUTION:A contention system transmission/reception section 10 and a time slot system transmission/reception section 11 are connected respectively to a transmission line 5 so as to transmit/receive a signal from/to the transmission/reception sections 10, 11. Then the partial period in a prescribed period is used for communication time for the synchronizing time division multiplex communication of the time slot system and the synchronizing time division multiplex communication in the transmission/reception section 11 is applied in the partial period. The contention system asynchronizing time division multiplex communication is applied with the transmission/reception section 10 in the remaining period in the prescribed time period.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a multiplex transmission device.

The multiplex transmission device according to the present invention can be used for signal transmission within a city, such as in a car.

[Conventional technology]

In recent years, electronic control of automobiles has progressed, and in such automobiles, it is necessary to transmit signals between various locations within the vehicle for various controls. The amount of such transmission signals tends to increase with the advancement of electronic control, and therefore the number of signal lines for signal transmission also tends to increase.

In response to this trend, it has been proposed to use multiplex communication technology in a signal transmission system in a vehicle as a means of reducing the number of signal lines and transmitting a large amount of data. This system installs multiplex units that perform time-division multiplex communication as terminals at locations in the vehicle where signal transmission is required, and connects the multiplex units with a single common transmission path to reduce the number of signal lines required. This is a significant reduction.

In such a multiplex transmission device, a method of communicating using synchronous time division multiplexing such as a time slot method, or a method of communicating using an asynchronous time-minute sub-length method such as a contention method has been proposed.

The time slot method performs signal transmission by assigning fixed time slots to each type of signal, and has the advantage of being relatively easy to control. , it takes time for the transmission and the response speed becomes slow.

The contention method prioritizes multiple signals, and when a signal transmission request occurs, the signal with the highest priority is transmitted block by block. Signals can be transmitted within a short time and the response speed is fast. . On the other hand, as the number of types of signals to be transmitted increases, control such as determining their priority becomes complicated. The cost of the equipment will also be high.

[Problem that the invention seeks to solve]

In conventional multiplex transmission equipment, all multiplex units within the equipment use the same communication method (e.g., time slot method or contention method), and there is no single device that uses two or more communication methods together. .

For this reason, for example, when a contention type multiplex transmission device is used for signal transmission inside a car.

This contention method is appropriate between units where a large amount of data needs to be transmitted with high response speed9, for example between a multiplex unit placed near the driver's seat and a multiplex unit placed on the rear seat side. However, on the other hand, if a very fast response speed is not required, such as a unit in a steering column that simply transmits 0N10FF signals for switches, it is not possible to use a contention type unit for such a unit. This is undesirable due to its high price, and when the number of switch signal types to be transmitted increases due to the addition of grade amplifiers or variations, the contention method makes control complicated, so it is easy to deal with these situations. I don't get it.

Therefore, an object of the present invention is to enable communication units with nine different communication types to be placed together in the same system, thereby efficiently arranging each communication unit in the most appropriate manner according to the characteristics of the installation location. The object of the present invention is to provide a multiplex transmission device that can perform multiple transmissions.

[Means for solving problems]

In order to achieve the above object, a multiplex transmission device according to the present invention includes a plurality of first communication units that perform communication using synchronous time division multiplexing, and a plurality of second communication units that perform communication using asynchronous time division multiplexing. and a common transmission path that interconnects these first and second communication units, and communication is performed between the second communication units by asynchronous time division multiplexing, and communication is performed between the first communication units at a constant period. It is configured such that communication is performed by synchronous time division multiplexing using only a predetermined partial section within.

[Effect]

A partial period in a fixed period is used as a communication time for synchronous time division multiplex communication such as a time slot method, and synchronous time division multiplex communication between the first communication units is performed during this partial period. During the remaining period of the fixed period, asynchronous time division multiplex communication using a contention method is performed between the second communication units, and communication between the first communication units is started during communication between the second communication units. When the time has come, it is also possible to give priority to the communication between the second communication units by canceling the communication between the first communication units in that period.

[Example] The present invention will be described in detail below with reference to one drawing. FIG. 1 is a block diagram showing a multiplex transmission apparatus as an embodiment of the present invention. In this embodiment, the multiplex transmission device of the present invention is used for signal transmission within an automobile.

In Figure 1, 1 is a master multiplex unit located in the dash panel near the driver's seat where the branching parts of the harness are concentrated, and has the function of performing multiplex communication by switching between the contention method and the time slot method. Equipped with.

Numerals 2 and 3 are multiplex units disposed on the passenger seat side and rear side, respectively, and have a function of performing multiplex communication using a contention method. Reference numeral 4 denotes a slave multiplex unit disposed in the steering column portion, which has a function of performing multiplex communication using a time slot method.

These multiplex units 1 to 4 are interconnected by a common transmission line 5 using a bus system.

Various switches, sensors, electronic devices, electrical loads, etc. in the vicinity of the master multiplex unit 1 and multiplex units 2 and 3 are respectively connected, and the multiplex units 1, 2 and 3 respectively connect these switches, It exchanges switch signals, drive signals, etc. with sensors, electronic devices, and electrical loads. These multiplex units 1, 2, and 3 mutually perform multiplex communication using a contention method, and are capable of transmitting and receiving a large amount of data that changes from time to time, such as image processing data, at high speed.

The slave multiplex unit 4 is a multiplex unit dedicated to transmission that receives 0N10FF signals from various switches near the steering wheel and sends them to the transmission line 5 in a time slot manner. Since these switch signals have little change over time and are small in amount, a low transmission speed is sufficient.

The block configuration of the master multiplex unit 1 is shown in FIG. As shown in the figure, a contention type transmitter/receiver 10
and a time slot type transmitter/receiver II are connected to the transmission line 5, respectively.
It is possible to send and receive signals from both. The transmitting/receiving units 10.11 are also respectively connected to the basic control logic unit 12.

The basic control logic unit 1 transmits transmission data to the transmission path 5.
2, and provides the received data received from the transmission path 5 to the basic control logic section 12. Basic control logic section 1
2 is a unit that processes data received from other units and creates data to be sent to other units.

The configuration is such that a signal indicating that transmission is in progress is inputted to the time slot type transmitting/receiving unit 11 from the Continuing Silang type transmitting/receiving unit 10.

The detailed configuration of the transmitter of the contention type transmitter/receiver IO is shown in FIG. Note that the transmitter in multiplex unit 2.3 also has a similar configuration.

In FIG. 3, the transmission messages received from the basic control logic section 12 are set in bit parallel in the shift register 100, and the set data is changed to the transmission clock CL by receiving the start signal S R (C).
The signals are sequentially sent to the transmission line 5 via the driver transistor 101 at the shift timing (C). The transmission line 5 becomes "dosinant" when the driver transistor 101 is turned on and becomes the ground level.
state (low level state).

Since the driver transistor 101 is turned off, “p”
ass jve” state (high level state).

The output signal of the shift register 100 and the output signal of the driver transistor 101 (i.e., the transmission signal on the transmission line 5)
are input to the AND gate 104 via inverters 102 and 103, and when the AND conditions of these signals are satisfied, the AND gate 104 sends a stop signal 5P(C) to the shift register 100, and the output from the shift register 100 is Data transmission is now stopped.

The output signal of impark 103 is also provided to counter 105 as counter reset signal R3.

The counter 105 is a 2-bit counter that counts the sending clock CL (C), and when it counts two sending clocks CL (C1) without being reset by the reset signal R3 from the inverter 103, an overflow signal CY is sent to the AND gate 106. Send.

The AND gate 106 receives the message set signal MS from the shift register 100, the overflow signal CY from the counter 105, and the output signal of the inverter 103 via the inverter 107, and when these AND conditions are satisfied, A start signal 5R(C) is sent to the shift register 100 to start data sending.

The detailed block configuration of the time slot type slave multiplexing unit 4 is shown in FIG. 4. As shown in FIG. Input and set. This set data is sent to the clock CL via the driver transistor 41.
It is sent to the transmission line 5 at the shift timing (S).

Data is sent from the shift register 40 using a start signal S.
R+3). Start signal S R
(3) is generated periodically by a timer at a constant period T (st). The output signal of the shift register 40 and the transmission signal on the transmission line 5 are each transferred to an inverter 42.
．． 43 to an AND gate 44, and when the AND condition is met, the AND gate 44 sends a stop signal S P 13) to the shift register 40 to stop sending out data from the shift register 40. In addition,
The transmitting circuit of the time slot type transmitting/receiving section 11 of the master multiplexing unit 1 also has a configuration similar to that of the circuit shown in FIG.

The operation of the above-described embodiment apparatus will be explained below with reference to FIGS. 5 to 7. First, the operation of the apparatus of this embodiment will be schematically explained. FIG. 5 is a time chart showing the usage status of the transmission line 5, as shown in FIG.

On the transmission path 5, a time slot transmission frame with a constant time slot time T (ft) is repeated every constant period T (st), and between time slot multiplex units, this time slot time T (ft) ) to perform time slot multiplex communication. At times other than the time slot time T (ft), 4-mslot multiplex communication is not performed, and continuous multiplex communication is performed exclusively between contention multiplex units. In this embodiment, the ratio of the fixed period T (st) and the time slot time T (ft) is as follows.

It is set so that T(ft)/T(st)<1/10.

Figure 6 is a diagram showing in detail the bit waveform of a time slot type transmission frame.As shown in the figure, one transmission frame consists of one start bit, eight data bits, and one stop bit. The time length of one bit of the slot is T (bt), and the NRZ modulation method is used as the signal modulation method.

FIG. 7 is a diagram showing bit waveforms when contention-based multiplex communication is performed. In this continuum system, a pulse width variable m (PWM) method is used as a modulation method, and the time length of one bit of a time slot in the continuum system is T (bc). The ratio to the time length T (bs) is.

T (bt) > 57 (be) It is set so that

As mentioned above, time slot data transmission is periodically performed between the time slot multiplexing unit 4 and the transmitting/receiving section 11 using the time slot time T (ft) in one cycle, and the time T (ft) is 1 hour. ft) at other times, Contincillin system multiple unit) 2.3. Transmitter/receiver lO
Continuous data transmission is performed asynchronously between the two. In this case, transmission using the Conchinciling method is given priority over transmission using the Time slot method, and if the transmission timing for the Time slot method comes while transmitting the Conchin Shirin method, the transmission using the Time slot method will be performed for that time. will be canceled. Even if this is done, there is no practical problem since data transmitted and received using the time slot method generally has little change over time.

The data transmission operation in the transmitting section of the Continuing System is shown in FIG.
The operation of the transmitter 0 will be explained below with reference to the operation of the transmitter. When transmission message data is created by the basic control logic section 12 and set in the shift register 100 of the transmission/reception section 10, data transmission based on contention is started. This data transmission is performed when a transmission message is set in the shift register 100 and the transmission path 5 is set to "passive".
e” state is detected for 27 (bc).

This transmission timing is determined by the counter 105. Anodogate 106. This is performed by a circuit consisting of an inverter 107. That is, the counter 105 sequentially counts the transmission clock CL (C1) with a period T (bc) and outputs the overflow signal CY when the count value reaches 2, but when the transmission line 5 is "dominant", the inverter 103 is output. The counter 105 receives the reset signal R3 and resets the count value. Therefore, while the continuum data from other multiplex units is being sent on the transmission line 5, the overflow signal CY is not output from the counter 105. , if the transmission line 5 is "passive" for 27 (bc) or more because the transmission line 5 is in an empty state, the counter 105 continues to count the transmission clock CL (C1) without being reset and overflows, and generates an overflow signal CY. Output.

The AND gate 106 detects that the data is set in the shift register 100 by the message set signal MS, and the output signal of the inverter 107 causes the transmission line 5 to be "
"passive" can be detected.

The transmission timing is detected by receiving the overflow' signal CY from the counter 105.

A start signal S R (C) is sent to the shift register 100. As a result, the shift register 100 is activated and sends the set data to the transmission line 5 via the driver transistor 101.

A circuit consisting of inverters 102, 103, and an AND gate 104 is used to store data when the transmission path 5 is already being used for transmission by another unit, or when a collision occurs due to simultaneous transmission with another unit with a high priority. This is for waiting for transmission.

In other words, the output signal is not being sent from the shift register 100! 3 (i.e. before data transmission).

Transmission line 5 becomes “dos+1na” due to transmission from other units.
nt'', a stop signal SP (C1) is output from the AND gate 104 to the shift register 100, so that even if data has been set in the shift register 100, data transmission from the shift register 100 is put on hold.

Furthermore, compared to the transmission signal of a unit with a low priority, the transmission signal of a unit with a high priority is set so that the period of "dominat" is longer than the period of "passive". Therefore, if it is detected that the transmission line 5 is "do+5inant" when transmitting "passive", the message transmission is temporarily interrupted, and the transmission line 5 is set to "do+5inant" again.
By waiting for the message to become "passive" and retransmitting it, a unit with a higher priority can preferentially start transmission when transmitting simultaneously between units.

The time slot type data transmission operation by the time slot type slave multiplexing unit 4 will be explained below with reference to FIG. 0N10FF signals from various switches are set as bit data in the shift register 4°, and by receiving a start signal SR+3) from a timer circuit at a constant period T(st), the set data is transferred through a driver transistor 41. It is sent to transmission line 5. In this case, if the transmission line 5 is already being used by another contention-based multiplex unit 2.3,
Before the set data is sent from the shift register 40, "do 1 nant" on the transmission line 5 is detected via the inverter 43, and the AND gate 44 sends a stop signal sp<=pc to the shift register 40 for that time. Stop data transmission. This gives contention-based data transmission priority over time slot-based data transmission.

Various modifications are made to reboiling in the practice of this invention. For example, in the above embodiment, a time slot type slave multiplex unit dedicated to transmission is shown, but the unit is not limited to this, and may be installed in the engine room to drive various electrical loads according to commands from a master multiplex unit. It may also be a reception-only time slot multiplex unit. Further, in the above embodiment, the multiplex transmission device of the present invention was applied to a signal transmission system in a car, but the invention is not limited to this.
The present invention can be applied to all signal transmission systems that transmit signals by synchronous time division multiplexing and asynchronous time division multiplexing.

〔Effect of the invention〕

According to the present invention, within one signal transmission device, transmission signals are stratified into those of a synchronous time division multiplexing method such as a time slot method and those of an asynchronous time division multiplexing method such as a contention method. Since the multiplex unit to be installed can adopt the communication method most suitable for the location where the multiplex unit is installed, efficient placement of the multiplex unit is possible.

This also helps reduce the cost of the device.

Furthermore, since it is relatively easy to increase the number of time slot multiplex communication units,9 when the multiplex transmission device of the present invention is used in, for example, an automobile signal transmission system,
Even if the number of signals to be transmitted increases due to upgrading or adding variations, it can be easily handled by adding a time slot multiplexing unit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a multiplex transmission device as an embodiment of the present invention, FIG. 2 is a block diagram showing the block configuration of the master multiplex unit in FIG. 1, and FIG. 3 is a contention system in FIG. 2. FIG. 4 is a block diagram showing the detailed configuration of the transmitting section of the transmitting section IO, FIG. 4 is a block diagram showing the detailed configuration of the transmitting section of the slave multiplex unit, FIG. 5 is a time chart showing the usage status of the transmission path, and FIG. Figures (al is a diagram showing the transmission frame of the time slot method, in Figure 6) are tights, diagrams showing the bit waveform of the slot method, and Figure 7
The figure is a diagram showing a bit waveform of the contention method. 1-Contention method/time slot method master multiplex unit 2.3-Contention method multiplex unit 4-Time slot method multiplex unit 5-.-Transmission line 10-Contention method transmitting section 1t-Time slot method transmitting/receiving section 12. -Basic control logic section Fig. 2 Fig. 3 +07 Fig. 4 Fig. 5

Claims (4)

[Claims] (1) A plurality of first communication units that perform communication by synchronous time division multiplexing, a plurality of second communication units that perform communication by asynchronous time division multiplexing, and these first and second communication units are mutually coupled. and a common transmission path, wherein communication is performed between the second communication units by asynchronous time division multiplexing, and between the first communication units, synchronous time transmission is performed using only a predetermined partial interval in a fixed period. A multiplex transmission device configured to perform communication by division multiplexing. (2) Claim 1, in which a communication unit including both a first communication section and a second communication section is connected to a transmission path.
The multiplex transmission device described in . (3) Claim 1 or 2 is configured such that asynchronous time division multiplex communication between the second communication units is given priority over synchronous time division multiplex communication between the first communication units. The multiplex transmission device described in . (4) The synchronous time division multiplex communication is a time slot type time division multiplex communication, and the asynchronous time division multiplex communication is a contention type time division multiplex communication, according to any one of claims 1 to 3. multiplex transmission equipment.