JP3181330B2 - Multiplex transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex transmission apparatus in which a plurality of communication nodes are connected to a single transmission line and multiplex transmission of data is performed by frequency control or time division.

[0002]

2. Description of the Related Art In recent years, electronics in automobiles have been remarkably increased, and a large number of electrical components such as switches, sensors, and actuators have been provided, and the wiring harnesses connecting the electrical components have become seriously enlarged and complicated. It is becoming a problem, and in order to solve this problem,
As described in Japanese Patent No. 4658, a multiplex transmission system in which a transmission line is shared by a large number of electrical components is adopted, a communication node including various operation switches and display devices, an air conditioner,
A communication node of a control system such as an audio device, an engine control (EGI), a four-wheel steering control (4WS), and an antilock brake control (ABS) has a multiplex module, and is connected to a multiplex transmission path to perform multiplex communication. What constitutes a system is known.

In the above multiplex communication system, in order to prevent power consumption of the battery, when the ignition key is removed, each communication node is set to a sleep state, that is, a non-operation state, so that power is not supplied to the multiplex module which consumes a large amount of power. When the ignition key is inserted and turned on, a wake-up signal is issued by a multiplex communication signal via a multiplex transmission line to wake up or start each communication node, energize the multiplex module, and enter an operation standby state. However, in this multiplex communication system, it is necessary to provide a detection circuit for reading the wake-up signal from the multiplex communication signal in each communication node in the multiplex module, which complicates the circuit configuration of each communication node and increases the cost. There was a problem of doing.

In order to solve the above problem, a circuit dedicated to wake-up forming a wake-up signal and a line dedicated to wake-up transmitting a wake-up signal are separately provided, thereby simplifying the circuit configuration of each communication node. In order to reduce the cost, there has been proposed.

[0005]

However, in the multiplex communication system having the wake-up-only line, when the communication node ends the normal operation and can transition to the sleep state, that is, when the communication node enters the wake-up enable state, the wake-up occurs. The sleep determination information, that is, the operation release enable signal is transmitted to the other communication nodes using the dedicated line, and it is confirmed that the operation release enable signal is transmitted from all the communication nodes and all the communication nodes have entered the operation release enable state. After that, when an abnormality such as when the wake-up line is short-circuited to the vehicle body, for example, the operation release enable signal is not transmitted to other communication nodes, and all communication nodes enter the sleep state. Can no longer transition,
As the dark current of the vehicle increases, battery power is wasted,
There was a risk that the battery would go up.

An object of the present invention is to transmit sleep determination information of each communication node as a multiplex signal via a multiplex transmission line and a wake-up dedicated line so that when either the wake-up dedicated line or the multiplex transmission line is abnormal. Therefore, it is an object of the present invention to provide a multiplex transmission apparatus in which all communication nodes can transition to a sleep state even if the wake-up occurs, thereby preventing an increase in dark current.

[0007]

Means for Solving the Problems] multiplex transmission apparatus of the present invention, the transmit and receive control signals and the like via the multiplex transmission path 4
Both select wake-up state and sleep state
Can take on a plurality of communication nodes A, B, and C, and each of the communication nodes A, B, and wake-up circuit 3 provided and C, multi
Each wake-up circuit 3 is provided separately from the
, And communication nodes A, B,
C, an operation switch connected to its own communication node.
Wakes up its own communication node when switch 6 is operated
To the wake-up state.
An on / off signal is sent from the transmission paths 5 and 51 via the path 3
And transmits the signal to the transmission path via the wake-up circuit 3.
When the above ON / OFF signal is received from 5, 51,
Control means for shifting a communication node to a wake-up state
1 wherein each communication node A,
B, C, and own communication nodes A, B, C
Detecting means 11 for detecting that the loop is ready to be shifted
And each communication node A, B, C
Sleep method for causing the cards A, B, and C to shift to the sleep state
And the control means 1 comprises:
The communication node is in a sleep-enabled state due to
Is detected, the wake-up circuit 3
To the transmission paths 5 and 51 and the multiplex transmission path 4
The control means 1 transmits a reapable state detection signal.
Via the wake-up circuit 3, the transmission paths 5, 51
Alternatively, the sleep enable state is detected from the multiplex transmission line 4.
By receiving the knowledge signal, all communication nodes
When it is detected that the transition to the
By activating the sleep unit of its own communication node, the output from each detection unit is input to the release unit via the multiplex transmission path, and the output from the detection unit is also released via the transmission path. This means that all communication nodes can transition to the sleep state even if either the wake-up-only line or the multiplex transmission line has an abnormality, thereby preventing an increase in dark current. .

[0008]

1, a communication node A includes a microcomputer 1, a multiplex module 2 connected to the microcomputer 1 for inputting / outputting a control signal as a multiplex signal, and a microcomputer connected to the microcomputer 1. A wake-up circuit (wake-up means and signal forming means) 3 for waking up (starting up) 1 is provided, and the other communication nodes B and C have the same configuration.

Each of the multiplex modules 2 in the plurality of communication nodes A, B, C,... Is connected to each other via a multiplex transmission line 4 composed of a twisted pair line, and each wake-up dedicated circuit 3 is connected to a wake-up dedicated line. (Transmission path) 5,5
Are connected to each other via 1,.

The wake-up circuit 3 includes a transistor 31. The wake-up line 5 is connected to the collector of the transistor 31; the input side of the guarantee circuit 32; The output side of the circuit 32 is connected to the wake-up signal input port of the microcomputer 1, the base of the transistor 31 is connected to the wake-up signal output port of the microcomputer 1 via the resistor 34, and the emitter of the transistor 31 is grounded. Are connected in a wired OR manner among a plurality of communication nodes A, B, C,...

The microcomputer 1 is grounded via a switch 6 such as an ignition switch, and is a detecting means for detecting that the communication node A is in a state in which normal operation can be completed and a transition can be made to the sleep state, that is, in an operation-cancellable state. And a canceling unit for causing each communication node to transition to the sleep state, that is, canceling the operation according to the output (operation cancelable state detection signal) from the detecting unit of all communication nodes.

The assurance circuit 32 includes a power supply control circuit for maintaining the power supply voltage at a predetermined value, a protection circuit for protecting the microcomputer 1 in the event of a short circuit, an interrupt signal generation circuit for activating the microcomputer 1 from a low current mode, and the like. This is a circuit for reliably operating the microcomputer 1.

The operation will be described. In a sleep state in which power is not supplied to the multiplex module 2 (operation release state), the collector voltage of the transistor 31, that is, the voltage applied to the wake-up-only line 5 is a predetermined value.
When the switch 6 of the communication node A is turned on, the communication node A wakes up (starts) and the voltage applied from the output port of the microcomputer 1 to the base of the transistor 31 rises. Then, the transistor 31 is turned on with a predetermined time delay, the collector voltage of the transistor 31 drops, and as the collector voltage of the transistor 31 drops, the voltage of the wake-up-only line 5 drops to Lo (for example, 0 V). A wake-up signal which is an on / off signal (Hi-Lo in this embodiment) is issued.

In the case where another communication node receives the wake-up signal, a voltage drop signal, that is, a wake-up signal is applied to the input port of the microcomputer 1 via the guarantee circuit 32 of the wake-up circuit 3 in the communication node B. When input, the communication node B wakes up with a predetermined time delay, and further, since the voltage of the wake-up-only line 51 drops, the communication node C
, A voltage drop signal (wake-up signal) is input to the input port of the microcomputer 1 through the guarantee circuit 32 of the wake-up circuit 3, and the communication node C wakes up with a predetermined time delay. In the case where there are only three communication nodes B and C, the wake-up operation is completed when the communication node C wakes up as shown in the figure. The voltage applied to the base of the transistor 31 from the output port of the microcomputer 1 rises, and the transistor 31 is turned on. When there are three or more communication nodes as illustrated, a plurality of connected communication nodes are woken up in the same manner.

Each of the wake-up communication nodes performs a normal operation and enters a sleep state when the normal operation is completed. For example, when the communication node A completes all the normal operations and enters the sleep state, When the operation is released, the detection means 11 of the microcomputer 1 detects the operation release possible state, and the multiplex module 2 transmits the signals to the other communication nodes B, 5 via the multiplex transmission path 4 and the wake-up dedicated lines 5 and 51. When the communication node B completes the normal operation and enters the operation-cancellable state, the detecting means of the microcomputer detects the operation-cancellable state and sends the signal to the multiplexing module. An operation release possible state detection signal is transmitted to the release means 12 of the other communication nodes A and C via the multiplex transmission line and the wake-up dedicated line. When the normal operation of the communication node C is terminated and the operation of the communication node C can be released, the multiplex module releases the operation to the release means 12 of the other communication nodes A and B via the multiplex transmission line and the wake-up line. By transmitting the possible state detection signal, it is multiplexed that all the communication nodes A, B, and C have transmitted the operation release possible state detection signals, that is, that all the communication nodes A, B, and C are in the operation release possible state. When it is confirmed by receiving the operation release possible state detection signal from at least one of the transmission line 4 and the wake-up dedicated lines 5 and 51, all the communication nodes A, B and C are released (sleep) by the release means 12 respectively. The state is transited (see the time chart of FIG. 2).

The operation will be described with reference to the flowchart of FIG. 3. When the system of the multiplex transmission apparatus is started, if the wake-up switch 6 of the communication node A is on, the communication node A wakes up. As a result, the wake-up transistor 31 is turned on, and a start frame “1” indicating that the communication node A has been woken up is transmitted to the other communication nodes B and C, and the wake-up signal is transmitted to the wake-up dedicated lines 5 and 51 To the other communication nodes B and C to wake up the communication nodes B and C, respectively, and transmit an activation frame “1” to the effect that the communication node B has been woken up to the other communication nodes A and C,
An activation frame “1” indicating that the communication node C has been woken up is transmitted to the other communication nodes A and B, and the normal operation starts.

When the wakeup switch 6 of the communication node A is off and the wakeup switch 6 of the communication node B is on, the communication node B is woken up and the wakeup transistor 31 is turned on. The communication node B transmits the activation frame "1" to the effect that the communication node B has been woken up to the other communication nodes A and C, and sends a wake-up signal from the wake-up dedicated lines 5 and 51 to the other communication nodes A and C. To wake up the communication nodes A and C, respectively, and transmit an activation frame "1" indicating that the communication node A has been woken up to the other communication nodes B and C, and the communication node C has been woken up. The activation frame “1” to the effect that other communication nodes A and B
To enter normal operation.

When the wake-up switches 6 of the communication nodes A and B are off, the wake-up switch 6 of the communication node C must be on, so that the communication node C is woken up and waked up. The up-transistor 31 turns on, and the communication node C activates the activation frame “1”.
Is transmitted to the other communication nodes A and C, and a wake-up signal is transmitted from the wake-up dedicated lines 5 and 51 to the other communication nodes A and B to wake up the communication nodes A and B, respectively. Transmits an activation frame “1” indicating that the communication node B has been woken up, and transmits an activation frame “1” indicating that the communication node B has been woken up to the other communication nodes A and C. To enter normal operation.

After the normal operation is completed, each communication node A, B, and C is ready to enter the sleep state, that is, when the detecting means detects that the operation state has been released, all the communication nodes A , B and C individually transmit an activation frame "0" to the communication nodes other than themselves via the multiplexing module 2, the multiplexing transmission line 4, and the wake-up dedicated lines 5 and 51 as the operation release detectable signal. A communicates to other communication nodes B and C with communication node B
Is transmitted to the other communication nodes A and C, and the communication node C is transmitted to the other communication nodes A and B. After confirming that the activation condition of each of the communication nodes A, B and C is not satisfied, each communication node A ,
When the release frame 12 for B and C receives an activation frame "0" as an operation release detectable signal from all communication nodes other than itself via at least one of the multiplex transmission line 4 and the wake-up dedicated lines 5 and 51. Then, the release means 12 operates to transit to the operation release state (sleep state).

[0020]

Since the present invention is configured as described above, it has the following effects. Even if either the wake-up-only line or the multiplex transmission line causes the above, all communication nodes can transition to the sleep state, so that an increase in dark current can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a multiplex transmission apparatus of the present invention.

FIG. 2 is a time chart showing the operation of the multiplex transmission device of the present invention.

FIG. 3 is a flowchart showing the operation of the present invention.

[Explanation of symbols]

 A, B, C communication nodes 1 microcomputer 2 multiplex module 3 wake-up circuit 4 multiplex transmission line (twisted pair line) 5, 51 wake-up dedicated line 6 wake-up switch 11 detection means 12 release means 31 wake-up transistor

Continuation of the front page (72) Inventor Hitoshi Nakajima 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Naldec Co., Ltd. (56) References JP-A-57-160236 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) B60R 16/02 665 H04L 5/22 H04Q 9/00 301

Claims (1)

(57) [Claims] 1. A wake-up state and a sleep state while transmitting and receiving a control signal and the like via a multiplex transmission line 4.
And a plurality of communication nodes A, B, and C that can selectively adopt
Wake-up times provided for each communication node A, B, C
Path 3 and multiplex transmission path 4 are provided separately.
Transmission paths 5 and 51 connected to the
Nodes A, B, and C, and are connected to their own communication nodes.
Communication node when the operation switch 6 is operated
To the wake-up state and
From the transmission paths 5 and 51 via the backup circuit 3
An off signal is transmitted, and through the wake-up circuit 3
The on / off signal is received from the transmission paths 5 and 51.
Sometimes the node goes into wake-up state
A multiplex transmission apparatus comprising
Provided in nodes A, B, and C, and their own communication nodes A,
A detection for detecting that B and C are in a state capable of shifting to sleep.
The communication means 11 and each of the communication nodes A, B, and C,
The own communication nodes A, B, and C shift to the sleep state.
And a sleep unit 12. The control unit 1 includes the sleep unit 12.
The own communication node can shift to sleep by the informing means 11
State is detected, the wake-up
The transmission paths 5 and 51 and the multiplex transmission
A sleep enable state detection signal is transmitted to the transmission path 4 and the above control is performed.
Means 1 transmits the signal via the wake-up circuit 3
The sleep from the paths 5 and 51 or the multiplex transmission path 4
By receiving the possible state detection signal, all communication
Detected that the card was ready to go to sleep
Sometimes the above sleep means of its own communication node is activated
Multiplex transmission apparatus characterized by causing.