Mazda Motor Corporation

The Furukawa Electric Co., Ltd.

Furukawa Electric., Ltd.

Hiroaki Sakamoto

Yutaka Matsuda

Yoshikazu Nobutoki

Hiroo Moriue

Seiji Hirano

Kyosuke Hashimoto

Koji Terayama

Eiji Ichii

Osamu Michihira

Kiyoshi Inoue

Hideki Kimura

Tetsuhiro Yamashita

Tomoji Izumi

Shinshi Kajimoto

Shigetoshi Doi

Toshiaki Kawanishi

Toshifumi Ikeda

Toshitaka Hara

Hideki Nakazono

Yoshito Watanabe

Mitsuru Akimoto

Koji Umegaki

Hiroyuki Sumihara

A multiplex transmission apparatus, having a communication control circuit for carrying out transmit-receive control of a frame of data transmitted through a bus, and an output port for outputting data in frame received by the communication control circuit. The multiplex transmission apparatus is operated by a power supply voltage supplied from a power supply circuit to perform data communication with another multiplex transmission apparatus via a bus. First and second low voltage detection circuits, when detecting preset voltage values V.sub.L and V.sub.R of a power supply voltage, reset the communication control circuit and the output port. This multiplex transmission apparatus keeps the output of the output port in a normal condition despite relatively small variations in the power supply voltage (i,e., where V.sub.L .gtoreq.power supply voltage&gt;V.sub.R).

Multiple transmission apparatus

A multiplex data communication system including a number of communication nodes interconnected through a transmission path, each of which includes a data transmitting/receiving circuit providing a reception signal representative of normal data reception from another communication node and a transmission signal representative of normal data transmission therefrom, and a data operation circuit for controlling an electronic equipment unit associated with each communication node based on the data from the other communication node and generating the data relating to each communication node which is transmitted by the data transmitting/receiving circuit, the data operation circuit making a judgement of normality of a data communication function of each communication node based on at least one of the data reception signal and data transmission signal.

Multiplex data communication system

A multiplex transmission system includes a plurality of multiplex nodes interconnected by a common multiplex transmission line. Data frames are transmitted among the multiplex nodes through the multiplex transmission line. A data frame transmitted from a sending multiplex node includes a data area which is divided into subdivided areas in accordance with data transmitted therefrom and data transmitted from receiving multiplex nodes which send data in response to a send request, in accordance with the number of data pieces or the number of bits, and the receiving nodes send data to respective subdivided areas in a predetermined order, to thereby carry out a data transmission. Accordingly, the sending multiplex node can simultaneously collect data from the receiving multiplex nodes which are functionally subordinate. When any of the receiving multiplex nodes fails to return an ACK signal, the sending multiplex node retransmits the data frame.

Multiplex transmission system having plurality of nodes and common

When a message is transmitted, frame by frame, from any one (10) of a plurality of multiplex nodes to a common multiplex bus (MB) to which the multiplex nodes are connected, each of the multiplex nodes (20 and 30) determines that transmission of a frame therefrom is allowed when it detects a transmission permission signal (b, b') added to the frame after detection of and idle state of the multiplex bus, and starts transmitting a message data frame. This makes it possible to properly implement priority-based control according to the priority levels of the data frames irrespectively of variations in the reference clocks of the multiplex nodes. Further, receiving multiplex nodes perform frame synchronization at the rise of a special code (a) of a start code (SOM) of a message data frame, and then perform re-synchronization at the rise of a special bit pattern (b') which includes a passive bit and a dominant bit. This prevents synchronization from being deviated and bit errors resulting from deviated synchronization, thus leading to higher reliability of multiplex transmission.

Multiplex transmission method and a synchronizing method in multiplex

A multiplex transmission apparatus includes a communication control circuit connected to a bus for successively receiving data from the bus, and the received data is output from an output port to a load via an output circuit. The successively received data is once stored in a receiving buffer and is then transferred to the output port. A port control circuit, which is connected to the output port, monitors the data transferred to the output port. When at least part of the data does not change in a predetermined manner in response to the data received immediately before, the port control circuit controls data outputted from the output port so that loads controlled according to the data from the output port are held in a safe state.

Method and apparatus for multiplex transmission

A multiplex transmission system of this invention includes a plurality of multiplex nodes interconnected by a common multiplex transmission line. A frame of data is transmitted among the multiplex nodes through the multiplex transmission line. When a data frame transmitted from an air conditioner switch multiplex node (subnode) is received, an air conditioner unit multiplex node (main node), which is predetermined as a destination node, detects the contents of each data from an ID-a of the received data, performs a calculation on SOM to DATA 4 received, generates collation data (CRC) in accordance with the result of the calculation and transmits same. The subnode generates collation data (CRC), which is an error check code, through a calculation on the transmitted SOM to DATA 4, and compares the thus-generated CRC with the CRC received from the main node, to determine whether or not the data transmission was properly carried out. When the data transmission was carried out properly, the subnode returns a signal ACK3, and when the data transmission failed, the data frame is retransmitted, whereby the subnode need not have an ACK management function.

Multiplex transmission system

A multiplex transmission system of this invention includes a plurality of multiplex nodes interconnected by a common multiplex transmission line. A plurality of groups of different combinations of the multiplex nodes are predetermined, and a frame of data is transmitted among the multiplex nodes through the multiplex transmission line. The data frame includes a group specifying area specifying a group of nodes from which an acknowledge signal is to be returned. When a data frame transmitted from a sending node is received, each multiplex node determines whether or not it belongs to the group specified by bits in the group specifying area of the transmitted frame. When the data frame is properly received, only those multiplex nodes which belong to the specified group return the acknowledge signals to an acknowledge signal area in the data frame in accordance with the bits in the group specifying area, whereby the transmission efficiency is improved.

The data storing system according to the present invention is used for a communication control circuit. The communication control circuit is equipped with a communication sequencer, which takes in a message to be transmitted to a multiplex bus, an ID table which registers data IDs of messages necessary for the station, and the first and second memory circuits which have memory areas keyed to the data IDs. When the communication sequencer takes in a message, it determines whether its data ID exists in the ID table. If the data ID exists and the frequency of occurrence is high, then data following the data ID is temporarily stored in a memory area keyed to a data ID of the first memory circuit. If the data ID exists and the frequency of occurrence is low, then the data following the data ID is temporarily stored in a memory area of the second memory circuit. When a CPU reads the aforementioned stored data, it sets the status area of the storage area, in which the data was stored, for a state that enables a data storage change.

Data storing system for a communication control circuit

A multiplex transmission system according to this invention includes a plurality of multiplex nodes connected to one another via a common multiplex bus, for effecting data transfer between the nodes. When reception nodes correctly receive data transmitted from one of the nodes for each frame, each of the reception nodes returns an ACK signal to the multiplex bus, registers all of the nodes connected to the multiplex bus into the ACK table in response to the ACK signal, and effects the ACK management. In this case, for example, if a door FR multiplex node causes an interruption to transmit a frame while an air-conditioning unit multiplex node is retransmitting a frame, the air-conditioning unit multiplex node effects the ACK management without regarding the ACK signal for the interruption frame as an object of the updating logic of its own ACK table.

A receipt acknowledgement method which is applied to a multiplex transmission system provided with a plurality of multiple nodes (11 to 17) connected to one another through a multiplex bus (18), and is capable of conducting efficient data transmission, and in which a transmitting multiplex node (13) sends out a frame and, after entry into an ACK signal area of the frame, sends out a delimiter sign consisting of passive and active two bits with a four-bit interval, thereby dividing the acknowledgement signal area. The receiving multiplex nodes (11, 12, 14 to 17) are synchronized according to an active bit sent out from the transmitting multiplex node (13), and returns ACK signals to the ACK signal area in the predetermined order when data transfer on the transmission request frame has been normally performed, whereby data transmission can be conducted at high speed with improved efficiency.

Receipt acknowledgement method in multiplex transmission

A valve mechanism is provided in a hydraulic line which connects a master cylinder of a brake system and a brake provided for a driving wheel of a vehicle. When the slip of the driving wheel is larger than a predetermined value, the valve mechanism is selectively moved between a position where it directly applies brake fluid from the master cylinder to the brake and a position where it returns brake fluid discharged from the brake to an oil reservoir, thereby controlling the driving torque of the driving wheel to converge the slip of the driving wheels to a proper level. An oil pump is operated to return the brake fluid in the oil reservoir to the master cylinder when the valve mechanism is operated to effect the slip control. While the brake pedal is in the released state, the oil pump is kept operated during the slip control and for a predetermined time after interruption of the slip control so that the brake fluid in the oil reservoir is returned to the master cylinder substantially completely. When the brake pedal is depressed while the slip being effected, the slip control is ended and the oil pump is stopped. After the brake pedal is released, the oil pump is operated for a predetermined time.

Slip control system for vehicle

An automobile air conditioning device includes a ventilation system with a ventilation fan for discharging air contained in a passenger chamber from the vehicle. A dew condensation detector is adapted to detect a predetermined relative humidity for a dew point at which dew condensation on a rear window glass of the vehicle is presumed to occur. A controller actuates the ventilation system when the dew condensation detector detects the dew point while the vehicle is running.

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Fukuyama, Japan

Hiroaki Sakamoto