DE102017206635A1 - Method for controlling the awakening of a bus system - Google Patents

Abstract

The invention relates to a method for controlling the awakening of a bus system with a number of bus terminals, which is coupled via a transceiver (114) to a controller (112) of a control unit, wherein the number corresponding to the number of bus connections via the transceiver (114) is output on signals, the signals are converted by means of a digital-to-analog converter so that an analog signal (190) results, which carries information about the signals and which is evaluated and turned on based on the evaluation of the controller (112) becomes.

Description

The invention relates to a method for controlling the awakening of a bus system and a control device for carrying out the method. The method and the control unit are used in particular in connection with a LIN bus or a CAN bus.

State of the art

In motor vehicles, different bus systems are used for communication. Low data rate communication typically uses LIN (Local Interconnect Network) (LIN) bus systems, which are a serial communication system for interconnecting sensors and actuators. Such a communication system is also referred to as fieldbus.

Typically, a LIN bus comprises a master, which is regularly designed as a microcontroller, and one or more slaves. The master determines the chronological order of all messages by sending out their beginning, the so-called header. Two states of the LIN bus are provided, namely the sleep mode and the active or normal mode. The transition between the two modes is initiated on the one hand with a command of the master and on the other hand via a wake-up or wake-up signal frame by the master or one of the slaves.

If connected stations and the LIN bus are in idle status, the bus system must be awoken by the connected controller. This is done by pulling a RxD line from a 5V sleep level transceiver to ground. If the RxD cable is connected to a wake-up port pin of a controller and the controller is powered on in idle mode, it may cause the controller to wake up. It is on this 1 directed.

When using a controller from the powertrain or powertrain range, the supply of the controller in idle mode for quiescent power reasons is not possible. In this case, on the one hand the RxD signal between the transceiver and the controller must be disconnected in idle mode and on the other hand, the detection of the awakening LIN bus from a separate hardware, eg. B. a second controller, performed. This can then wake the system to the system base chip via the wake-up or WAKE line.

From the publication DE 103 58 584 A1 For example, a method for waking participants of a bus system is known. In the method, a counter is used which comprises at least one predetermined signal property of the signals transmitted on the bus system. Upon reaching a predetermined number, based on the signal property, this initiates the further wake-up process. With the described method it is achieved to selectively wake participants in the bus system.

The publication EP 2 380 315 B1 describes a method for controlling the awakening of subscribers of a network or bus system in which unintentional awakenings are counted. Each time the subscriber wishes to issue a network waking command to the network, the value of a running counter is determined. If the current value is greater than or equal to a predetermined threshold, the subscriber is prohibited from executing the command.

Disclosure of the invention

Against this background, a method according to claim 1 and a control device according to claim 7 are presented. Embodiments emerge from the dependent claims and from the description.

The method is typically used in a control unit which is connected to a bus system, for example a LIN bus or a CAN bus. The connection or coupling takes place regularly via a transceiver. This is connected to a controller or a main controller of the controller. The method is used to wake up the bus system, which has a number of bus connections or bus channels.

In the idle mode of the bus system, the connections of the transceiver to the controller are disconnected or interrupted. Now one of the participants wakes up the bus system, a corresponding signal is set. Depending on the number of bus connections thus a corresponding number of signals must be evaluated. These signals are now combined, typically via a digital-analogue Translator, so that an analog signal is generated, which in turn carries the information about which of the bus connections, the waking is initiated. For this evaluation, a second controller can be used, which in turn gives a corresponding wake-up signal to a system-based chip, which then activates the controller and informed about it. The controller is switched off before. Thus, the controller is turned on based on the evaluation or the control unit awakened.

The presented control unit has a controller and a transceiver, via which a bus system, for example a LIN bus or a CAN bus, is coupled to a number of bus connections.

The secondary controller is usually an 8 or 16 bit controller. As a bus system in addition to a LIN bus, a CAN bus and other suitable bus systems into consideration.

With the presented method, it is possible to reduce the number of lines and the required pins on the second controller or to avoid a multiplexer as a port expansion. Furthermore, the required PCB space for the routing (PCB: Printed Circuit Board) is reduced.

In order to achieve this, it is provided, for example, in the case of a LIN bus, to convert the quasi-digital states of the RxD signals into a single analog signal with 2n analog stages. For this example, an R2R network can be used, as is known from digital-to-analog converters. This makes every digital state combination in the analog signal recognizable and each aroused LIN individually recognizable.

An R2R network is a network made up of resistors with the values R and 2R. The individual input bits are either grounded or referenced and feed twice as large a resistance (2R) as the horizontal part (R) of the network. Each bit thus contributes a specific part to the resulting output voltage.

By way of example, a reduction of 4 to 1 is possible. An embodiment of this is in 2 shown. The evaluation of the remaining line on the second controller should be done analogously.

The transceiver is a kind of adapter to the LIN bus system, with the signals can be coupled into the bus system and decoupled from this. This is responsible for the transmission and reception of signals.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination but also in other combinations or in isolation, without departing from the scope of the present invention.

list of figures

• 1 shows a block diagram of a control unit with a main controller, which is coupled via a transceiver with a LIN bus system, according to the prior art.
• 2 shows a block diagram of an embodiment of the presented controller with a main controller, which is coupled via a transceiver with a LIN bus system, for carrying out the method described.

Embodiments of the invention

The invention is schematically illustrated by means of embodiments in the drawings and will be described in detail below with reference to the drawings.

1 shows a control unit, the whole with the reference numeral 10 is designated. This includes a main controller 12 , a transceiver 14 , via which a bus system, in this case a LIN bus system, is connected, a system-based chip 15 and a second controller 16 , Furthermore, the illustration shows four pull-up resistors 18 ,

The transceiver 14 includes first connections 20 for the output of signals RxD, second connections 21 for signals TxD and an output 22 for the signal INH (inhibit). This signal signals a wake-up process on one of the LIN buses connected to the transceiver.

The system base chip 14 has an entrance 30 for a wake-up signal, a first output 32 for a supply of permanent 5V and a second output 34 for a supply of 5V, which is off in sleep mode.

The second controller 16 has an exit 40 for the wake-up signal and four inputs 42 for the RxD signals.

The system base chip 15 contains one or more power supplies for the main controller 12 and further modules of the control unit 10 , He also controls the supply according to the requirement in the operating states "sleep" and "active operation". By way of example, he activates the supply of the main controller here 12 due to the wake-up signal at the input 30 , The system base chip 15 can also be implemented in separate blocks or supply modules.

The main controller 12 has a first entrance 50 for the supply of 5V, which is off in sleep mode, and four other inputs 52 for the RxD signals. You can also see in the connections 54 between the transceiver 14 and the main controller 12 switch 56 that are open in sleep mode, as by a circling 58 is clarified.

The switches 56 are open in idle mode, closed in active mode. The activation should be parallel to the activation or supply of the main controller 12 respectively.

The illustrated transceiver 14 is a 4-way LIN transceiver on a powertrain controller, the main controller 12 which is unaided in sleep mode. Detecting the awakening LIN bus is done by monitoring the RxD signals through the secondary controller 16 , This can be over the system base chip 15 the system or the control unit 10 In the event of an error or, for example, in the event of inadmissible, frequent wake-up events by LIN slaves, deactivate the wake-up capability of a single LIN and suppress the wake-up processes.

The use of the INH output 22 of the transceiver 14 it is not sufficient to control the awakening, because then a single LIN can not be switched off as the cause of the wake-up.

It is now proposed, instead of the digital evaluation of each RxD line to supply these signals to a digital-to-analog converter or converter, such as, for example, an R2R network. The steps in the analog signal represent all occurring signal level combinations of the RxD lines.

2 shows a control unit, the whole with the reference numeral 100 is designated and which is set up to carry out the presented method. This includes a main controller 112 , a transceiver 114 via which a bus system, in this case a LIN bus system is connected, a system-based chip 115 and a second controller 116 , Furthermore, the illustration shows four pull-up resistors 118 ,

The transceiver 114 includes first connections 120a to 120d for input and output of signals RxD1, RxD2, RxD3, RxD4, second connections 121 to 121d for signals TxD1, TxD2, TxD3 TxD4 and one output 122 for the signal INH.

The system base chip 115 has an entrance 130 for a wake-up signal, a first output 132 for a supply of permanent 5V and a second output 134 for a supply of 5V, which is off in sleep mode.

The second controller 116 has an exit 140 for the wake-up signal and an input 142 for an analog signal 190 resulting from the combination of the RxD signals.

The system base chip 115 contains one or more power supplies for the main controller 112 and further modules of the control unit 100 , He also controls the supply according to the requirement in the operating states "sleep" and "active operation". By way of example, he activates the supply of the main controller here 112 due to the wake-up signal at the input 130 , The system base chip 115 can also be implemented in separate blocks or supply modules.

The main controller 112 has a first entrance 150 for the supply of 5V, which is off in sleep mode, and four other inputs 152a to d for the RxD signals. You can also see in the connections 154a to d between the transceiver 114 and the main controller 112 switch 156a to d, which are open in idle mode, as by a circling 158 is clarified.

The switches 156 are open in idle mode, closed in active mode. The activation should be parallel to the activation or supply of the main controller 112 respectively.

The illustration also shows an R2R network 180 with first resistances 182 , which have the value R, and second resistances 184 that the value 2R to have. This R2R network 180 represents a digital-to-analog converter, which converts the signals RxD1 to RxD4 into the analog signal 190 convert.

This analog signal 190 thus becomes the second controller 116 recorded and evaluated. Depending on this, a wake-up signal is sent through the output 140 and the entrance 130 the system base chip 115 given to this, in turn, the main controller 112 can supply accordingly.

The system base chip 115 is only optional, it can also directly the power supply or the voltage regulator for the main controller 112 to be activated.

The evaluation of the states of the RxD lines takes place via the assignment according to the following table: RxD1 RxD2 RxD3 RXD4 analog signal 1 1 1 1 VCC 1 1 1 0 14/15 * VCC 1 1 0 1 13/15 * VCC 1 1 0 0 12/15 * VCC etc. 0 0 1 0 2/15 * VCC 0 0 0 1 1/15 * VCC 0 0 0 0 0V

VCC is the supply voltage of the pullups R_Rx_Pullup.

Because the high level on the RxD lines only through the pullup resistors 118 is generated, ie open-collector stage to ground in the transceiver, the current load through the R2R network 180 be kept low. This means R or 2R must be large compared to R_Rx_Pullup, eg. B. R = 25 kohms. Otherwise, the state detection is no longer unambiguous and the voltage level at a RxD signal is too much influenced by the adjacent signal states.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10358584 A1 [0006]
• EP 2380315 B1 [0007]

Claims (10)

A method of controlling the wake-up of a bus system having a number of bus terminals coupled via a transceiver (114) to a controller (112) of a controller (100) at which a number corresponding to the number of bus terminals is provided through the transceiver (114) Signals is output, the signals are converted by means of a digital-to-analog converter so that an analog signal (190) results, which carries information about the signals and which is evaluated and is turned on based on the evaluation of the controller (112) , Method according to Claim 1 in which an R2R network (180) is used as a digital-to-analog converter. Method according to Claim 1 or 2 in which the analog signal (190) is evaluated by a second controller (116). Method according to Claim 3 in that the second controller (116) sends a wakeup signal to a system base chip (115), which in turn passes a corresponding signal to the controller (112) Method according to one of Claims 1 to 4 which is used in conjunction with a LIN bus. Method according to one of Claims 1 to 4 which is used in conjunction with a CAN bus. A controller comprising a controller (112) and a transceiver (114) via which a bus system is coupled to a number of bus ports connected to the controller (112) via the transceiver (114), wherein via the transceiver (114) the number of the bus terminals corresponding number of signals is output, wherein a digital-to-analog converter is provided which converts the signals so that an analog signal (190) results, which carries information about the signals and is to be evaluated and based the evaluation of the controller (112) is turn on. Control unit after Claim 7 in which a R2R network (180) serves as digital-to-analogue converter. Control unit after Claim 7 or 8th in which a second controller (116) is provided for evaluating the analog signal (190). Control unit according to one of Claims 7 to 9 in which a system-based chip (115) is provided.

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