Control device for connecting a CAN bus to a radio network, and motor vehicle having such a control device

Abstract

A control device and corresponding motor vehicle for connecting a CAN bus to a radio network, having the following features: the control device includes a wireless controller, a microcontroller, a first CAN transceiver and a second CAN transceiver; the microcontroller is connected, on the one hand, to the wireless controller and, on the other hand, to the CAN transceivers; the first CAN transceiver is connected to the second CAN transceiver; the first CAN transceiver is configured in such a manner that it suppresses transmission via the CAN bus and supports reception via the CAN bus in a normal mode and supports transmission and reception in a diagnostic mode; and the second CAN transceiver is configured in such a manner that it changes the first CAN transceiver from the normal mode to the diagnostic mode when the second CAN transceiver receives a wake-up frame via the CAN bus.

Claims

1. A control device for connecting a controller area network (CAN) bus to a radio network, comprising: a wireless controller, a microcontroller, a first CAN transceiver and a second CAN transceiver, the microcontroller is connected to the wireless controller and the CAN transceivers, the microcontroller and the second CAN transceiver have a serial peripheral interface, wherein the serial peripheral interface is configured for self-holding separation by an asynchronous level-controlled flip-flop, the microcontroller has a binary control output (out) which is connected to a set input (S) of the asynchronous level-controlled flip-flop, and the microcontroller controls the separation by the control output (out), the first CAN transceiver is connected to the second CAN transceiver, the first CAN transceiver is configured to (i) suppress transmission (Tx) via the CAN bus and support reception (Rx) via the CAN bus in a first mode in which CAN transmissions are suppressed, and (ii) support transmission (Tx) and reception (Rx) in a second mode in which CAN transmissions are enabled, the second CAN transceiver is configured to change the first CAN transceiver from the first mode to the second mode when the second CAN transceiver receives (Rx) a wake-up frame via the CAN bus, the microcontroller is programmed such that it initially configures the wake-up frame via the serial peripheral interface.

2. The control device as claimed in claim 1, wherein: the first CAN transceiver has an activation input (EN), the second CAN transceiver has a blocking output (INH), the activation input (EN) is connected to the blocking output (INH), the first CAN transceiver is configured in such a manner that the activation input (EN) activates a diagnostic mode, and the second CAN transceiver is configured in such a manner that he wake-up frame activates the blocking output (INH).

3. The control device as claimed in claim 1, wherein: the microcontroller is programmed in such a manner that the microcontroller initially configures the wake-up frame via the serial peripheral interface.

4. The control device as claimed in claim 1, wherein the serial peripheral interface includes transistor circuits connected to the asynchronous level-controlled flip-flop such that the transistor circuits cause the separation.

5. The control device as claimed in claim 1, wherein the first CAN transceiver is a TJA1041A.

6. The control device as claimed in claim 1, wherein the second CAN transceiver is an E520.13.

7. The control device as claimed in claim 6, wherein four inputs of the E520.13 implement the serial peripheral interface.

8. A motor vehicle having a control device as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) One exemplary embodiment of the invention is illustrated in the drawing and is described in more detail below.

(2) FIG. 1 shows the simplified circuit diagram of a control device according to aspects of the invention.

(3) FIG. 2 shows the connection assignment of a first CAN transceiver used in the control device.

(4) FIG. 3 shows the connection assignment of a second CAN transceiver used in the control device.

DETAILED DESCRIPTION OF THE INVENTION

(5) FIG. 1 illustrates the fundamental structure of a vehicle control device 10 according to one embodiment of the invention. The control device includes a wireless controller 12, a microcontroller 14, a first CAN transceiver 16, and a second CAN transceiver 18. In contrast to conventional circuits of this type, a second wake-up CAN transceiver of the E520.13 type is used according to aspects of the invention in the control device 10 for wireless data transmission in order to avoid manipulation of the CAN bus communication.

(6) CAN messages are transmitted and received via the first CAN transceiver 16 of the TJA1041 type. Apart from the case of diagnosis, this first CAN transceiver 16 suppresses any transmission via the CAN bus (listen-only mode). The output INJ=1 is set only if the second CAN transceiver 18 receives (receive, Rx) the diagnostic request, as a result of which the first CAN transceiver 16 is changed to the diagnostic mode.

(7) In order to set the diagnostic request as a wake-up frame, the microcontroller 14 configures the wake-up frame of the second CAN transceiver 18 via the serial peripheral interface SPI after the ignition has been switched on, that is to say during initialization. The lines of the serial peripheral interface SPI must then be separated in a self-holding manner by a self-holding separation 20 (such as an asynchronous level-controlled flip-flop; e.g., an S/R flip-flop) in order to avoid subsequently changing the wake-up frame. For this purpose, the microcontroller 14 changes the binary output from 0 to 1 at the end of the initialization. As a result, the S/R flip-flop is set from 0 to 1 in a self-holding manner. The lines are separated by transistor circuits when the S/R flip-flop is set. The S/R flip-flop may be an asynchronous level-controlled flip-flop.