Method for operating a bus control unit, and bus control unit

• US 9,494,999 B2
• Filed: 07/01/2011
• Issued: 11/15/2016
• Est. Priority Date: 07/31/2010
• Status: Active Grant

• Current Assignee: Audi AG (Volkswagen AG)
• Original Assignee: Audi AG (Volkswagen AG)
• Inventors: Hartmann, Juergen, Nagy, Guenther, Spaeth, Karl
• Primary Examiner(s): Abbaszadeh, Jaweed A
• Assistant Examiner(s): Corcoran, Brian J
• Application Number:
  US13/813,544
• Publication Number:
  US 20130205145A1
• Time in Patent Office: 1,964 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 1/3253 Power saving in bus
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04L 12/40026 Details regarding a bus guardian
• CPC Class Codes: H04L 12/40039 Details regarding the setting of the power status of a node according to activity on the bus
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• CPC Class Codes: H04L 2012/40215 Controller Area Network CAN
• CPC Class Codes: H04L 2012/4026 Bus for use in automation systems
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A watchdog function is performed for those messages which are used by a controller in a CAN bus to keep the other controllers active. All emitted keep-active messages are read again by the emitting controller itself and are checked for the presence of a reason. In the absence of such a reason, a restart is carried out.

Claims

1. A method for operating a first controller which is connected to a vehicle bus, comprising:

emitting, by a keep-active device, a keep-active message from the first controller to maintain communication with at least a second controller connected to the vehicle bus, by a method comprising;

using at least a first bit in the keep-active message to keep the second controller active; and

using at least a second bit in the keep-active message to communicate a reason for keeping the second controller active, the second bit being included in the keep-active message during proper operation of the first controller;

reading at the first controller, all keep-active messages emitted on the vehicle bus by the keep-active device and checking at the first controller, by a check device, whether the second bit is included in the keep-active message to determine whether the reason for keeping the second controller active has been communicated; and

if the second bit is not included in the keep-active message, resetting, by the check device, at least one of a software function and a component function of the first controller,

wherein

the keep-active device includes a processor and an emitting unit that is operated by the processor to emit the keep-active messages to the second controller,

the check device includes a software unit which is independent from the emitting unit which checks whether the second bit is included in the keep-active message to determine whether the reason for keeping the second controller active has been communicated in the keep-active messages emitted by the emitting unit, and

the check device is inactive when no keep-active message has been emitted.

2. The method according to claim 1, wherein, if the second bit is not included in the keep-active message, a program currently being executed by the first controller is restarted.

3. The method according to claim 1, wherein

the first controller has a processor, and

if the second bit is not included in the keep-active message, the processor of the first controller is completely reset.

4. The method according to claim 1, further comprising using at least the first bit in the keep active message to keep a third controller active.

5. The method according to claim 1, wherein

the resetting comprises restarting a program currently being executed by the first controller.

6. The method according to claim 1, wherein

the reason for keeping the second controller active corresponds to a bit value of the second bit in the keep-active message and the bit value of the second bit indicates the reason for keeping the second controller active.

7. The method according to claim 6, wherein

the bit value of the second bit indicates the reason for keeping the second controller active is to inform the second controller that cooperation of the second controller with the first controller is required for execution of a task by the first controller.

8. The method according to claim 1, wherein if the check device resets the at least one of the software function and the component function of the first controller as a result of determining the second bit is not included in the keep-active message when the emitting unit emits the keep-active message a first time, the method further comprises emitting the keep-active message a second time after the check device resets the at least one of the software function and the component function of the first controller.

9. A first controller to connect to a vehicle bus, comprising:

a keep-active device to emit keep-active messages to keep second controllers on the vehicle bus active, the keep-active messages being emitted to the second controllers and including at least a first bit to keep the second controllers active and at least a second bit to communicate a reason for keeping the second controllers active; and

a check device to read all keep-active messages emitted on the vehicle bus by the keep-active device, to check whether the second bit is included in each keep-active message to determine whether the reason for keeping the second controllers active has been communicated in the keep-active messages and, if the second bit is not included in the keep-active message, to reset at least some functions of the first controller,

wherein

the keep-active device includes a processor and an emitting unit that is operated by the processor to emit the keep-active messages to the second controllers,

the check device includes a software unit which is independent from the emitting unit which checks whether the second bit is included in the keep-active message to determine whether the reason for keeping the second controllers active has been communicated in the keep-active messages emitted by the emitting unit, and

the check device is inactive when no keep-active message has been emitted.

10. The first controller according to claim 9, wherein

if the second bit is not included in the keep-active message, the check device restarts a program currently being executed by the first controller.

11. The first controller according to claim 9, wherein

the reason for keeping the second controllers active corresponds to a bit value of the second bit in the keep-active messages and the bit value indicates the reason for keeping the second controllers active.

12. The first controller according to claim 11, wherein

the bit value indicates the reason for keeping the second controllers active is to inform the second controllers that cooperation of the second controllers with the first controller is required for execution of a task by the first controller.