Single-processor system

• US 6,526,527 B1
• Filed: 10/13/1999
• Issued: 02/25/2003
• Est. Priority Date: 10/17/1998
• Status: Expired due to Term

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: DaimlerChrysler AG (Mercedes-Benz Group AG)
• Inventors: Volk, Gert, Gall, Richard, Maier, Thomas, Schmid, Erwin, Trost, Jurgen
• Primary Examiner(s): Baderman, Scott
• Assistant Examiner(s): Wilson, Yolanda L
• Application Number:
  US09/416,770
• Time in Patent Office: 1,231 Days
• Field of Search: 714/55, 714/10, 714/23, 714/51
• US Class Current: 714/55
• CPC Class Codes: G05B 19/0428 Safety, monitoring G05B19/0423 takes precedence
• CPC Class Codes: G05B 2219/25158 Watchdog
• CPC Class Codes: G06F 11/0757 by exceeding a time limit, i.e. time-out, e.g. watchdogs

Abstract

A single processor system features independent multiple watchdog units allocated to a processor unit of the system, the watchdog units operable to monitor for system faults and, upon detecting a fault, further operative to place the processor system into a predetermined fault reaction state. The multiple watchdog units are each provided with respective different watchdog calls which are output to the processor unit depending upon program execution.

Claims

1. Single-processor system for carrying out a required system function, particularly for performing a safety-critical control function, having

a processor unit for carrying out the required system function, and

a fault reaction means which monitor the processor system for system faults occurring and have at least two watchdog units which are allocated to the processor unit to monitor faults and which, if a fault is discovered, put the processor system into a predetermined fault reaction state, wherein;

the two watchdog units are provided with different watchdog calls which are output by the processor unit depending on program execution;

wherein said system includes an actuator driven by said processor unit and putting said processor system into a fault reaction involves a first fault recognition by one of said at least two watchdogs units which recognizes said first fault and puts said actuator into a state which is predetermined for said first fault and a second fault recognition by another one of said at least two watchdog units which recognizes the second fault and puts the actuator into said state which is predetermined.

2. Single-processor system according to claim 1, further characterized in that the watchdog unit which recognizes the fault keeps the actuator in the predetermined state until said watchdog unit obtains enable information from the processor unit.

3. Single-processor system according to claim 2, further characterized in that the watchdog calls are implemented at at least one point in the program execution performed by the processor unit, and the watchdog units contain execution checking means which check that a respective watchdog call is received correctly and, in the event of a faulty call, deduce that a system fault has occurred.

4. Single-processor system according to claim 1, further characterized in that the watchdog calls are implemented at at least one point in the program execution performed by the processor unit, and the watchdog units contain execution checking means which check that a respective watchdog call is received correctly and, in the event of a faulty call, deduce that a system fault has occurred.