Controlling real time during embedded system development

• US 20100011237A1
• Filed: 07/10/2008
• Published: 01/14/2010
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: Siemens Industry Software Limited (Siemens AG)
• Original Assignee: Mentor Graphics Corporation (Siemens AG)
• Inventors: Teegarden, Darrell A., Brooks, Lance S. P.
• Granted Patent: US 9,459,890 B2
• Time in Patent Office: Days
• US Class Current: 713/502
• CPC Class Codes: G06F 11/362 Software debugging
• CPC Class Codes: G06F 30/33 Design verification, e.g. functional simulation or model checking
• CPC Class Codes: G06F 30/3308 using simulation
• CPC Class Codes: G06F 30/331 with hardware acceleration, e.g. by using field programmable gate array [FPGA] or emulation
• CPC Class Codes: G06F 30/396 Clock trees
• CPC Class Codes: G06F 9/455 Emulation; Interpretation; Software simulation, e.g. virtualisation or emulation of application or operating system execution engines
• CPC Class Codes: G06F 9/45537 Provision of facilities of other operating environments, e.g. WINE I/O emulation G06F13/105

Abstract

Disclosed herein are representative embodiments of methods, systems, and apparatus that can used to control real-time events (e.g., the real-time clock) during the design, simulation, or verification of an embedded system. In one exemplary embodiment disclosed herein, for example, a real-time clock signal is generated and tasks defined by an embedded software application are triggered with the real-time clock signal. In this embodiment, the embedded software application is executed by an embedded processor with a real-time operating system (“RTOS”), and the real-time clock signal is controllable independent of a processor clock signal driving the embedded processor in a manner that allows the real-time clock to have a different time base than the processor clock.

Claims

1. A method, comprising:

generating a real-time clock signal; and

triggering tasks defined by an embedded software application with the real-time clock signal,

wherein the embedded software application is executed by an embedded processor with a real-time operating system (“

RTOS”

), and

wherein the real-time clock signal is controllable independent of a processor clock signal driving the embedded processor such that the real-time clock signal has a different time base than the processor clock signal.

2. The method of claim 1, wherein the real-time clock signal is generated by software running on a computer workstation.

3. The method of claim 2, wherein the software running on the computer workstation is an application running within a debugger or simulator.

4. The method of claim 1, wherein the real-time clock signal is generated by software running on another external embedded system.

5. The method of claim 1, wherein the real-time clock signal is generated by software that is running as a task within the embedded processor.

6. The method of claim 1, further comprising suspending the generation of the real-time clock signal for a period of time without interrupting the processor clock signal.

7. The method of claim 6, wherein the act of suspending the generation of the real-time clock signal is performed in response to a signal controlled by the embedded software application being executed by the embedded processor.

8. The method of claim 6, further comprising restarting the generation of the real-time clock signal without interrupting the processor clock signal, the act of restarting the real-time clock causing the triggering to be continued.

9. The method of claim 8, wherein the act of restarting the generation of the real-time clock signal is performed in response to a signal controlled by the embedded software application being executed by the embedded processor.

10. The method of claim 1, wherein the embedded processor is a simulated embedded processor and the processor clock signal is a simulated processor clock signal, the simulated embedded processor and the simulated processor clock being simulated by software running on a computer workstation.

11. The method of claim 10, wherein the simulated embedded processor and the simulated processor clock signal are simulated using one of an instruction set simulator or an RTOS simulator.

12. The method of claim 1, wherein the embedded processor is part of an embedded system, and wherein the real-time clock signal is generated in part by a clock generator circuit located on the embedded system.

13. The method of claim 1, further comprising measuring execution times of software executed on the embedded processor using a system profiler.

14. The method of claim 1, wherein the embedded software application is a first embedded software application, the embedded processor is a first embedded processor, the RTOS is a first RTOS, and the processor clock signal is a first processor clock signal, the method further comprising:

triggering tasks defined by a second embedded software application with the real-time clock signal, the second embedded software application being executed by a second embedded processor with a second RTOS,

wherein the real-time clock signal is controllable independent of a second processor clock signal driving the second embedded processor such that the real-time clock has a different time base than the second processor clock signal.

15. One or more tangible computer-readable media storing computer-executable instructions for causing a computer to perform the method of claim 1.

16. A method, comprising:

modifying a real-time operating system (“

RTOS”

) for a processor of an embedded system so that a source of a real-time clock signal used by the RTOS to trigger execution of a task is decoupled from a source of a processor clock signal that clocks the processor; and

storing the modified RTOS on one or more computer-readable media.

17. The method of claim 16, wherein the act of modifying comprises altering or adding one or more lines of source code to the source code of the RTOS.

18. The method of claim 16, wherein the act of modifying comprises modifying the RTOS so that a pathway on which the real-time clock signal is communicated is one or more of a local area network (“

LAN”

) channel, universal serial bus (“

USB”

) channel, serial peripheral interface (“

SPI”

) channel, joint test action group (“

JTAG”

) channel, FlexRay channel, local interconnect network (“

LIN”

) channel, controller area network (“

CAN”

) channel, or inter-process communication (“

IPC”

) channel of the embedded system.

19. The method of claim 16, wherein the modified RTOS is stored in memory of the embedded system or in memory of the host computer.

20. The method of claim 16, wherein the RTOS is modified so that the source of the real-time clock signal is software running on a computer workstation, software running on another external embedded system, software that is running as a task within the embedded processor, or a clock generator circuit located on the embedded system.

21. The method of claim 20, wherein the source of the real-time clock signal is software running on a computer workstation, and wherein the software running on the computer workstation is an application running within a debugger or simulator.

22. One or more tangible computer-readable media storing computer-executable instructions for causing a computer to perform the method of claim 16.

23. A method, comprising:

generating a series of real-time event signals; and

triggering tasks defined by an embedded software application with the real-time event signals,

wherein the embedded software application is executed by an embedded processor with a real-time operating system (“

RTOS”

), and

wherein the real-time event signals are controllable independent of processor clock signals driving the embedded processor such that the real-time event signals have a different time base than the processor clock signals.

24. The method of claim 23, wherein the real-time event signals are generated by software running on a computer workstation.

25. The method of claim 24, wherein the software running on the computer workstation is running within a debugger or simulator.

26. The method of claim 23, wherein the real-time event signals are generated by software running on another external embedded system.

27. The method of claim 23, wherein the real-time event signals are generated by software that is running as a task within the embedded processor.

28. The method of claim 23, wherein the real-time event signals indicate that data is ready to be loaded from or sent to a peripheral coupled to the embedded processor.

29. The method of claim 28, wherein the peripheral is connected to a sensor or actuator coupled to a plant.

30. The method of claim 23, further comprising:

generating a real-time clock signal; and

triggering at least one other task defined by the embedded software application with the real-time clock signal,

wherein the real-time clock signal is controllable independent of both the processor clock signals and the real-time event signals such that the real-time clock signal has a different time base than the processor clock signals and the real-time event signals.

31. The method of claim 23, further comprising:

generating a real-time clock signal; and

triggering at least one other task defined by the embedded software application with the real-time clock signal,

wherein the real-time clock signal is controllable independent of the processor clock signals such that the real-time clock signal has a different time base than the processor clock signals, and wherein the real-time event signals are dependent on the real-time clock and have a same time base.

32. The method of claim 23, further comprising suspending the generation of the series of real-time event signals for a period of time without interrupting the processor clock signals.

33. The method of claim 32, wherein the act of suspending the generation of the real-time event signals is performed in response to a signal controlled by the embedded software application being executed by the embedded processor.

34. The method of claim 32, further comprising restarting the generation of the series of real-time event signals without interrupting the processor clock signals, the act of restarting causing the triggering to be continued.

35. The method of claim 34, wherein the act of restarting the real-time event signals is performed in response to a signal controlled by the embedded software application being executed by the embedded processor.

36. The method of claim 23, wherein the embedded processor is a simulated embedded processor and the processor clock signals are simulated processor clock signals, the simulated embedded processor and the simulated processor clock signals being simulated by software running on a computer workstation.

37. The method of claim 36, wherein the simulated embedded processor and the simulated processor clock signals are simulated using one of an instruction set simulator or an RTOS simulator.

38. The method of claim 23, wherein the embedded processor is part of an embedded system, and wherein the real-time event signals are generated by a circuit located on the embedded system.

39. The method of claim 23, further comprising measuring execution times of software executed on the embedded processor using a system profiler.

40. The method of claim 23, wherein the embedded software application is a first embedded software application, the embedded processor is a first embedded processor, the RTOS is a first RTOS, and the processor clock signals are first processor clock signals, the method further comprising:

triggering tasks defined by a second embedded software application with the real-time event signals, the second embedded software application being executed by a second embedded processor with a second RTOS,

wherein the real-time event signals are controllable independent of second processor clock signals that drive the second embedded processor such that the real-time event signals have a different time base than the second processor clock signals.

41. One or more tangible computer-readable media storing computer-executable instructions for causing a computer to perform the method of claim 23.

42. A method, comprising:

modifying a real-time operating system (“

RTOS”

) of a processor in an embedded system so that a source of a real-time event signal used to trigger execution of a task is decoupled from a source of a processor clock signal that clocks the processor; and

storing the modified RTOS on one or more computer-readable media.

43. The method of claim 42, wherein the act of modifying comprises altering or adding one or more lines of source code to the source code of the RTOS.

44. The method of claim 42, wherein the act of modifying comprises modifying the RTOS so that a pathway communicating the real-time event signal is one or more of a local area network (“

LAN”

) channel, universal serial bus (“

USB”

) channel, serial peripheral interface (“

SPI”

) channel, or joint test action group (“

JTAG”

) channel, FlexRay channel, local interconnect network (“

LIN”

) channel, controller area network (“

CAN”

) channel, or inter-process communication (“

IPC”

) channel of the embedded system.

45. The method of claim 42, wherein the modified RTOS is stored in memory of the embedded system or in memory of the host computer.

46. The method of claim 42, further comprising modifying the RTOS so that a real-time clock signal used by the RTOS is also decoupled from the source of the processor clock signal that clocks the processor.

47. The method of claim 42, wherein the RTOS is modified so that the source of the real-time event signal is software running on a computer workstation, software running on another external embedded system, software that is running as a task within the embedded processor, or a clock generator circuit located on the embedded system.

48. The method of claim 42, wherein the source of the real-time event signal is software running on a computer workstation, and wherein the software running on the computer workstation is running within a debugger or simulator.

49. One or more tangible computer-readable media storing computer-executable instructions for causing a computer to perform the method of claim 42.

50. A system, comprising:

a host computer configured to execute software that generates a first signal; and

an embedded system coupled to the host computer and having an embedded processor,

the embedded processor being configured to run a real-time operating system (“

RTOS”

) that executes tasks of a software application based on receipt of the first signal from the software running on the host computer,

the embedded processor being configured to execute individual instructions of the tasks based on receipt of a second signal, the first signal being controllable independent of the second signal such that the first and second signals have a different time base.

51. The system of claim 50, wherein the first signal is the real-time clock signal.

52. The system of claim 50, wherein the first signal is a real-time event signal that is not the real-time clock signal.

53. The system of claim 50, wherein the first signal is communicated through one of a local area network (“

LAN”

) channel, universal serial bus (“

USB”

) channel, serial peripheral interface (“

SPI”

) channel, joint test action group (“

JTAG”

) channel, FlexRay channel, local interconnect network (“

LIN”

) channel, controller area network (“

CAN”

) channel, or inter-process communication (“

IPC”

) channel of the embedded system.

54. The system of claim 50, wherein the software executing on the host computer is capable of suspending the first signal while the second signal continues uninterrupted.

55. The system of claim 50, further comprising one or more additional embedded systems coupled to the host computer, each having respective embedded processors running respective RTOSes that are configured to execute tasks of respective software applications based on receipt of the first signal from software running on the host computer, and each being configured to execute individual instructions of the tasks based on receipt of other respective signals that are controllable independent of the first signal in a manner that allows the first signal and the other respective signals to have a different time base.

56. The system of claim 50, wherein the host computer is further configured to execute a simulator or debugger, and wherein the software that generates the first signal is running within the simulator or the debugger.