Backup method of microcomputer used in case of stoppage of operation, backup unit of microcomputer, and control unit for controlling power window for automobile use
AssigneeYazaki Corporation
InventorYoshihiro Kawamura
Life of this patent
Estimating the term…
Abstract
There is provided an external watchdog timer 30 for detecting a temporary runaway of the microcomputer body 20 and resetting it according to a pulse output of the microcomputer body 20. Further, an internal watchdog timer 70 operated independently from a control section of CPU of the microcomputer body 20 is incorporated as a program. When a pulse signal is not outputted from the microcomputer body 20 exceeding a predetermined period of time, the external watchdog timer 30 is disabled, and impedance of the output terminal 32 is made high and the backup circuit 60 is set in an operating condition, so that the windowpane can be opened and closed by a manual operation switch 11.
Claims14
A backup method of a microcomputer used in the case of stoppage of operation comprising:
- operating a backup system conducting control to be conducted by the microcomputer when a pulse signal outputted from the microcomputer is stopped for a period of time exceeding a predetermined period of time;
- and
- setting an output impedance of a monitor circuit to an increased level when the pulse signal is stopped for the period exceeding the predetermined period of time, and operating the backup system conducting control in response to the increased level output impedance.
A backup method of a microcomputer used in the case of stoppage of operation in which the microcomputer is periodically reset when a frequency of a pulse signal outputted from the microcomputer becomes out of a predetermined range, said backup method comprising:
- operating a backup system conducting control to be conducted by the microcomputer when the pulse signal is stopped for a period of time exceeding a predetermined period of time;
- and
- setting an output impedance of a monitor circuit to an increased level when the pulse signal is stopped for the period exceeding the predetermined period of time, and operating the backup control conducting control in response to the increased level output impedance.
A backup unit of a microcomputer executing a predetermined operation, said microcomputer outputting a pulse signal having a predetermined frequency when said microcomputer properly functions, said backup unit comprising:
- a backup system for executing said predetermined operation in place of said microcomputer;
- an external microcomputer monitor, arranged outside the microcomputer, being externally controllable to be set into an enabled state and a disabled state, monitoring the frequency, and resetting the microcomputer periodically when the frequency of the pulse signal becomes out of a predetermined frequency range;
- and
- an internal microcomputer monitor incorporated into the microcomputer as a program, monitoring said pulse signal, outputting a signal to set said external microcomputer monitor into said disabled state when no pulse signal is outputted for a predetermined time period, and driving said backup system continuously to execute said predetermined operation while said disabled state is set for the external microcomputer monitor.
A power window control unit for automobile comprising:
- a microcomputer executing an operation of pulling up or pulling down a windowpane according to a state of operation of an operation switch, and outputting a pulse signal having a predetermined frequency simultaneously with the start of operation;
- a backup system for executing said operation in place of said microcomputer;
- an external microcomputer monitor, arranged outside said microcomputer, being externally controllable to be set into an enabled state and a disabled state, monitoring the frequency, and resetting said microcomputer periodically when the frequency of the pulse signal becomes out of a predetermined frequency range;
- an internal microcomputer monitor, incorporated into said microcomputer body as a program, monitoring said pulse signal, outputting a signal to said external microcomputer monitor into said disabled state when no pulse signal is not outputted for a predetermined time period, and driving said backup system continuously to execute said predetermined operation while said disabled state is set for said external microcomputer monitor.
Dependencies are inferred from the claim text.