Emulator support mode for disabling and reconfiguring timeouts of a watchdog timer
First Claim
1. A watchdog timer having an emulator support mode for disabling watchdog time-outs, comprising:
- a watchdog timer core;
a watchdog timer control register for controlling timing for the watchdog timer core; and
write enable logic for disabling writes to the watchdog timer control register in a normal operational mode subsequent to a write asserting an enable bit of the watchdog timer control register and enabling writes to the watchdog timer control register in the emulator support mode subsequent to a write asserting the enable bit.
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Accused Products
Abstract
A microcontroller-based device according to the present invention provides a watchdog timer having an emulator support mode for disabling and reconfiguring time-outs. When the watchdog timer is placed in the emulator support mode, the watchdog timer is inhibited from counting. In a disclosed embodiment, the watchdog timer is inhibited from counting by deasserting a count enable signal. A watchdog time-out is thus prevented from occurring during the emulator support mode. Also, during the emulator support mode, the watchdog timer control register is writable, allowing the emulator to disable a watchdog timer, enable the timer, or program a new time-out value for the timer. The watchdog timer control register is writable regardless of the state of the enable bit of the timer. Further, in the emulator support mode, a watchdog timer current count becomes readable and writable at a predetermined register address above the watchdog timer control register subsequent to a write of a write key sequence to the watchdog timer control register. By writing and reading the predetermined register address location, the emulator is able to define and monitor a condition as the watchdog timer is approaching its timeout value. By monitoring a condition as the watchdog timer approaches its timeout value, a software debugger may better predict and appreciate the behavior of a microcontroller-based device prior to a watchdog time-out. In a disclosed embodiment, the watchdog timer current count is readable and writable through a watchdog timer count high register and a watchdog timer count low register.
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Citations
23 Claims
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1. A watchdog timer having an emulator support mode for disabling watchdog time-outs, comprising:
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a watchdog timer core; a watchdog timer control register for controlling timing for the watchdog timer core; and write enable logic for disabling writes to the watchdog timer control register in a normal operational mode subsequent to a write asserting an enable bit of the watchdog timer control register and enabling writes to the watchdog timer control register in the emulator support mode subsequent to a write asserting the enable bit. - View Dependent Claims (2, 3, 4)
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5. A watchdog timer having an emulator support for reconfiguring watchdog time-outs, comprising:
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a watchdog timer core; a watchdog timer current counter for indicating a current count of the watchdog timer core; and current count logic for controlling the watchdog timer current counter, the current count logic being non-readable and non-programmable in a normal operational mode and being readable and programmable in an emulator support mode. - View Dependent Claims (6, 7)
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8. A microcontroller having emulation support for disabling watchdog time-outs, comprising:
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a microprocessor core; a watchdog timer, comprising; a watchdog timer control register controlling timing for the watchdog timer; and write enable logic for disabling writes to the watchdog timer control register in a normal operational mode subsequent to a write asserting an enable bit of the watchdog timer control register and enabling writes to the watchdog timer control register subsequent to a write asserting the enable bit in the emulator support mode. - View Dependent Claims (9, 10, 11)
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12. A microcontroller having emulator support for reconfiguring watchdog time-outs, comprising:
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a microprocessor core; a watchdog timer, comprising; a watchdog timer current counter for indicating a current count of the watchdog timer; and current count logic for controlling the watchdog timer current counter, the current count logic being non-readable and non-programmable in a normal operational mode and being readable and programmable in an emulator support mode. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A method of decoupling the timing of a watchdog timer from code execution by an emulator, comprising the steps of:
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detecting an indication to enter an emulator support mode of the watchdog timer; and entering an emulator support mode for inhibiting the watchdog timer from counting. - View Dependent Claims (19, 20)
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21. A method of reconfiguring a watchdog time-out of a watchdog timer, comprising the steps of:
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placing the watchdog timer in an emulator support mode, a current count of the watchdog timer being programmable in the emulator support mode; and programming the current count of the watchdog timer. - View Dependent Claims (22, 23)
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Specification