Microprocessor auxiliary with combined pin for reset output and pushbutton input
First Claim
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1. An integrated circuit, for performing power management functions, comprising:
- a voltage comparison circuit, connected to monitor the voltage of an external power supply node with reference to a reference-voltage source;
a watchdog timer circuit, connected to detect inactivity of more than a minimum duration on a predetermined input node;
reset control logic, connected to reset nodes;
interrupt generation logic, connected to an interrupt node;
and wherein said reset nodes include both an active-high reset node and an active-low reset node;
and further comprising a debounce circuit connected to said active-low reset node;
wherein when said watchdog timer circuit detects inactivity of more than a minimum duration said reset control logic generates a low pulse at said active-low reset node, and when said debounce circuit detects a low signal at said active-low reset node not generated by said reset control logic, said reset control logic generates a low pulse at said active-low reset node.
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Abstract
A system which includes not only a microprocessor (or microcontroller), but also an auxiliary chip which monitors the system power supply voltage and performs related functions for the microprocessor, and also provides a watchdog function to monitor the microprocessor'"'"'s activity. The auxiliary chip uses only two pins for the three functions of:
active-high-reset out,
active-low-reset out, and
pushbutton reset input.
45 Citations
9 Claims
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1. An integrated circuit, for performing power management functions, comprising:
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a voltage comparison circuit, connected to monitor the voltage of an external power supply node with reference to a reference-voltage source; a watchdog timer circuit, connected to detect inactivity of more than a minimum duration on a predetermined input node; reset control logic, connected to reset nodes; interrupt generation logic, connected to an interrupt node; and wherein said reset nodes include both an active-high reset node and an active-low reset node; and further comprising a debounce circuit connected to said active-low reset node; wherein when said watchdog timer circuit detects inactivity of more than a minimum duration said reset control logic generates a low pulse at said active-low reset node, and when said debounce circuit detects a low signal at said active-low reset node not generated by said reset control logic, said reset control logic generates a low pulse at said active-low reset node. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system, comprising:
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a complex programmable integrated circuit; an auxiliary integrated circuit, which is connected to provide reset and/or interrupt signals to said complex integrated circuit, and which comprises; a voltage comparison circuit, connected to monitor the voltage of an external power supply node with reference to a reference-voltage source; a watchdog timer circuit, connected to detect inactivity of more than a minimum duration on a predetermined input node; reset control logic, connected to reset nodes; interrupt generation logic, connected to an interrupt node; and wherein said reset nodes include both an active-high reset node and an active-low reset node; and further comprising a debounce circuit connected to said active-low reset node; wherein when said watchdog timer circuit detects inactivity of more than a minimum duration said reset control logic generates a low pulse at said active-low reset node, and and at least one manually actuable electrical switch, connected to one of said reset nodes of said auxiliary integrated circuit. - View Dependent Claims (8, 9)
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Specification