Methods and devices with sensor time calibration
First Claim
1. A mobile device, comprising:
- a motion sensor having sensor circuitry and a first clock, the motion sensor being configured to generate and store sensor data samples at a predefined output data rate according the first clock; and
a microcontroller, having circuitry, coupled to the motion sensor and being configured to fetch, during a predefined average time span, a sequence of the sensor data samples from the motion sensor and calculate a total number of the sensor data samples fetched;
wherein the microcontroller is further configured to provide a calibrated output data rate based on the total number of sensor data samples fetched and a reference time span, corresponding to a time span during which the sensor data samples were stored at the predefined output data rate, provided by a second clock;
wherein the microcontroller is further configured to determine whether a difference between the predefined output data rate and the calibrated output data rate corresponds to a tolerance threshold such that, in response to the difference corresponding to the tolerance threshold, the microcontroller adjusts time indicators associated with the sensor data samples without adjusting the predefined output data rate of the motion sensor.
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Abstract
Methods and devices with sensor time calibration are provided. A representative device incorporates: a motion sensor having sensor circuitry and a first clock, the motion sensor being configured to generate and store sensor data samples at a predefined output data rate according the first clock; and a microcontroller, having circuitry, coupled to the motion sensor and being configured to fetch, during a predefined average time span, a sequence of the sensor data samples from the motion sensor and calculate a total number of the sensor data samples fetched. The microcontroller is further configured to provide a calibrated output data rate based on the total number of sensor data samples fetched and a reference time span, corresponding to a time span during which the sensor data samples were stored at the predefined output data rate, provided by a second clock.
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Citations
18 Claims
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1. A mobile device, comprising:
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a motion sensor having sensor circuitry and a first clock, the motion sensor being configured to generate and store sensor data samples at a predefined output data rate according the first clock; and a microcontroller, having circuitry, coupled to the motion sensor and being configured to fetch, during a predefined average time span, a sequence of the sensor data samples from the motion sensor and calculate a total number of the sensor data samples fetched; wherein the microcontroller is further configured to provide a calibrated output data rate based on the total number of sensor data samples fetched and a reference time span, corresponding to a time span during which the sensor data samples were stored at the predefined output data rate, provided by a second clock; wherein the microcontroller is further configured to determine whether a difference between the predefined output data rate and the calibrated output data rate corresponds to a tolerance threshold such that, in response to the difference corresponding to the tolerance threshold, the microcontroller adjusts time indicators associated with the sensor data samples without adjusting the predefined output data rate of the motion sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A sensor time calibration method comprising:
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generating motion sensor data samples at a predefined output data rate according a first clock; storing, in a first buffer, the motion sensor data samples at the predefined output data rate; generating a sample count indicating the number of samples stored in the first buffer; providing a flush signal in response to the sample count corresponding to a watermark value; fetching, by a microcontroller configured to selectively operate in a power saving mode and a sample fetch mode, a sequence of the sensor data samples during a predefined average time span, wherein the sensor data samples are fetched in batches from the first buffer in response to receiving the flush signal; calculating a total number of the sensor data samples fetched; and providing a calibrated output data rate based on the total number of sensor data samples fetched and a reference time span, corresponding to a time span during which the sensor data samples were stored at the predefined output data rate, provided by a second clock; wherein the microcontroller is operated in the power saving mode, then, in response to receiving the flush signal, operated in the sample fetch mode such that the microcontroller fetches the sensor data samples in batches from the first buffer. - View Dependent Claims (16, 17, 18)
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Specification