On-chip clock frequency automatic calibration method and related products

Abstract

The embodiment of the present application provides a method for automatic calibration of clock frequency in a chip and related products. The method for automatic calibration of clock frequency in a chip includes: ref The reference level of a period; the calibration module uses the current clock of the oscillator to count the reference level within the width of N o cycles; if the number of theoretical cycles N os with N o The absolute value of the difference is greater than the set error DN, the calibration module adjusts the frequency control parameter through the parameter adjustment module, and the frequency control parameter is used to change the current frequency of the oscillator; N os Based on the reference frequency of the reference clock, the target frequency of the oscillator and the N ref OK; if N os with N o The absolute value of the difference is smaller than the set error DN, and the calibration module determines that the oscillator is calibrated successfully. The embodiment of the present application can shorten the calibration time of the clock frequency in the chip.

Description

technical field [0001] The present application relates to the field of chip technology, in particular to a method for automatically calibrating clock frequency in a chip and related products. Background technique [0002] As the unified baton of the sequential circuit, the clock is an indispensable part of the chip. There are generally two methods for chip clock source design. One is to hang a quartz crystal oscillator outside the chip, and provide a clock source to the chip through chip pin input. The advantage is that the clock frequency is accurate, but the cost is high. The other is to design an oscillator circuit inside the chip to generate a clock. The advantage is high integration and low cost. The disadvantage is that the oscillator cycle will change with process deviation or voltage temperature changes, resulting in relatively large individual differences in clock frequency on multiple chips. Big. Therefore, it is particularly important to calibrate the internal ...

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Problems solved by technology

[0005] 1. When the frequency of the internal oscillator is high, due to the speed limit of the chip pins, the higher frequency clock signal cannot be directly output to the outside of the chip, and it needs to be divided to a lower frequency before releasing

[0006] 2. When measuring a low-frequency clock outside the chip, due to the long cycle of the low-frequency clock, it takes a long time to measure one cycle. For the accuracy of the measurement, it is often necessary to measure multiple low-frequency clock cycles and then take the average value, which significantly increases the test time. Time and chip test cost

[0007] 3. The results of external measurement and calculation of the chip need to be fed back to the inside of the chip through a dedicated communication interface, which makes the peripheral test circuit of the chip complicated.

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