MCU internal clock calibration system and method and PCB

Abstract

The invention relates to an MCU internal lock calibration system and method and a PCB. The system and method are used for acquiring the actual count value of a second timer to be calibrated in an MCB to calibrate the timing time of the second timer. The method comprises the steps that reference clock square waves are loaded to one input / output interface of the MCU, a first timer of the MCU is used for counting, and counting values in one period of the reference clock square waves of the first timer are acquired; the actual counting values of the second timer are acquired according to the counting values in one period of the reference clock square waves of the first timer; the actual counting values of the second timer are stored to allow the second timer to conduct timing according to the actual counting values. The MCU internal lock calibration system and method and the PCB are low in cost and small in probability of failure.

Description

technical field [0001] The present invention relates to a clock calibration system, in particular to an MCU internal clock calibration system [0002] And method and printed circuit board with the system. Background technique [0003] At present, the internal RC oscillation design scheme of the MCU (Micro Control Unit, micro control unit) is usually used to provide the internal clock for the MCU. Due to the error in the internal RC oscillation of the MCU, the clock accuracy is low. Moreover, when the MCU is applied to a PCB (Printed Circuit Board, printed circuit board), the drift of the noise frequency will affect the accuracy of the internal RC oscillator clock again due to the influence of the parasitic capacitance of the external device. In this way, the demand for precise timing cannot be met. If an external ceramic oscillator or crystal oscillator is added, although the clock accuracy can be improved, the design cost is high. At the same time, each additional componen...

AI Technical Summary

Problems solved by technology

[0003] At present, the internal RC oscillation design of the MCU (Micro Control Unit, micro control unit) is usually used to provide the internal clock for the MCU. Due to the error in the internal RC oscillation of the MCU, the clock accuracy is low

Moreover, when the MCU is applied to the PCB (Printed Circuit Board, printed circuit board), the drift of the noise frequency will affect the accuracy of the internal RC oscillator clock due to the influence of the parasitic capacitance of the external device, etc.

In this way, the demand for precise timing cannot be met. If an external ceramic oscillator or crystal oscillator is added, although the clock accuracy can be improved, the design cost is relatively high. At the same time, each additional component also increases a point of failure.

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