MCU chip frequency division clock correcting device and method

Abstract

The invention discloses an MCU chip frequency division clock correcting device and method. The device comprises a clock module, a clock frequency division circuit, a correcting register, a correcting interface, a storage device and a correcting device body, wherein the clock module, the clock frequency division circuit, the correcting register, the correcting interface and the storage device are arranged in a chip, and the correcting device body is arranged outside the chip. When a clock is corrected, the external correcting device body writes a correcting value into the correcting register through the correcting interface, the clock module adjusts the clock according to the correcting value, the clock is output through the clock frequency division circuit, the external correcting device body adjusts the correcting value according to the clock output until the correcting value with the minimum clock offset is found, the offset value with the actual frequency is worked out, and the correcting value and the clock offset are written into the chip internal storage device. According to the MCU chip frequency division clock correcting device and method, the offset value of a clock crystal oscillator is used for improving the clock accuracy, and the clock accuracy can be greatly improved on the basis of the accuracy of an existing clock oscillator. The accuracy limitation brought by the practice that a fixed correcting value is written in by an external device can be broken through, circuit upgrading does not need to be conducted on the chip, and an external crystal oscillator and an external IO are omitted.

Description

technical field [0001] The invention relates to a clock correction method, in particular to a clock correction device and method for an MCU chip. Background technique [0002] Nowadays, the clock correction function is usually used in chips, especially in the design of MCU. However, due to cost constraints and process technology constraints, the current internal clock can only achieve an accuracy of 0.5% to 2% after correction. Such a clock accuracy level For systems that require asynchronous communication or require high clock accuracy, it is often not enough. It needs to be solved by an external crystal oscillator with more accurate accuracy, and the use of an external crystal oscillator will increase the hardware cost, and the external crystal oscillator needs to add new IO, especially for design Adding new IOs to a system with a smaller size will lead to an increase in the entire hardware area, making the solution unrealizable. [0003] Patent application 2004100864081 ...

AI Technical Summary

Problems solved by technology

However, it is difficult to achieve device matching in such a wide range, and it is necessary to add more additional correction circuits to improve device matching

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