Shared Oscillator I/O Switching in Microcontrollers
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Solution Overview
Problem
Microcontrollers require two pairs of input/output cells for high and low frequency oscillators, limiting design flexibility and increasing resource usage, as users often prefer to use only one oscillator and internal resonators are less precise.
Innovation Solution
A microcontroller with a shared pair of input/output cells connected to both oscillators via a switching circuit, allowing either oscillator to be connected to the same pair of cells, reducing the number of dedicated input/output cells and enhancing design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two separate pairs of input/output cells are allocated for high frequency and low frequency oscillators, then each oscillator can operate independently with dedicated connections, but the number of input/output cells increases and design flexibility is reduced
Solution Approach 1:
The patent combines two separate input/output cell pairs into a single shared pair that can serve both the high frequency oscillator and the low frequency oscillator through a switching circuit. This merging reduces the total number of input/output cells from four to two, directly addressing the contradiction by maintaining oscillator independence through time-multiplexed access while reducing device complexity.
Solution Approach 2:
The patent introduces a dynamic switching mechanism that allows the single input/output cell pair to be dynamically connected to either the high frequency oscillator or the low frequency oscillator as needed. This dynamic allocation enables the system to maintain the functional independence of both oscillators while using fewer physical connections, resolving the contradiction between reliability and device complexity.
2Reliability
If two separate pairs of input/output cells are used for high and low frequency oscillators, then each oscillator has dedicated connections, but design flexibility for electronic card layout is limited
Solution Approach 1:
The patent creates a universal input/output cell pair that can function for both high frequency and low frequency oscillator connections. This multi-functional design allows the same physical cells to serve multiple purposes depending on the operational mode, thereby increasing electronic card design flexibility while maintaining stable oscillator connections through the switching mechanism.
3Device complexity
If internal resonators are used due to reduced input/output cells, then the number of input/output cells is reduced, but measurement precision decreases
Solution Approach 1:
The patent introduces an external resonator as an intermediary component that connects to the shared input/output cell pair. This external resonator provides the precise frequency reference needed for accurate measurements, while the switching circuit acts as a mediator to connect the resonator to the appropriate oscillator. This configuration allows the system to use fewer input/output cells while maintaining high measurement precision through the external resonator.
Data Source
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AI summary
One aspect of the invention relates to a microcontroller comprising: - at least one pair of input/output cells configured to be able to be connected to a first external resonator, - a first oscillator and a second oscillator, and wherein at least one pair, referred to as the shared pair, of said at least one pair of input/output cells is also configured to be able to be connected to a second external resonator, the microcontroller further comprising a switching circuit between said shared pair of input/output cells and the first and second oscillators, the switching circuit being configured to be able to connect either the first oscillator or the second oscillator to the pair of input/output cells.