Gated Input Capture Peripheral for Noise-Resistant Time Measurement
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Solution Overview
Problem
In noisy environments, existing input capture peripheral devices for microcontrollers are prone to false triggering, making precise time measurement challenging due to the inability to effectively filter out random noise events.
Innovation Solution
An improved input capture peripheral device with a gating input that controls activation and a programmable output to gate other peripherals, combined with a charge time measurement unit, allows for precise time measurement by using internal or external signals and comparators to generate gating and event signals, enabling precise timing measurements by masking noise events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an input capture peripheral is used to measure time in noisy environments, then time measurement functionality is provided, but false triggering occurs due to random noise events
Solution Approach 1:
A gating signal is introduced as an intermediary control mechanism between the input capture peripheral and the actual capture operation. The gating signal acts as a mediator that selectively enables or disables the capture function based on environmental conditions, preventing false triggering by noise events while allowing legitimate capture operations to proceed
Solution Approach 2:
The input capture peripheral transitions from a static always-on state to a dynamic state where capture functionality is selectively enabled or disabled based on the gating signal. This dynamic control allows the system to adapt to changing environmental conditions, enabling precise time measurement only when gating conditions are met, thereby eliminating false triggering from noise
2Reliability
If a gating input is added to control capture activation, then false triggering is eliminated, but device complexity increases
Solution Approach 1:
The gating input mechanism is designed to be universally applicable to the input capture peripheral, serving multiple functions: it controls capture activation, filters noise events, and can be integrated with existing microcontroller peripherals. This multi-functionality justifies the added complexity by providing comprehensive control over capture operations across different operating conditions
3Measurement precision
If noise filtering is implemented through gating logic, then measurement accuracy improves, but additional control signals and circuitry are required
Solution Approach 1:
The gating logic is merged with the existing input capture peripheral structure, combining the noise filtering function with the time measurement functionality. The gating signal is integrated into the capture control mechanism, eliminating the need for separate filtering circuitry and reducing overall system complexity while maintaining measurement accuracy
Data Source
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AI summary
A microcontroller has an input capture peripheral, wherein the input capture peripheral is configured to store timer values of an associated timer in a memory and wherein the input capture peripheral has a gating input which controls whether an input capture function is activated.