Pipelined Capacitive Touch Sensing for Latency Reduction
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Solution Overview
Problem
Existing capacitive sensing systems experience increased response times due to processor bottlenecks, as all configurations must be performed by the processor before starting a conversion process, leading to idle time when busy with other tasks.
Innovation Solution
Implementing a pipelined conversion method where the capacitive sensing system configures and reconfigures while converting capacitance, allowing for simultaneous integration and processing across multiple channels, decoupling the processor from scanning and enabling interrupt-driven operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the processor performs all configurations before starting conversion, then the conversion process can be properly initialized, but the system experiences increased response time and idle time when the processor is busy with other tasks
Solution Approach 1:
The patent applies preliminary action by pre-configuring conversion parameters and settings in advance within the capacitive sensing system itself, before the actual conversion process begins. This allows the system to have conversion-ready configurations already in place, eliminating the need for the processor to perform time-consuming setup operations at the moment conversion is needed, thus reducing response time while maintaining reliable initialization.
Solution Approach 2:
The patent segments the configuration and conversion processes by separating them into distinct functional blocks within the capacitive sensing system. The configuration functions are implemented as independent hardware or firmware modules that can operate autonomously from the processor, allowing simultaneous or overlapping execution of configuration and conversion tasks, thereby eliminating idle time when the processor is busy with other operations.
2Ease of operation
If the processor services interrupts and other hardware tasks, then system responsiveness to external events is maintained, but the capacitive sensing system sits idle increasing overall response latency
Solution Approach 1:
The patent implements self-service by enabling the capacitive sensing system to autonomously perform configuration and conversion operations without requiring continuous processor intervention. The system includes dedicated hardware or firmware components that can independently manage sensing element configurations, perform capacitance measurements, and execute conversion processes, allowing the processor to service other hardware tasks while the sensing system continues its operations independently, thus maintaining both system responsiveness and conversion productivity.
3Ease of manufacture
If standard in-line code configuration is used, then the implementation is simple and maintainable, but the system efficiency is reduced due to sequential processing requirements
Solution Approach 1:
The patent introduces an intermediary layer in the form of dedicated configuration registers, control blocks, or firmware interfaces that mediate between the processor and the conversion hardware. This intermediary structure allows the processor to issue simple configuration commands without needing to manage the entire conversion process sequentially, enabling parallel execution of configuration and conversion tasks while maintaining implementation simplicity through standardized interfaces and registers.
Data Source
AI summary
A touch sensing system and methods of operating the same for pipelined conversions are provided. In one embodiment, the method includes: (i) configuring a capacitive sensing system including a plurality of capacitive sensing elements for a first conversion; (ii) sensing capacitance in the capacitive sensing elements, and converting the capacitance sensed in the capacitive sensing elements to a digital, first conversion result; and (iii) while converting the capacitance sensed to the first conversion result, configuring the capacitive sensing system. In another embodiment, the capacitive sensing system includes a plurality of channels, and sensing capacitance and converting the capacitance sensed to the first conversion result includes integrating analog signals from the capacitive sensing elements for one of the plurality of channels while converting the integrated signal for another of the plurality of channels to a digital subconversion result.