Bidirectional Stylus-Sensor Controller Communication Protocol
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Solution Overview
Problem
Existing stylus systems face delays in establishing communication due to the inability to quickly ascertain the capability information of active styluses entering the sensing zone, leading to slow response times and delayed data transmission.
Innovation Solution
A universal stylus-sensor controller interface that supports different active styluses with varying capabilities, using a bidirectional communication protocol with hash values (Hash#1 and Hash#2) to expedite pairing and data transmission by determining downlink time slot allocations based on stylus capability information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the sensor controller transmits the complete capability information of an active stylus every time it enters the sensing zone, then the stylus capability information is fully communicated, but the communication time slots are excessively consumed and response time is delayed
Solution Approach 1:
The patent extracts only the essential capability information (hash value) from the complete capability data set and transmits it to the sensor controller. This extracted hash value serves as a compact representation that enables the controller to identify and retrieve the full capability information from its memory, thereby reducing transmission time while maintaining information completeness.
Solution Approach 2:
The sensor controller pre-stores the complete capability information of various stylus types in its memory before the stylus actually enters the sensing zone. When a stylus enters, the controller only needs to retrieve the pre-stored information based on the transmitted hash value, eliminating the need for lengthy real-time data transmission and enabling rapid response.
2Device complexity
If a rigid data format is used for stylus-to-controller communication, then the communication protocol is simple and stable, but it cannot support different and expanding variations of stylus capabilities and functions
Solution Approach 1:
The patent implements a universal communication protocol where the sensor controller maintains a database of capability information for multiple stylus types. The single hash value transmission format serves multiple functions: it identifies the stylus type, retrieves the appropriate capability set, and enables support for various stylus capabilities (pressure sensitivity, orientation detection, barrel buttons) through a unified interface.
Solution Approach 2:
The system uses hash values as parameter identifiers that can represent different capability configurations. By changing the hash value parameter, the system can adapt to different stylus types and their specific capabilities without altering the fundamental communication protocol structure, thus maintaining simplicity while achieving versatility.
Data Source
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AI summary
A method is provided for communication between a sensor controller and a host processor, wherein the sensor controller is coupled to a sensor configured to interact with an active stylus. The sensor controller is supportive of a default descriptor of a defined set of stylus attributes and transmits the default descriptor to the host processor. The sensor controller, when coupled with a first stylus capable of reporting on a first subset of the defined set of stylus attributes, transmits to the host processor a first stylus report that has fields of the first subset filled with values reported from the first stylus. The sensor controller, when coupled with a second stylus capable of reporting on a second subset of the defined set of stylus attributes, transmits to the host processor a second stylus report that has fields of the second subset filled with values reported from the second stylus