Active Pen–Touch Controller Sync for Noise-Resilient Drawing
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Solution Overview
Problem
In two-way communication systems between a pen and a touch controller, the pen may fail to receive an uplink signal due to external noise, leading to synchronization issues that cause breaks in line drawing.
Innovation Solution
The system employs a frame structure with temporally separated pen detection periods, allowing the pen to transmit a reference change signal when synchronization is lost, enabling it to act as the master of synchronization and maintain frame synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pen applies the last acquired frame position to transmit pen signals when uplink signal is not received, then the pen can continue transmitting signals to prevent break in line, but the timing gradually becomes off making it difficult for the touch controller to receive pen signals
Solution Approach 1:
The system dynamically switches between two synchronization modes: normal mode where the touch controller transmits uplink signals for synchronization, and inverted mode where the pen transmits reference change signals to become the synchronization master. This dynamic role reversal allows the pen to maintain timing accuracy when uplink signals are lost, resolving the contradiction between continuous transmission reliability and timing precision.
2Reliability
If the touch controller transmits uplink signals at the beginning of each frame for synchronization, then the pen can acquire frame position and maintain synchronization, but the pen may fail to receive uplink signals due to external noise causing break in line
Solution Approach 1:
The system prepares for potential uplink signal reception failures by enabling the pen to switch to inverted mode and transmit reference change signals. This preemptive mechanism ensures that when external noise blocks uplink signals, the pen can immediately take over synchronization roles, cushioning against the harmful effect of noise without causing line breaks.
3Ease of manufacture
If the pen uses predefined time slots for transmitting pen signals according to protocol, then the communication structure is simple and standardized, but the pen cannot adapt when uplink signals are not received to maintain continuous drawing
Solution Approach 1:
The protocol incorporates a dynamic role reversal mechanism where the pen can switch from being a slave (receiving uplink signals) to being a master (transmitting reference change signals). This dynamic adaptation within the predefined protocol structure allows the pen to maintain continuous drawing operations even when uplink signals are lost, while preserving the simplicity and standardization of the overall communication framework.
Data Source
AI summary
An active pen and a touch controller are configured to use a frame F including a plurality of temporally separated time slots TS0 to TSm to transmit and receive signals with each other. Each of the active pen and the touch controller can transmit and detect a reference signal for synchronizing a frame position, which is a temporal position of the frame F, and upon detecting the reference signal acquires the frame position based on the reference signal and operates according to the acquired frame position. The active pen is configured to transmit, when changing a master of the synchronization, a reference change signal CH indicating that the active pen itself is the master of the synchronization.