Touch Sensing Display SPI Architecture for Sub-Millisecond Transfer
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Solution Overview
Problem
Touch sensing display apparatuses face challenges in achieving a touch transfer time of less than 1 msec due to reduced vertical blank periods with increasing frame rates and resolutions, necessitating faster ADC processing and data transfer.
Innovation Solution
A touch sensing display apparatus with a display panel, touch blocks, readout integrated circuits (ROICs), and micro control circuits connected via a serial peripheral interface (SPI), utilizing 16-bit and 32-bit memory systems for efficient data transfer of touch raw data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If frame rate and resolution of display panel are increased, then display quality is improved, but vertical blank period is reduced making touch time less than 1 msec difficult to achieve
Solution Approach 1:
The patent segments the touch data transfer process into multiple parallel channels. Multiple readout ICs are assigned to different touch blocks, and multiple micro control circuits process data from different channels simultaneously. This parallel segmentation allows touch sensing to occur during the reduced vertical blank period by distributing the processing load across multiple independent pathways.
Solution Approach 2:
The patent implements preliminary action by pre-configuring the memory storage systems with appropriate bit-widths (16-bit for ROIC, 32-bit for MCU) and pre-establishing the SPI communication protocols. The memory units are designed with specific capacities to hold touch raw data before processing, allowing data to be ready for immediate transfer when the vertical blank period begins, eliminating any setup or initialization delays during the already-compressed time window.
2Speed
If touch transfer time is reduced to meet 1 msec spec, then touch response speed is improved, but data transfer completeness and accuracy may be compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the SPI data transfer configuration with specific bit-widths (12-bit transfer system) and adjusting the timing parameters to fit within the 1 msec window. The memory storage capacities are specifically designed (16-bit for ROIC, 32-bit for MCU) to accommodate the compressed data transfer timeline while maintaining data integrity through appropriate data width selection and buffer sizing.
3Loss of time
If SPI data transfer is optimized with 12-bit system, then transfer time is reduced, but memory storage capacity requirements change
Solution Approach 1:
The patent applies local quality by assigning different memory storage capacities to different components based on their specific needs. The readout IC is equipped with 16-bit memory units sized appropriately for holding touch raw data from its assigned touch blocks, while the micro control circuit is equipped with larger 32-bit memory units to accommodate data from multiple channels. This localized optimization of memory capacity at each stage minimizes overall transfer time while avoiding excessive memory allocation.
Data Source
AI summary
A touch sensing display apparatus may include touch blocks, touch electrodes in each touch block, a readout integrated circuit (ROIC) for sensing the touch electrodes to obtain touch raw data, and a micro control circuit connected to the ROIC through a serial peripheral interface (SPI). A memory of the ROIC may have a 16-bit row unit storage system. Each of a TX memory and an RX memory of the micro control circuit may have a 32-bit row unit storage system. In a touch period for touch driving, J pieces of SPI data having a 12-bit transfer system corresponding to address and command data for reading the touch raw data may be transferred from the micro control circuit to the ROIC, and K pieces of SPI data having a 12-bit transfer system corresponding to the touch raw data may be transferred from the ROIC to the micro control circuit.