Peripheral Interface Chip Bypassing USB Polling for Keyboard Report Rate
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Solution Overview
Problem
The universal serial bus (USB) interface limits the report rate of keyboard devices due to polling, affecting user experience.
Innovation Solution
A peripheral interface chip with a switching circuit, USB host controller, keyboard controller, and microprocessor that determines whether a USB device is a keyboard device and transmits input data through a low pin count (LPC) interface when identified as such, allowing for interrupt requests and increasing the report rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If USB interface polling method is used for keyboard data transmission, then universal compatibility and ease of operation are improved, but report rate is limited and user experience deteriorates
Solution Approach 1:
The patent segments the data transmission path by introducing a switching circuit that separates keyboard device communication from standard USB polling. The switching circuit creates a dedicated transmission path that bypasses the USB host controller's polling mechanism, allowing keyboard data to be transmitted independently through the keyboard controller to the LPC interface, thereby resolving the contradiction between USB compatibility and report rate limitations
Solution Approach 2:
The switching circuit acts as an intermediary component between the USB device and the keyboard controller. It receives device identification from USB devices, determines whether the device is a keyboard, and routes keyboard data through the keyboard controller using interrupt requests rather than USB polling. This intermediary mechanism enables high-speed keyboard communication while maintaining USB interface compatibility for other devices
2Adaptability or versatility
If USB polling mechanism is used, then device compatibility is improved, but data transmission speed and report rate deteriorate
Solution Approach 1:
The system dynamically switches transmission modes based on device identification. When a keyboard device is detected, the switching circuit activates an alternative transmission path using interrupt requests instead of USB polling. This dynamic adaptation allows the system to optimize for speed when keyboards are connected while maintaining compatibility with other USB devices that rely on standard polling mechanisms
Solution Approach 2:
The patent changes the transmission parameter from USB polling-based communication to interrupt request-based communication specifically for keyboard devices. By detecting keyboard devices through device identification and altering the transmission mechanism to use the keyboard controller's interrupt capability, the system achieves higher data transmission speeds and report rates while preserving USB compatibility for non-keyboard devices
Data Source
AI summary
A peripheral interface chip and a data transmission method thereof are provided. The peripheral interface chip includes a switching circuit, a universal serial bus (USB) host controller, a keyboard controller and a microprocessor. The switching circuit receives a device identification transmitted from a USB device, and the device identification is used for determining whether the USB device is a keyboard device. When the USB device is the keyboard device, input data of the USB device is transmitted to a controller hub through a first USB interface, the switching circuit, the USB host controller, the microprocessor, the keyboard controller and a low pin count (LPC) interface.