Card Device Interface Detection via Legacy Pin Signatures
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Solution Overview
Problem
It is challenging for host devices to identify newly introduced interfaces and protocols in card devices, making it difficult to determine the appropriate interface connection and protocol selection for data transmission.
Innovation Solution
The solution involves a method where the host device uses a legacy interface to issue a command to the card device to identify the presence of new interfaces, such as PCIe, and then initializes the appropriate interface based on the response, allowing for the selection of the correct protocol stack and voltage settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a card device introduces new interfaces (PCIe, USB) alongside legacy interfaces, then the data transmission speed and capability are improved, but the difficulty for host devices to identify and select the appropriate interface increases
Solution Approach 1:
The card device performs preliminary actions by setting specific electrical characteristics (impedance values, voltage levels) on the legacy interface pins before the host device attempts communication. These pre-configured electrical signatures serve as identification markers that allow the host to detect the presence of new interfaces through the legacy interface without requiring direct contact with the new interface pins.
Solution Approach 2:
The legacy interface serves as an intermediary channel that carries information about the new interfaces. By encoding interface presence information through electrical characteristics on the legacy interface, the system enables indirect detection and selection of appropriate interfaces without requiring the host to directly probe or identify physical connections to multiple interface types.
2Adaptability or versatility
If multiple interface types are supported in a card device, then the adaptability and versatility are improved, but the device complexity increases
Solution Approach 1:
The legacy interface is designed to perform multiple functions: it serves both as a communication channel for legacy protocols and as an identification channel for detecting new interfaces. By encoding interface presence information through electrical characteristics on the same physical pins used for legacy communication, the system eliminates the need for separate detection mechanisms for each interface type.
Solution Approach 2:
The card device automatically configures and announces its interface capabilities through pre-set electrical characteristics on the legacy interface. This self-service approach allows the host device to autonomously identify the appropriate interface without requiring complex negotiation protocols or manual configuration, thereby reducing overall system complexity despite supporting multiple interface types.
3Ease of operation
If the host device uses legacy interface to detect new interfaces, then the ease of operation is improved, but the loss of information about the new interface capabilities occurs
Solution Approach 1:
The system uses variations in electrical parameters (impedance values, voltage levels, signal timing) on the legacy interface to encode information about new interface capabilities. By mapping specific parameter combinations to particular interface types or capability sets, the system enables rich information transmission through the legacy interface without requiring direct physical connection to the new interfaces.
Data Source
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AI summary
A card device according to an aspect of the present disclosure includes: a first interface that connects the card device with a host device; and a notification unit that notifies, through the first interface, the host device of whether or not the card device includes a second interface different from the first interface.