Memory Card Identification via Command Pin Response
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Solution Overview
Problem
Existing memory card identification methods, such as those for MMC and SD cards, are slow and inefficient due to the need for multiple commands to determine card type.
Innovation Solution
A method that sends an initialization command specific to each type of memory card protocol, detects responses on the command pin, and initializes the card accordingly, using a shared reset command to enter an idle state and power on the DAT3 pin for SD cards, thereby simplifying the identification process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple commands (CMD8 and ACMD41) are used to identify SD card, then identification accuracy is improved, but identification speed deteriorates
Solution Approach 1:
The patent applies preliminary action by sending the CMD0 reset command before identification to ensure the card is in a known idle state. This prepares the card for subsequent identification commands, ensuring accurate response detection while maintaining efficient identification flow.
Solution Approach 2:
The patent uses feedback by detecting the response status of the command pin to determine card type. The system sends initialization commands and observes whether the card responds, using this feedback information to accurately identify card type without requiring multiple trial commands.
2Reliability
If two-step identification process is used for SD card, then identification reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by using a single identification approach that works for both MMC cards and SD cards. The system sends the MMC initialization command to both card types and uses the response status to differentiate, eliminating the need for separate multi-step identification processes for each card type.
Solution Approach 2:
Instead of sending multiple specific commands to identify card type, the patent inverts the approach by sending a single command and using the absence or presence of response to identify card type. This simplifies the identification logic while maintaining reliability.
3Measurement precision
If CMD8 and ACMD41 commands are sent sequentially, then SD card identification accuracy is improved, but time consumption increases
Solution Approach 1:
The patent applies preliminary action by first sending the CMD0 reset command to ensure the card is in a known state before identification. This preparation step ensures that subsequent identification commands elicit accurate responses, reducing the need for repeated or sequential commands.
Solution Approach 2:
The patent applies skipping by eliminating unnecessary intermediate identification steps. Instead of sequentially sending multiple identification commands, the system sends a single initialization command and directly determines card type based on response status, rushing through the identification process efficiently.
Data Source
AI summary
A memory card identification method and a mobile device are provided. The memory card identification method includes: sending an initialization command of a first-type memory card communications protocol to a to-be-identified memory card; detecting whether there is a response in a command pin of the memory card; and identifying the memory card as a first-type memory card or a second-type memory card based on a response status of the command pin.