just posted a nice article on how to read the CID (or PSN) from an SD card, or product serial number. This is the checksum of the CID contents computed as described in SD Specification. UPDATE (Feb 16, 2023): We learned the company which manufactures this product now offers the ability to write the CID value as well as write protect the Secure Digital media. The manufacturing date is composed of two hexadecimal digits one is 8 bits representing the years(y) and the other is 4bits representing the month (m).ĬRC7 checksum (7 bits). The Serial Number is 32bits of binary number. The “n” is the most significant nibble and “m” is the least significant nibble As an example, the PRV binary value field for product revision “6.2” will be: 0110 0010b The product revision is composed of two Binary Coded Decimal (BCD) digits, four bits each, representing an ![]() As a CID number is unique for each SD card, it is very often used for software licensing and content protection. CID number is set by the manufacturer and cannot be changed after it is set. The product name is a string, 5-character ASCII string. The C ard ID entification (CID) register is 16 bytes (128 bits) code that contains information that uniquely identifies the SD card. From page 93 of Part 1 Physical Layer Simplified Specification: The Card IDentification (CID) register is 128 bits wide. It is stored in a special register which is accessed using the SENDCID command. Ltd., SanDisk Corporation and Toshiba Corporation. To partially answer my own question, the CID is a unique identifier assigned to the SD card at manufacture time. Note: SD-3C, LLC licenses companies that wish to manufacture and/or sell SD Memory Cards, including but not limited to flash memory, ROM, OTP, RAM, and SDIO Combo Cards SD-3C, LLC is a limited liability company established by Matsushita Electric Industrial Co. This procedure is established to ensure uniqueness of the CID register. The OID number is controlled, defined, and allocated to a SD Memory Card manufacturer by the SD-3C, LLC. Apparently some cheap cards may or may not follow the spec perfectly, and then it appears that 'CMD26' ( ref) is what you need. ![]() Essentially, its PROM - theres no erase functionality. This procedure is established to ensure uniqueness of the CID register.Ī 2-character ASCII string that identifies the card OEM and/or the card contents (when used as a distribution media either on ROM or FLASH cards). The SD card spec defines that the CID can be written exactly once, and that happens when the card is manufactured. The MID number is controlled, defined, and allocated to a SD Memory Card manufacturer by the SD-3C, LLC. The structure of the CID register is defined in the following paragraphs:īinary number of 8-bit that identifies the manufacturer of the card. Every individual Read/Write (RW) card shall have a unique identification number. It contains the card identification information used during the card identification phase. The Card Identification (CID) register is 128 bits wide.
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