| Field | Bits | Size | Description | |-------|------|------|-------------| | | [127:120] | 8 bits | Manufacturer ID—a unique identifier assigned by JEDEC | | Reserved | [119:114] | 6 bits | Reserved for future use | | CBX | [113:112] | 2 bits | Device type (00=Removable, 01=BGA Discrete, 10=POP, 11=Reserved) | | OID | [111:104] | 8 bits | OEM/Application ID—identifies the device OEM or content | | PNM | [103:56] | 48 bits | Product name—a 6-character ASCII string | | PRV | [55:48] | 8 bits | Product revision—encoded as two BCD digits (n.m format) | | PSN | [47:16] | 32 bits | Product serial number—a unique 32-bit unsigned integer | | MDT | [15:8] | 8 bits | Manufacturing date—encoded as month (high nibble) and year (low nibble) | | CRC7 | [7:1] | 7 bits | Checksum of the CID contents | | Reserved | [0:0] | 1 bit | Always 1 |
You do not need to perform manual hex-to-ASCII conversions yourself. Several automated decoding solutions exist:
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Now, let’s decode it using a simple Python snippet or an online tool.
Split into high/low nibbles ( 0 and 1 ). This represents firmware/hardware revision 0.1 . 5. Product Serial Number (PSN) Hex Bytes: 23 45 67 89 emmc cid decoder
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Note that this simplified example assumes the CID bytes are arranged in a specific order; the actual bitfield extraction must account for endianness and bit ordering as specified in the JEDEC standard.
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The Ultimate Guide to eMMC CID Decoder: Decoding Your Flash Storage | Field | Bits | Size | Description
The 128 bits of the CID register are divided into specific device fields defined by the JEDEC eMMC standard (such as JESD84-B51). Field Name Description (Manufacturer ID)
# Byte 9: Product Revision (PRV) - BCD prv = raw_bytes[9] major_rev = (prv >> 4) & 0x0F minor_rev = prv & 0x0F
: Another 8-bit field controlled and allocated by JEDEC, the OID identifies the device OEM and/or the device contents, particularly when used as distribution media on ROM or flash devices.
When you run a raw string through a MultiCID Decoder , it parses the bits into these specific fields: sdmmc eMMC Decode CID properly - NXP Community If you share with third parties, their policies apply
Identifies the OEM or application for which the card was intended. An ASCII string (6 characters) representing the model name. Product Revision The hardware/firmware revision of the product. Serial Number A unique 32-bit binary number. Manufacturing Date Month and year the chip was produced. CRC7 Checksum Used to verify the integrity of the CID data. Available Decoding Tools JEDEC STANDARD - NXP Community
Returns: Dictionary with decoded CID fields """ # Validate input if len(cid_hex) != 32: raise ValueError("CID must be 32 hexadecimal characters (128 bits)")
In the world of embedded storage, eMMC (embedded MultiMediaCard) devices are ubiquitous—they power smartphones, tablets, Chromebooks, automotive infotainment systems, and countless other IoT devices. At the heart of every eMMC device lies the , a 128-bit treasure trove of information that uniquely identifies the storage component. Decoding this register, however, is far from straightforward without the right tools and knowledge. This article provides a comprehensive guide to eMMC CID decoders—what they are, how they work, and how to use them effectively.