Total Memory
The complete memory capacity of an NFC chip, including user-accessible memory, manufacturer configuration bytes, UID storage, lock bits, and any reserved areas. Always larger than user memory.
Total Memory
Total memoryTotal memoryComplete chip memory including configuration, UID, and reserved areasView full → refers to the complete storage capacity of an NFC chip, encompassing all addressable bytes including user memory, manufacturer configuration areas, the UID storage, lock bits, OTP bytes, the capability container, and any reserved regions. Understanding total memory versus user memoryuser memoryTag memory portion available for user data storageView full → is essential for correct chip selection — the headline memory capacity on a datasheet is always total memory, not the space available for application data.
Memory Layout (Type 2 Tags)
For NFC ForumNFC ForumIndustry body developing NFC standards, specifications, and certifications since 2004View full → Type 2 tags (the NTAG and MIFARE Ultralight families), memory is organized into 4-byte pages:
| Page Range | Contents | Access |
|---|---|---|
| Page 0-1 | UID (7 bytes) + internal bytes | Read-only (factory set) |
| Page 2 | Lock bitsLock bitsControl bits making memory blocks permanently read-onlyView full → (static) + internal | Read-only once set |
| Page 3 | Capability container (CC) | Configurable |
| Page 4 to N | User memory (NDEF data) | Read/write |
| Page N+1 | Dynamic lock bits | Configurable |
| Last pages | Configuration pages (AUTH0, PWD, PACK) | Password-protected |
For an NTAG 216, total memory is 924 bytes (231 pages of 4 bytes). Of these, pages 0-3 (16 bytes) hold the UID and CC, pages 4-225 (888 bytes) are user memory, and pages 226-230 (20 bytes) hold dynamic lock bits and configuration.
Memory Layout (Type 4 Tags)
Type 4 tags like MIFARE DESFire EV3 use a file-based memory system rather than flat page addressing. The chip's total memory (2 KB, 4 KB, or 8 KB) is partitioned into applications and files, each with individual access control settings. The overhead includes the PICC master key, application keys, file headers, and directory structures.
Chip Selection by Memory
Choosing the right chip requires matching application payload requirements to available user memory, not total memory:
- Simple URL redirect (20-50 bytes): NTAG 213 (144 bytes user) is sufficient.
- vCard or multi-record NDEF (200-500 bytes): NTAG 215 (504 bytes user) or NTAG 216 (888 bytes user).
- Structured application data with security: MIFARE DESFire EV3 (2-8 KB total) with file-level AES encryption.
- Large data with long-range reading: ICODE SLIX2 (2560 bits) or ST25DV (up to 64 Kbit) for NFC-V applications.
Related Terms
Related Guides
Часто задаваемые вопросы
The NFC glossary is a comprehensive reference of technical terms, acronyms, and concepts used in Near Field Communication technology. It is designed for developers, product managers, and engineers who work with NFC and need clear definitions of terms like NDEF, APDU, anti-collision, and ISO 14443.
Each glossary term is cross-referenced with related NFC chips, standards, and other terms. For example, the term 'AES-128' links to chips that support AES encryption (NTAG 424 DNA, DESFire EV2/EV3), and the term 'ISO 14443' links to all chips compliant with that standard.
Yes. NFCFYI provides glossary definitions in 15 languages including English, Korean, Japanese, Chinese, Spanish, Portuguese, Hindi, Arabic, French, Russian, German, Turkish, Vietnamese, Indonesian, and Thai. Use the language selector in the header to switch languages.