ST AN2319 APPLICATION NOTE

AN2319

Application note

Using the 64-bit UID in contactless RFID applications

Introduction

All STMicroelectronics contactless memory products provide a 64-bit unique identifier (UID)
for use with RFID applications. The 64-bit UID is a value written by STMicroelectronics
during the manufacturing process and it is guaranteed unique for each contactless memory.

This UID can be used by the final application system to identify each tag individually and
also, depending on the recognized memory type, to modify memory access models and
maps.

This application note describes how STMicroelectronics handles the 64-bit UID and how
applications can decode its value.

January 2009 Rev 2 1/8

www.st.com

Contents AN2319

Contents

1 UID description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.1 Unique serial number [41:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2 Product code [47:42] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3 Silicon manufacturer code [55:48] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.4 Tag registration category [63:56] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3 Application examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.1 Example 1: high-level mnemonic source code . . . . . . . . . . . . . . . . . . . . . . 5

3.2 Example 2: low-level mnemonic source code . . . . . . . . . . . . . . . . . . . . . . 6

4 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

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AN2319 UID description

1 UID description

The 64-bit UID of STMicroelectronics provides a maximum of 242 (4,398,046,511,104)
unique ID tags per family.

Table 1. 64-bit unique identifier (UID) description

Bits [63:56] [55:48] [47:42] [41:0]

Size (bits) 88642

Val ue

Tag registration

category (0xD0)

Silicon manufacturer

code (0x02)

1.1 Unique serial number [41:0]

These 42 bits are the traceable unique serial number.

1.2 Product code [47:42]

These 6 bits store the STMicroelectronics product code. This code is unique for each tag
family product and that is why it can be used by the contactless system to identify the
product in the reader's antenna field. Once recognized, the contactless system knows the
command set and available memory map. Tab le 2 lists the product codes that identify
current products.

Table 2. ST product code chart

Binary Decimal SR product

00 0010 2 SR176

00 0011 3 SRIX4K

00 0100 4 SRIX512

00 0110 6 SRI512

Product code

Unique serial

number

00 0111 7 SRI4K

00 1100 12 SRT512

1.3 Silicon manufacturer code [55:48]

This bit field identifies the Silicon manufacturer code. Value 0x02 is dedicated for
STMicroelectronics in compliance with ISO 7816-6/AM1 specifications.

1.4 Tag registration category [63:56]

This bit field corresponds to the Registration category for RFID applications. Value 0xD0 is
attributed to ISO14443-B standard devices.

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