WM710xx – Secure F-RAM with Gen-2 RFID

Rev. 1.4

May 2011

Page 7 of 24

00110

00000000

0

0

1

DEFAULT

Numbering System Identifier

NSI Type

Extended Protocol Control

User Memory identifier

EPC Identifier Word Length

LEN

NSI

XPC NT

UMI

15

11

9

10

8

7

0

bit

PROTOCOL CONTROL WORD

Figure 4. EPC Protocol Control Word

The five most significant bits of the PC indicates the size of the EPC identifier in words – for a 96-bit (6-word)

EPC identifier, the PC should be programmed to 0b0011_0xxx_xxxx_xxxx. The LEN parameter of the PC

word may not be greater than 0b00110 – a LEN parameter of 0b00000 has an EPC identifier length of zero

words resulting in only the PC and CRC words when WM710xx is acknowledged.

The UMI bit (User

Memory Identifier) is asserted to a logic one by WM710xx and mapped to bit 10 of the PC word. In the event

the host writes a logic zero to the UMI bit, the memory location will be written with a logic zero, however the

backscattered EPC identifier will assert the UMI bit to a logic one which is also used in the calculation of the

CRC. WM710xx does not support extended protocol control and should be written with a logic zero. PC word

bits 8 down to 0 of the PC word are factory-initialized to zero. The WM710xx is shipped from the factory with

the EPC memory bank unlocked.

TID Memory Bank:

The TID memory bank consists of 4 words (64 bits), and is defined as shown in Table 2. The TID memory

bank is permanently locked at the factory and obeys the ISO/IEC 15963 numbering convention.

Table 2: TID memory Bank Fields

Class Identifier

MDID[11:4]

MDID[3:0]

TMN[11:0]

ID[31:16]

ID[15:0]

0

7

8

15

16

20

31

32

47

48

63

19

Figure 5. TID Memory Bank Fields

Bit Field

Value

(hex)

Description

E2

ISO/IEC 15963 class-identifier

016

Mask-Designer Identifier (MDID)

– Ramtron International

216

Tag model number

32-bit unique identifier