EM MICROELECTRONIC EM4223 User Manual

EM MICROELECTRONIC - MARIN SA

EM4223

Read-only UHF Radio Frequency Identification Device

according to ISO IEC 18000-6

Description

The EM4223 chip is used in UHF passive read-only transponder applications. The chip derives its operating power from an RF beam transmitted by the reader, which is received and rectified by the chip. It transmits its factory-programmed code back to the reader by varying the amount of energy that is reflected from the chip antenna circuit (passive backscatter modulation). The air interface communication protocol is implemented according to ISO18000-6 type A. The code structure supports the effort of EPCglobal, Inc. as an industry accepted standard. It additionally incorporates the Fast Counting Supertag™ protocol for applications where the fast counting of large tag populations is required. The chip is frequency agile, and can be used in the range of 800 MHz to 2.5GHz for RF propagating field applications.

Typical Applications

Supply chain management (SCM)

  Tracking and tracing  Asset control  Licensing  Auto-tolling

Key words

ISO 18000-6A

  UHF  EPC™ data structure  Fast Supertag™

Features

Air interface is ISO18000-6 type A compliant

  Supports EAN•UCC and EPC™ data structures as

defined by the Auto-ID center

 Supports Fast Counting Supertag™ mode  128 bit user memory license plate Group select by

means of ‘Application Family Identifier’ (AFI) according to ISO

 Fast reading of user data during arbitration (no need

to first take an inventory)

 Specific command set for supply chain logistics

support.

 Frequency independent: Typically used at 862 - 870

MHz, 902 - 950 MHz and 2.45 GHz

 Low voltage operation - down to 1.0 V  Low power consumption  Cost effective  -40 to +85°C operating temperature range

Benefits

 Numbering scheme according to international

standards

 Operates worldwide according to the local radio

regulation

 Ideal for applications where long range and high-

speed item identification is required

Typical Operating Configuration

Connect pad A+ And V dipole antenna

to a

A+

EM4223

VSS

Chip design is a joint development with RFIP Solutions Ltd

VDD

Fig. 1

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READ-ONLY UHF RADIO FREQUENCY

IDENTIFICATION DEVICE ACCORDING TO

ISO IEC 18000-6.................................................

Description ..................................................................1H1H1

Typical Applications ....................................................2H2H1

Key words ...................................................................3H3H1

Benefits.......................................................................4H4H1

TABLE OF CONTENTS.....................................5H5H2

Absolute Maximum Ratings ........................................6H6H3

Handling Procedures ..................................................7H7H3

Operating Conditions ..................................................8H8H3

Block Diagram.............................................................9H9H3

Electrical Characteristics.............................................10H10H4

Timing Characteristics ................................................11H11H4

1. GENERAL DESCRIPTION.................................12H12H5

2. FUNCTIONAL DESCRIPTION...........................13H13H5

General Command Format .........................................14H14H6

Supported Command set ............................................15H15H6

3. BASIC COMMAND FORMATS..........................16H16H6

Short commands.........................................................17H17H6

Extended commands ..................................................18H18H6

Implied MUTE command (Fast Supertag Mode only) .19H19H7

Command state transitions .......................................20H20H11

0H0H1

EM4223

COMMANDS AND STATES............................ 43H43H23

Commands............................................................... 44H44H23

Tag States................................................................ 45H45H23

Tag state storage ..................................................... 46H46H24

10. COLLISION ARBITRATION............................ 47H47H25

General explanation of the collision arbitration

mechanism...............................................................

FST SYSTEMS ........................................................ 49H49H25

FST MODE OPTIONS.............................................. 50H50H26

Use of the round_size function (ISO & FST modes). 51H51H27

Ordering Information ................................................ 52H52H29

Versions ................................................................... 53H53H29

48H48H25

4. GENERAL REPLY FORMAT...........................21H21H14

5. FORWARD LINK ENCODING - READER TO

TRANSPONDER ..............................................

Carrier modulation pulses .........................................23H23H15

Basic time interval – definition of “Tari” .....................24H24H15

Data coding...............................................................25H25H16

Data Frame format....................................................26H26H16

Data decoding...........................................................27H27H17

Bits and byte ordering ...............................................28H28H17

Reader to Transponder 5 bit CRC (CRC-5) ..............29H29H17

Command Decoder...................................................30H30H17

22H22H15

6. RETURN LINK DATA ENCODING -

TRANSPORTER TO READER ........................

Return link data encoding .........................................32H32H18

Return link preamble.................................................33H33H19

Cyclic Redundancy Check (CRC) .............................34H34H19

31H31H18

7. MEMORY ORGANISATION AND

CONFIGURATION INFORMATION.................

Memory Map.............................................................36H36H19

Unambiguous User Data (UUD) & SUID...................37H37H19

AFI ............................................................................38H38H20

Personality Block ......................................................39H39H20

35H35H19

8. TRANSPONDER SELECTION OPERATION –

INIT_ROUND AND BEGIN_ROUND

COMMANDS.....................................................

INIT_ROUND COMMAND SELECTION OPERATION

..................................................................................

BEGIN_ROUND COMMAND SELECTION

OPERATION .............................................................

40H40H21

41H41H21

42H42H22

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Absolute Maximum Ratings

Parameter Symbol Min Max

-0.3

-50

+3.6

+150 10

Table 1

Supply Voltage V

– VSS (V)

Storage temperature (°C) RMS supply current pad A (mA)

store

Stresses above these listed maximum ratings may cause permanent damages to the device. Exposure beyond specified operating conditions may affect device reliability or cause malfunction.

Handling Procedures

This device has built-in protection against high static voltages or electric fields; however, anti-static precautions must be taken as for any other CMOS component. Unless otherwise specified, proper operation can only occur when all terminal voltages are kept within the voltage range. Unused inputs must always be tied to a defined logic voltage level.

Operating Conditions

Parameter Symbol Min Max Unit

Supply voltage VDD 1.0 3.5 V Operating Temperature TA -40 +85 °C

Block Diagram

Data

ROM 128b

EM4223

Table 2

AFI

ROM 8b

Ant

Limit

LOGIC

PON

OSC

Data

extractor

Fig. 2

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EM4223

Electrical Characteristics

VDD= 2.0V, T

Operating voltage VDD – VSS V Current consumption IS V Power On Reset Rising V Power On Reset Fall V Electrostatic discharge HBM to MIL-STD-

Internal oscillator frequency Input series Impedance @900MHz

Modulation depth decoding

=+25°C, unless otherwise specified

Parameter Symbol Conditions Min. Typ. Max. Unit

3.5 V

ponf

= 1.5 V 2.0 3.9 uA

DD-VSS

1.2 V

ponr

1.0 V

ponf

883 method 3015

VDD and VSS pad A+ pad

1.5

0.5

Fosc Over full temperature range 192 320 448 KHz

Rin C

– VSS < 1V 19

0.620

At typical pulse width 27 % 100 % %

Timing Characteristics

Over full voltage and temperature range, unless otherwise specified

Parameter Symbol Conditions Min. Typ. Max. Unit

Forward Link (Reader to Transponder) Pulse width Tpw 100% modulation depth 6 10 14 uS Pulse interval Data 0 T Pulse interval Data 1 T

Return Link (Transponder to Reader) (note 1) Bit rate accuracy short term (note 2) Bit rate accuracy long term @1.5V

Reply to Receive

turn-around time

Receive to Reply

turn-around time

Tag Command window Tcw Opens at the start of the 3rd bit

Note 1: VDD= 2.0V, TA=+25°C Note 2: V

= 2.0V

average 33 kbps

100% modulation depth 12 20 28 uS

pi0

100% modulation depth 24 40 56 uS

pi1

nominal at 25°C as selected by

factory programmed Personality Bit

kbps

160

During a message transmission +/- 1 %

of nominal 40kb/s +/- 15 %

2 Bit

Depends on Transponders chosen

150 uS

reply slot

clock period after the end of the last bit transmitted by the Transponder to the reader. Closes in the middle of the 5th bit clock period.



Table 3

times

Table 4

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1. GENERAL DESCRIPTION

The EM4223 is a monolithic integrated circuit transponder for use in UHF passive backscatter RFID applications. Operating power for the transponder circuit is derived from the illuminating RF field of an RFID Reader by means of an on-chip virtual battery rectifier circuit. A user specified license plate or tag identifier is factory programmed into the transponder by means of laser trimming. This data is communicated to the reader by means of backscatter modulation of the illuminating RF carrier wave. The EM4223 supports both the ISO18000-6 type A and the Fast Supertag (FST) Protocols. The EM4223 may be configured to wake-up in either of these modes according to user requirements. Once active, the transponder will automatically respond to either protocol (and eventually switch modes) on receipt of the appropriate commands.

2. FUNCTIONAL DESCRIPTION

When a Transponder is placed in the RF energising field of a Reader it powers up. When the power supply has reached the correct operating voltage, the Configuration Register is loaded with the contents of the three preprogrammed personality flags. Depending on the state of these wake-up flags, the Transponder will be placed in either ISO 18000-6 Type A (ISO) or Fast Supertag (FST) mode and in one of three states: READY, ACTIVE or ROUND_STANDBY. After this process is complete the Transponder is able to receive commands and to transmit data to the Reader.

The Transponder is half-duplex and is thus in either receive mode (default) or transmit mode. When not actively transmitting messages to the Reader on the Return Link, the Transponder will wait for the start of a new command, which will be detected as a quiet period of specific duration, followed by a valid Start Of Frame (SOF) symbol (see the quiet period in order to ensure that it does not detect partial transmissions by a reader as a valid command. This can occur if a transponder enters the field of a reader and powers up part through a reader transmission. The received SOF symbol is used to calibrate the command decoder every time a command is received. This calibration is used to establish a pivot to distinguish between subsequent data ‘0’ and data ‘1’ symbols. Each time that a new command is received by the Transponder, the SOF re-calibrates the decode counter thereby compensating for any variation in the Transponder clock frequency due to changes in RF excitation levels or temperature variations. The circuit has been designed to accommodate a Transponder clock frequency variation of +/-40% from nominal. When the Transponder is transmitting the receive circuitry is disabled.

54H54HFig. 11). The Transponder requires

EM4223

All commands received from the Reader will have an immediate effect on the Transponder. In addition, certain commands will have a persistent effect. The possible immediate effects are one or both of the following:

 A change of State (see 55H55HFig. 19)  A Data Message sent to the Reader.

The possible persistent effects are:  Data Messages to the Reader will contain SUID (as

described later in this section) or Data Messages to the Reader will contain USER DATA of 128 bits,

 The Round Size (Number of Slots) over which all of

the Transponders in the population will spread their Data Messages to the Reader will be configured.

 The Transponder will switch between ISO and FST

modes of operation (as described below).

 A sub-population of Transponders will be enabled to

send Data Messages to the Reader dependent on either the AFI or on all or a portion of the USER DATA of 128 bits.

The start of a command from the Reader has a special significance if a Transponder is operating in the FST mode and is in the ROUND_ACTIVE state. When the falling edge of the first symbol of a command (SOF) is received by a Transponder in the ROUND_ACTIVE state while in FST mode, it will immediately move to the ROUND_STANDBY state. If a command is successfully received, the Transponder will move back to the ROUND_ACTIVE state. If the Transponder does not receive a valid command it will remain in the ROUND_STANDBY state until a valid command has been received. This enables the Reader to silence all Transponders that have not already started sending their Data Messages to the Reader in compliance with the FST protocol. It is important to note that the Reader does not have to send a full command or indeed even a part of a command, as long as it sends a low going pulse of approximately ½ Tari (Type A Reference Interval Time) duration.

An important feature of this transponder is its ability to switch seamlessly between ISO mode and FST mode whatever its “wake up” personality setting, depending only on the mode or characteristics of the controlling reader. A Transponder that “wakes up” in the ISO mode on powerup will switch to the FST mode if it receives a Wake_Up_FST command. Similarly, a Transponder that “wakes up” in the FST mode on power-up will switch to the ISO mode if it receives an INIT-ROUND, INITROUND-ALL or BEGIN-ROUND command.

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Transponders will only transmit Data Messages to the Reader while they are in the ROUND_ACTIVE state. When the CURRENT SLOT NUMBER and the SELECTED SLOT NUMBER values held by the Transponder match, the Transponder transmits its Data Message to the Reader. The Reply message will contain either the SUID (the Integrated Circuit Manufacturer code of 0x16 for MARIN and the lower 32 bits of the 128 bit User Data) or the 128 bit User Data .

In situations where different groups of transponders present in the reader field contain data having different owners, a reader may selectively wake up these different groups of transponders by means of the ISO compliant AFI parameter in the Init_Round command or by using the Mask parameter in the Begin_Round command. The Begin_Round command additionally supports selection of groups of transponders based on the user data content according to the EPC™ method.

General Command Format

All commands are transmitted from the Reader to the Transponder by means of pulse interval encoding as

defined in chapter 5: forward link encoding, beginning with

an SOF (Start Of Frame) and terminating in an EOF (End Of Frame). Commands are supported in accordance with the ISO 18000-6A specification which divides commands into the categories of MANDATORY, OPTIONAL, CUSTOM and PROPRIETARY. The EM4223 supports all of the ISO 18000-6A MANDATORY commands and 4 of the ISO 18000-6A OPTIONAL commands – Init_Round, Close_Slot, New_Round and Begin_Round. In addition, the EM4223 implements 1 PROPRIETARY command in accordance with the ISO 18000-6A specification – this is the Wake_Up_FST command which uses Op-Code 0x39.

Commands are divided into 2 basic types: Short Commands of a fixed 16 bit length and Extended commands which consist of a 16 bit section consistent with the Short Command format followed by a variable length extension containing various parameters and a second CRC of 16 bit length which covers the entire command, including the 1 been covered by the 5 bit CRC and the 5 bit CRC itself.

Supported Command set

The EM4223 fully supports the four ISO MANDATORY commands: NEXT_SLOT, STANDBY_ROUND, RESET_TO_READY and INIT_ROUND_ALL.

The ISO OPTIONAL commands: INIT_ROUND, CLOSE_SLOT, and NEW_ROUND are also supported.

11 bits which will already have

EM4223

The BEGIN_ROUND command is included for Supply Chain Logistics support. In addition to the above, the Fast Supertag commands: WAKE_UP_FST and MUTE are supported for compliance with the FST protocol. MUTE is interpreted as any partially decoded or invalid command as described in section

3. BASIC COMMAND FORMATS

There are 7 short commands, 2 extended commands and 1 implied command.

Short commands

Short commands are a fixed length of 16 bits, which includes a 5 bit CRC. The commands comprise the following fields:

 Protocol extension – 1 bit.  Command Op-code – 6 bits.  Parameters – 4 bits (parameters could include flags).  CRC – 5 Bits.

SOF RFU

Short commands are used for collision arbitration and other immediate functions.

Extended commands

The EM4223 supports 2 Extended commands

(Init_Round and Begin_Round). They comprise a fixed

length part of 16 bits, which is identical with the format of the 16 bit Short Commands described above, followed by an 8 bit fixed length parameter in the case of both of the Extended commands, followed by a 2 variable length up to 136 bits and terminated with a 16 bit CRC. The Extended commands comprise the following fields:

 Protocol extension – 1 bit.  Command Op-code – 6 bits.  Parameters – 4 bits (parameters could include flags).  CRC – 5 Bits.  Extension of 8 bits (AFI) in the case of the

 CRC-16 :- 16 Bits (over full message from after the

56H56H0.

(1 bit)

Command

Code (6 bits)

Fig. 3 General format, Short commands

Parameters &

Flags (4 bits)

CRC-5 (5 bits)

EOF

parameter of

INIT_ROUND command, or an 8 bit (MASK_LENGTH) parameter followed by a variable length (MASK) parameter in the case of the BEGIN_ROUND command

SOF to the last bit before the CRC16 itself).

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EM4223

SOF

RFU

(1 bit)

Command

Code

(6 bits)

Parameters

& Flags

(4 bits)

CRC-5 (5 bits)

The 2 Extended commands supported by the EM4223 are used to all selected sub-populations of Tags to be introduced to the Arbitration process.

Implied MUTE command (Fast Supertag Mode only)

When operating in the Fast Supertag Mode and in the ACTIVE state, the reception of the first low-going pulse of any command causes the EM4223 to move to the ROUND_STANDBY state. This could be any single pulse or the first pulse of the SOF of a valid command. The Transponder will continue to decode the command. A known and valid command causes the Transponder to execute the command and to move to either the ROUND_ACTIVE or the READY state, depending on the command and its parameters (if any). An unknown command or a command having an error will cause the Transponder to remain in the ROUND_STANDBY state.

Optional

Parameter

(8 bits)

2nd Optional

Parameter

(0-136 bit)

Fig. 4 - General format, Extended commands

CRC-16

16 bits

EOF

During reception of a command, and until the command has been correctly received, the Transponder will holdoff any attempt to reply until the command has been correctly received and executed. At the end of receiving a command, if it has not been correctly decoded, the Transponder will remain in the ROUND_STANDBY state until moved out of this state by the first correctly received and decoded command.

If the Tag is in the Fast Supertag Mode and in the TTF (Tag Talks First) sub-mode (Wake Up Status Flag = X00), the Tag will automatically leave the ROUND_STANDBY state after a timeout period of 2.5 X 176 tag bit periods has elapsed since the last MUTE command (176 bits = maximum Tag Data Message length).This timeout will be reset each time a new implied MUTE command is received.

Command Protocol

Init-Round Always = 0 01 SUID

Next-Slot Always = 0 02 * Signature 4 bits 5 bits The signature must match the

Close Slot Always = 0 03 Ignored by

StandbyRound

New-Round Always = 0 05 SUID

Reset-ToReady Init-RoundAll

Extension

Always = 0 04 * Ignored by

Always = 0 06 * Ignored by

Always = 0 0A * SUID

Op-

Code

bits

Parameter / flags

1 bit

EM4223

1 bit

EM4223

1 bit

4 bits

Round Size 3 bits

Round size 3 bits

CRC-5 Extended

5 bits AFI

5 bits Advances the CURRENT

5 bits The signature is not used in

5 bits

5 bits Moves Transponder from

5 bits SUID = 0 tag responds with

parameters

16 bits SUID = 0 tag responds with

8 bits

CRC-16 Comments

the 128 bits of user data. SUID = 1 tag responds with SUID. If AFI field = 00H, all tags respond, else if AFI is other value, only tags with matching AFI respond. Also moves tags already active in FST mode to ISO mode.

signature value transmitted by the tag in its last reply to acknowledge the tag’s reply. Advances the CURRENT SLOT COUNTER.

SLOT COUNTER.

this implementation because the EM4223 has no select state. The EM4223 will always move to the ROUND_STANDBY state.

current state to READY state.

the128 bits of user data. SUID = 1 tag responds with SUID. Also moves tags already active in FST mode to ISO mode.

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BeginRound

Wake-UpFST

Mute Low

Always = 0 OB SUID

Always = 0 39 SUID

Pulse

EM4223

1 bit

1 Bit

Round size 3 bits

Round size

5 bits Mask

length

8 bits

5 bits

Wakes tag up in the Fast

Mask value 0-136 bits

3 bits

Implied command in FST

16 bits Tags that match the MASK

value of MASK length will move to the ROUND_ACTIVE state from the ROUND_STANDBY or READY states or will remain in the ROUND_ACTIVE state if already there. Tags that do not match the Mask will move to the READY from either ROUND_ACTIVE or ROUND_STANDBY states. SUID = 0 tag responds with the 128 bits of user data. SUID = 1 tag responds with SUID, where the DSFID field is replaced by AFI field. Also moves Transponders already active in FST mode to ISO mode.

Supertag™ mode. Also moves tags already active in ISO mode to FST mode. SUID = 0 tag responds with the 128 bits of user data SUID = 1 tag responds with SUID.

mode. When tag receives an SOF it moves to the ROUND_STANDBY state. The tag returns to the active state on receipt of a next-slot or init-round or new-round command, or when a period of

2.5 X 176 tag bit periods has elapsed since the last Mute command (176 bits = maximum message length).

Mandatory ISO commands op-codes are marked with an * and command titles are in bold type face.

Table 5- Supported Commands

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Reader Command Transponder Operation in

ISO Mode

INIT_ROUND Initialises the start of the arbitration sequence

and tells the Transponder over how many slots to randomise the transmit slot selection. Configures the Transponder to transmit the SUID data or the full 128 bit User Data to the Reader dependent on the SUID parameter in the command. Moves the Transponder from the READY to the ROUND_ACTIVE states if the Transponders AFI matches the AFI in the command or if the AFI in the command = 0x00 . If the AFI in the command is non-zero and does not match the AFI in the Tag, causes the Tag to move from the ROUND_ACTIVE to the READY states.

BEGIN_ROUND Initialises the start of the arbitration sequence

and tells the Transponder over how many slots to randomise the transmit slot selection. Configures the transponder to transmit the SUID data where DSFID field is replaced by AFI field, or the full 128 bit User Data to the reader, depending in the SUID parameter in the command. Moves the Transponder from the READY to the ROUND_ACTIVE states if the number of bits of the Transponders User Data specified in the command is identical to the matching data in the command Mask parameter .

INIT_ROUND_ALL Initialises the start of the arbitration sequence

NEW_ROUND Causes the EM4223 to enter a new Round and

to change the number of pseudo-slots over which it randomises its transmissions. Tags in the READY state will ignore this command.

WAKE_UP_FST Not supported in ISO Mode – causes the

Transponder to immediately switch to Fast

Supertag Mode.

EM4223

Transponder Operation in

Fast Supertag Mode

Not supported in Fast Supertag Mode – causes the Transponder to immediately switch to ISO Mode.

Causes the EM4223 to change the number of pseudo-slots over which it randomises its transmissions. Tags in the READY state will ignore this command.

Initialises the start of the Fast Supertag arbitration sequence and tells the Transponder over how many slots to randomise the transmit slot selection. Configures the Transponder to transmit the full 128 bit User Data to the Reader irrespective of the SUID parameter in the command. Moves the Tag from the ROUND_STANDBY to the ROUND_ACTIVE states or from the READY to the ROUND_ACTIVE states if the Mask parameter matches, else moves Tag to the READY state.

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NEXT_SLOT

CLOSE_SLOT

STANDBY_ROUND

RESET_TO_READY Moves the Transponder from its current state to

MUTE – this is not an actual command but is an implied command derived from the first low-going pulse of any command.

Acknowledges the successful reception of a Transponder transmission by the Reader when valid ie. when received by a Transponder which has just transmitted, and when the command is received in the timing window and when the Signature matches, causing the Transponder to move from the ROUND_ACTIVE to the QUIET states.

Causes a Transponder in the ROUND_STANDBY state to move into the ROUND_ACTIVE state.

Causes the Transponder Current Slot Counter to increment by one.

Causes the Transponder to automatically start a new Round by resetting its Current Slot Counter and randomly selecting a new Reply Slot when the Current Slot Counter has reached the Round Size Value.

Causes a Transponder in the ROUND_STANDBY state to move into the ROUND_ACTIVE state.

Causes the Transponder slot counter to increment by one.

Causes the Transponder to automatically start a new Round by resetting its Current Slot Counter and randomly selecting a new Reply Slot when the Current Slot Counter has reached the Round Size Value.

Causes the Transponder to move to the ROUND_STANDBY state, in which the Transponder does not transmit its identity or data.

READY state.

Not used. The Transponder will move to the

EM4223

Causes a Transponder in the ROUND_STANDBY state to move into the ROUND_ACTIVE state.

Causes the Transponder to move to the ROUND_STANDBY state, in which the Transponder does not transmit its identity or data. While in the ROUND_STANDBY state, the random number generator for slot number choosing is running so that transponder slots are not synchronized and thus have maximum spread and randomisation in the Transmit times. When the Transponder exits the ROUND_STANDBY state, it will wait until the next internally generated slot time before reenabling its data transmit circuitry.

Moves the Transponder from its current state to READY state.

ROUND_STANDBY state upon reception of the first low-going pulse of any command. This could be any single pulse or the first pulse of the SOF of a valid command. The Transponder will continue to decode the command and if the pulse turns out to be part of a valid command, the Transponder will move to either the READY or the ROUND_ACTIVE state depending on the actual command and the command parameters. If the WUS bit = 0 the Transponder will automatically leave the ROUND_STANDBY state after a timeout period of 2.5 X 176 tag bit periods has elapsed since the last MUTE command (176 bits = maximum Data Message length).This timeout will be reset each time a new implied MUTE command is received.

Table 6– Command Operations

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EM4223

Command state transitions

The following tables show the state transitions for each of the commands supported by the EM4223 and should be read in conjunction with

57H57HFig. 19.

Command : Init_Round (Tag will be in ISO mode after this command)

Initial State Criteria Action New State

AFI in the command = 0 or tags AFI value matches the value in the command.

AFI in the command <> and Tags AFI value <>

Quiet None None Quiet

Round_Standby

AFI value in the command.

AFI in the command = 0 or tags AFI value matches the value in the command.

AFI in the command <> and Tags AFI value <> AFI value in the command. AFI in the command = 0 or tags AFI value matches the value in the command.

AFI in the command <> and Tags AFI value <> AFI value in the command.

Tag chooses a random slot in which it will send its response. Tag’s Current Slot Counter is reset to first slot. None Ready

Tag chooses a new random slot in which it will send its response. Tag’s Current Slot Counter is reset to first slot. None Ready

Tag chooses a new random slot in which it will send its response. Tag’s Current Slot Counter is reset to first slot.

None Ready

Table 7 – Tag state transitions for Init_Round

Round_Active Ready

Round_Active Round_Active

Round_Active

Command : New_Round

Initial State Criteria Action New State

Ready None None Ready

Quiet None None Quiet

Round_Active None Tag chooses a new random slot in which

it will send its response. Tag’s Current Slot Counter is reset to first slot.

Round_Standby None Tag chooses a new random slot in which

it will send its response. Tag’s Current Slot Counter is reset to first slot.

Table 8 – Tag state transitions for New_Round

Round_Active

Command : Init_Round_All (Tag will be in ISO mode after this command)

Initial State Criteria Action New State

Ready None Tag chooses a random slot in which it

will send its response. Tag’s Current Slot Counter is reset to first slot.

Quiet None None Quiet

Round_Active None Tag chooses a new random slot in which

it will send its response. Tag’s Current Slot Counter is reset to first slot.

Round_Standby None Tag chooses a new random slot in which

it will send its response. Tag’s Current Slot Counter is reset to first slot.

Table 9 – Tag state transitions for Init_Round_All

Round_Active

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EM4223

Command : Begin_Round (Tag will be in ISO mode after this command)

Initial State Criteria Action New State

Ready

Number of bits of the MASK specified by MASK_LENGTH in the command matches the data in the Tag (AFI followed by USER DATA).

If the 1

8 bits of the MASK = 0 they are not

Tag chooses a random slot in which it will send its response. Tag’s Current Slot Counter is reset to first slot.

compared. Number of bits of the MASK specified by

None Ready MASK_LENGTH in the command does not match the data in the Tag.

Quiet None None Quiet

Round_Active

Number of bits of the MASK specified by MASK_LENGTH in the command matches the data in the Tag (AFI followed by USER DATA).

If the 1

8 bits of the MASK = 0 they are not

Tag chooses a new random slot in which

it will send its response. Tag’s Current

Slot Counter is reset to first slot.

compared. Number of bits of the MASK specified by

None Ready MASK_LENGTH in the command does not match the data in the Tag.

Round_Standby

Number of bits of the MASK specified by MASK_LENGTH in the command matches the data in the Tag (AFI followed by USER DATA).

If the 1

8 bits of the MASK = 0 they are not

Tag chooses a new random slot in which

it will send its response. Tag’s Current

Slot Counter is reset to first slot.

compared. Number of bits of the MASK specified by

None Ready MASK_LENGTH in the command does not match the data in the Tag.

Table 10 – Tag state transitions for Begin_Round

Round_Active

Command : Wake_Up_FST (Tag will be in FST mode after this command)

Initial State Criteria Action New State

Ready None Tag chooses a random slot in which it

will send its response. Tag’s Current Slot

Counter is reset to first slot.

Quiet None None Quiet

Round_Active None Tag chooses a new random slot in which

it will send its response. Tag’s Current

Slot Counter is reset to first slot.

Round_Standby None Tag chooses a new random slot in which

it will send its response. Tag’s Current

Slot Counter is reset to first slot.

Table 11 – Tag state transitions for Wake_Up_FST

Round_Active

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EM4223

Command : Next_Slot

Initial State Criteria Action New State

Ready None None Ready

Quiet None None Quiet

Round_Active

Tag has answered in previous slot, AND Signature matches AND 1

low pulse of Next_Slot command was received in the acknowledgement time window. Tag is in ISO Mode and has NOT answered in previous slot, OR Signature does not match OR 1

low pulse of Next_Slot command was not received in the acknowledgement time window. Tag is in FST Mode and has NOT answered in previous slot, OR Signature does not match OR 1

low pulse of Next_Slot command was not received in the acknowledgement time window. ISO Mode The tag shall increment its slot counter

FST Mode The tag resumes the FST Arbitration

None Quiet

The tag shall increment its slot counter

Round_Active

and send its response if slot counter matches the chosen slot.

The tag will automatically increment is

Round_Active Current Slot Counter at internally determined times and send its response if the its Current Slot Counter matches its Selected Slot Register.

Round_active Round_Standby

and send its response if slot counter matches the chosen slot.

Round_active

process and will automatically increment is Current Slot Counter at internally determined times and send its response if the its Current Slot Counter matches its Selected Slot Register.

Table 12 - Tag state transitions for Next_Slot

Command : Close_slot

Initial State Criteria Action New State

Ready None None Ready

Quiet None None Quiet

Round_Active

ISO Mode The tag shall increment its slot counter

Round_Active and send its response if slot counter matches the chosen slot.

FST Mode The tag will automatically increment is

Round_Active Current Slot Counter at internally determined times and send its response if the its Current Slot Counter matches its Selected Slot Register.

ISO Mode The tag shall increment its slot counter

Round_active Round_Standby

and send its response if slot counter matches the chosen slot.

FST Mode The tag resumes the FST Arbitration

Round_active

process and will automatically increment is Current Slot Counter at internally determined times and send its response if the its Current Slot Counter matches its Selected Slot Register.

Table 13 - Tag state transitions for Close_Slot

Command : Reset_To_Ready

Initial State Criteria Action New State

Ready None None Ready

Quiet None None Ready

Round_Active None None Ready

Round_Standby None None Ready

Table 14 - Tag state transitions for Reset_To_Ready

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EM4223

Command : Standby_Round

Initial State Criteria Action New State

Ready None None Ready

Quiet None None Quiet

Round_Active None None Round_Standby

Round_Standby None None Round_Standby

Table 15 – Tag state transitions for Standby_Round

4. GENERAL REPLY FORMAT

The Transponder will reply to a successful arbitration sequence by sending a message having the following format:

 Preamble – see description of the Return Link.  Flags – 2 bits (Preset)  Parameters as follows:  Transponder type – 1 bit (Always = 0)  Battery status – 1 bit (Always = 0)  Signature – 4 bits (last 4 bits of the clock counter).  Data – 136 bits if the SUID bit = 0 as follows:

 AFI of 8 bits.

User Data of 128 bits.



 Data – 48 bits if the SUID bit = 1 as follows:

 DSFID of 8 bits.

SUID of 40 bits (lower 32 bits of User Data + IC Manufacturer code).



 CRC – 16 bits

Preamble Flags Parameters Data CRC

Fig. 5- Transponder Reply, general format

Preamble Flags Trans. Type Battery

Status

2 bits Always = 0 Always = 0 4 bits 8 bits 128 bits 16 bits

The above reply will be received after a successful arbitration sequence that was initiated by the Init-Round, Init-RoundAll, Begin_Round and Wake-Up_FST commands with the SUID flag = 0.

Signature AFI USER DATA CRC16

Fig. 6 – Transponder Reply to commands with the SUID flag = 0.

Preamble Flags Trans. Type Battery Status Signature DSFID SUID CRC 16

2 bits Always = 0 Always = 0 4 bits Always = 0x00 40 bits 16 bits

Fig. 7 – Transponder Reply commands with the SUID flag = 1.

The above reply will be received after a successful arbitration sequence that was initiated by the Init_Round, Init_Round_All and Wake_Up_FST commands with the SUID flag = 1.

Preamble Flags Trans. Type Battery Status Signature AFI SUID CRC 16

2 bits Always = 0 Always = 0 4 bits 8 bits 40 bits 16 bits

Fig. 8 – Transponder Reply to Begin_Round command with the SUID flag = 1.

The above reply will be received after a successful arbitration sequence that was initiated by the Begin_Round command with the SUID flag = 1.

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5. FORWARD LINK ENCODING - READER TO TRANSPONDER

Commands and data are received from the Reader, encoded by means of Pulse Interval Encoding. The Reader transmits pulses in the form of dips in its carrier wave. The intervals between dips convey information in accordance with the following description.

The Transponder responds to transmissions by the Reader as described herein.

Carrier modulation pulses

The data transmission from the Reader to the Transponder is achieved by modulating the carrier amplitude (ASK). The data coding is performed by generating pulses at variable time intervals. The duration of the interval between two successive pulses carries the data coding information. This is known as Pulse Interval Encoding, (PIE). The Transponder measures the interpulse time on the high to low transitions (falling) edges of the pulse as shown in 58H58HFig. 9

Basic time interval – definition of “Tari”

The time “Tari” specifies the period in microseconds between two falling edges representing the symbol “0”. The word “Tari” is an acronym for “Type A Reference Interval Time” as defined in the ISO18000-6 Type A specification. The period between the two falling edges defining each of the other symbols is based on a multiple of the basic Tari period. The SOF symbol (Start of Frame) consists of 2 periods, the 1

of which is equal to

EM4223

One Tari, while the 2nd period of the SOF symbol is equal to 3 Tari. The first part of the SOF symbol is provided to allow detector circuitry to settle (should this be necessary). The second part of the SOF symbol is used as a Calibration period. The received SOF symbol is used to calibrate the command decoder every time a command is received. This calibration is used to establish a pivot to distinguish between subsequent data ‘0’ and data ‘1’ symbols. The pivot point has a value of

1.5Tari and is derived from the 3Tari interval contained in

part of the SOF symbol. The binary data ‘0’ and

the 2 ‘1’ are extracted from the incoming data stream by comparing the inter-pulse interval with a pivot point. If the interval is less than the pivot, then the binary value is ‘0’ and if it is greater than the pivot then the binary value is ‘1’ (See clause received by the Transponder, the SOF re-calibrates the decode counter thereby compensating for any variation in the Transponder clock frequency due to changes in RF excitation levels or temperature variations. The circuit has been designed to accommodate a Transponder clock frequency variation of ±40% from nominal. The basic Tari period as transmitted by the Reader is specified in

Tari

59H59H0). Each time that a new command is

60H60HTable 16 and illustrated in 61H61HFig. 9.

Tari Tolerance

20 µs ±100 ppm

Table 16 - Reference interval timing

100%

Fig. 9 - Inter-pulse mechanism

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Data coding

Data transmitted by the Reader to the Tag is encoded in PIE format as described in

62H62H0 and 63H63H0 above. Four symbols

are encoded; ‘0’, ‘1’, SOF and EOF. The Transponder is able to decode symbols having values as shown in

64H64HFig.

10 below.

Symbol Mean

duration

0 1 Tari ½ Tari < ‘0’ ≤ 3/2 Tari 1 2 Tari 3/2 Tari < ’1’ < 3 Tari

SOF

1 Tari followed

by 3 Tari

EOF 4 Tari ≥ 4 Tari

Table 17 - PIE symbols

Limits

Calibration sequence

EM4223

Values falling outside of the limits in

17 will cause the received data to be rejected and

Table the EM4223 to wait for an unmodulated carrier of EOF duration or greater before being ready to receive a new command.

Time interval in "Tari"

Symbol

'0'

'1'

'EOF'

'SOF'

Fig. 10 - PIE symbols

1234

65H65H

Data Frame format

The bits transmitted by the Reader to the Transponder are embedded in a frame as specified in

66H66HFig. 11. Before

sending the frame, the Reader ensures that it has established an unmodulated carrier for duration of at least Taq (Quiet time) of 300µs.

Taq

1Tari

3 Tari

BBB B

Quiet

SOF

The frame consists of a Start-Of-Frame (SOF), immediately followed by the data bits and terminated by an End-Of-Frame (EOF). After sending the EOF the Reader maintains a steady carrier for sufficient time to allow all Transponders present to be powered so that

they may send their Reply.

Command + Data

EOF

Fig. 11 - Forward link frame format

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Data decoding

The binary data ‘0’ and ‘1’ are extracted from the incoming data stream by comparing the inter-pulse interval with a pivot point. The pivot point has a value of

1.5Tari and is derived from the 3Tari interval contained in the 2nd part of the SOF symbol. If the interval is less than the pivot, then the binary value is ‘0’ and if it is greater than the pivot then the binary value is ‘1’.

1100

EM4223

If the Transponder detects an invalid code it discards the frame and waits for an unmodulated carrier of EOF duration. No Error Messages are sent to the Reader.

Bits and byte ordering

Coding of data into symbols is MSB first. The coding for the 8 bits of hex byte 'B1' is shown in

67H67HFig. 12.

Ts0

Reader to Transponder 5 bit CRC (CRC-5)

The CRC-5 is used only for commands from the Reader to the Transponder. All commands have a CRC-5 as the last 5 bits of the first 16 bit part of an Extended command or as the last 5 bits of a Short Command. The CRC-5 is calculated on all the command bits after the SOF up to the end of the Extended Parameters (11 bits in total – see

68H68HFig. 3).

The polynomial used to calculate the CRC-5 is x^5 + x^3 +1. The CRC-5 register is pre-loaded with '01001' (MSB (C4) to LSB (C0)) prior to commencing a CRC-5 calculation in both the case of a Reader to Transponder command transmission and the case of a Transponder initializing its CRC-5 register prior to receiving a command from the Reader.

The 5 bits of the CRC-5 embedded in the command are received MSB first by the Transponder. The Transponder will clock the first 16 bits of an Extended command or a complete Short Command through its CRC-5 register as it is receiving the command from the Reader and if these 16 bits were received without error, the Transponder’s CRC-5 register will contain all zeros after the last bit has been clocked through.

Command Decoder

The Transponder can receive commands from a Reader at any time other than the time that it is transmitting a

Fig. 12 - Example of PIE byte encoding for 'B1'

Reply to the Reader and during the 2 Transponder bit

periods following a Reply transmission.

In the case of the Next_Slot command the command is interpreted by the Transponder in one of two ways.

 If a Next_Slot command is received such that the

first pulse of the command is received during the active command window of the Transponder, which follows a transmission by the Transponder and this Next_Slot command contains a signature parameter that matches that sent by the Transponder in its last transmission, then the command will be interpreted as an instruction for that Transponder to move to the quiet state

 69H69HFig. 13 and below show the timing of the

Transponder command window.

 If a Next_Slot command is received at any time

other than coincident with an active command window (opened by the Transponder following a transmission) or if the Transponder had not

transmitted a Reply immediately prior to receiving

the NEXT_SLOT command or if the Next_Slot command does not contain a signature parameter that matches that sent by the Transponder in its last transmission then the command is interpreted as an instruction to step the current slot counter value in ISO mode or as a command to exit the ROUND_STANDBY state in either ISO or FST modes.

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EM4223

Tag bits after last transmitted bit

carrier modulated state level

Tag not reflecting

Tag

transmission

Tag listens

Interrogator

RF field

End of last

carrier steady

state level

tag bit

123456

the last tag data transition occurs at either the centre or end of the last bit period depending on FM0 state.

Tag Command Window

1st high to low transition of the

command shall occur in this time.

Fig. 13 - Command Window Timing

6. RETURN LINK DATA ENCODING - TRANSPORTER TO READER

The return link data is modulated onto the impinging illuminating RF carrier using varying impedance modulation.

Return link data encoding

Data is encoded using Bi-phase space (FM0).

FM0 Data Coding

MSB first encoding of Byte 10110001 = 'B1'

lternative depending on prior conditions

100

Trlb

Fig. 14 - Return link – data encoding

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Return link preamble

The FM0 return link preamble has the bit pattern described in Error! Reference source not found.

Tag bit periods

23 45 6 7 8

Preamble waveform

1' is tag reflecting, '0' is tag not reflecting

910

11 12

Fig. 15 - FM0 Return link preamble

Cyclic Redundancy Check (CRC)

The 16 bit CRC is calculated on all data bits up to, but not including, the first CRC bit. The polynomial used to calculate the CRC is x^16 + x^12 + x^5 + 1.

MSByte LSByte

MSB LSB MSB LSB

CRC 16 (8 bits) CRC 16 (8 bits)

 first transmitted bit of the CRC

The 16-bit register is preloaded with 'FFFF’. The resulting CRC value is inverted, attached to the end of the packet and transmitted. The most significant byte shall be transmitted first. The most significant bit of each byte shall be transmitted first.

EM4223

7. MEMORY ORGANISATION AND CONFIGURATION INFORMATION

Memory Map

The physical memory comprises 128 bits of user memory, 8 bits AFI and 3 personality bits. In addition, the IC Manufacturer Code as specified in ISO7816-6/AM1 is hard-wired into the Transponder.

128 bits UUD memory 8 bit AFI 3 bits Personality

Fig. 17- Memory map

Unambiguous User Data (UUD) & SUID

The user memory on the Transponder comprises 128 bits of user specified data. This data is known as Unambiguous User Data UUD, because it is expected that this data be unique and unambiguous. The UUD is a license plate defined by the user and may be an EPC™, GTAG™ or other user defined number. The Transponder will return a Sub-UID (SUID) as defined in ISO 18000-6 when the SUID flag is =1 in the arbitration initiation commands. The SUID in this Transponder is derived from the least significant 32 bits of the UUD as described below. The SUID consists of 40 bits: the 8 bit manufacturer code followed by the least significant 32 bits of the UUD.

Fig. 16- CRC format

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MSB

Upper bits of UUD

MSB LSB

40 33 32 1 IC Mfg code “0x16”

Hard wired in EM4223.

Transponder Unique Identifier (UID) & SUID

An ISO 18000-6A Transponder does not transmit the UID except in response to the optional Get_System_Information command which is not supported in the EM4223. All other transactions are conducted using the SUID (which is supported).

The Interrogator derives the Transponder 64 bit UID from the SUID and it is made up as follows:

 Bits 57 Æ 64 are always set to Hex ‘E0’.  Bits 49 Æ 56 carry the Integrated Circuit

Manufacturers Code

 Bits 33 Æ 48 are always set to Hex ‘0000’  Bits 1 Æ 32 carry the 32 bit Serial number.

AFI

Application Family Identifier - 8 bits per ISO 18000-6 clause 7.2.3. If the AFI byte is set with all 00 the tag will respond, or if the AFI in the tag matches the AFI byte in the init-round command the tag will respond, otherwise the tag will remain quiet.

Wake Up

FST/ISO Flag

(pbit 1)

1 1 READY – Transponder replies in its selected

1 0 READY - Transponder replies in both the first

0 1 ROUND_STANDBY state, Reader Talks First

0 0 ROUND_ACTIVE –Tag Talks First mode SUID flag = 0

Personality Block 0- Bit 2 determines the Transponder Reply data rate:

0 = 40 kb/s 1 = 160 kb/s

Status

Flag

(pbit 0)

128 40 33 32 1

Serial number (Lower 32

Serial number

Personality Block

The personality block contains 3 control bits. The default

ISO

state of these bits is programmed during manufacture. These bits control the Wake Up Status flag (WUS), the power up selection of FST or ISO mode of operation and the Return Link Bit Rate. Transponders will power up in the default mode set by the bits programmed during manufacture. Only the FST/ISO mode flag can be changed by Reader commands. Transponders will be switched to FST mode by the WAKE_UP_FST command. INIT_ROUND, INIT_ROUND_ALL and BEGIN_ROUND commands will switch Transponders to the ISO mode of operation.

The state of the WUS bit cannot be changed from the value set during manufacture. Transponders will operate in ISO or MOD_ISO mode depending on the factory programmed state of the WUS bit. Similarly, Transponders will operate as TTF or as RTF in FST mode depending on the factory programmed state of the WUS bit. It is important to note that tags can only switch between MOD_ISO and FST (TTF) or between ISO and FST (RTF) modes.

Transponder SUID and

Tag State

Roundsize Initialize

Power Up Condition

slot in each round.

slot and its selected slot in every round

mode

Table18 - Transponder Operational Modes

EM4223

LSB

bits of UUD)

Fig. 18- UUD/SUID mapping

Mode

Conditions

Don’t care ISO

Don’t care MOD_ISO

SUID flag = 0

Roundsize = 16

FST (RTF)

FST (TTF)

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8. TRANSPONDER SELECTION OPERATION – INIT_ROUND AND BEGIN_ROUND COMMANDS

The INIT_ROUND and BEGIN_ROUND commands have the ability to move only a selected sub-set of the Transponder population from the READY to the ROUND_ACTIVE states. Transponders that are already in the ROUND_ACTIVE or ROUND_STANDBY states will be removed from the active Transponder population and moved to the READY state if they do not match the selection parameters sent with the INIT_ROUND or BEGIN_ROUND command. This allows the population to be “thinned”, thus increasing the effective read rate achieved.

EXPLANATION OF “DETERMINISTIC” OPERATION BASED ON “TREE-WALKING”

Transponders that use randomly selected reply slots in order to transmit their data to a Reader have a very small risk of more than one Transponder selecting the same slot several times, which could mean that such tags may not be read before they move out of the active population. This is known as “Probabalistic” operation and must be balanced against the many advantages of this mode of operation. “Tree Walking” is a method of resolving Transponder populations by effectively issuing a series of “tests” or “challenges” in which the Reader would request a response from all tags containing say “0” in the 1 position of the Transponder data (or in an encrypted version of the data). If the Reader received a nonclashing response (only 1 transponder responding) it could request that Transponder to send its full data. If the Reader received a clashing response (more than 1 transponder responding) it would know that it had identified a productive “branch” and would extend its test by requesting a response from all tags containing say “00” in the 1

two bit positions of the Transponder data. It would continue testing and requesting responses until it had resolved the entire tag population in this manner. If the Reader received no response it would know that it had identified an unproductive “branch” and would temporarily abandon further testing for Transponders with “0” in the 1

Transponders with “1” in the first bit position. This would continue until all Transponders had been identified, or moved out of the Reader’s RF field.

INIT_ROUND COMMAND SELECTION OPERATION

70H70HFig. 19)

(see

The INIT_ROUND command contains a single fixed length (8 bit) selection parameter. This parameter represents the AFI (Application Family Identifier according to ISO18000-6A) value which will be matched with the AFI value contained in the Transponders memory. Transponders with a matching AFI value will move from the ROUND_ACTIVE or ROUND_STANDBY or READY states to the ROUND_ACTIVE state and commence participation in the Arbitration process. Transponders that do not match the AFI value sent in the command will remain in the READY state or they will move to the READY state if they are already in the ROUND_ACTIVE or ROUND_STANDBY states.

EM4223

Because only transponders of interest to the application will be selected any other Transponders in the Reader field will not degrade Reader performance by needing to be read and acknowledge to send them to the QUIET state – they virtually do not exist if they have not been selected.

The selection capabilities also allow the Transponder population to be “Tree-Walked” allowing fully “Deterministic” arbitration of a Transponder population. By adding more and more bits to the selection criteria, the population can be resolved down to a single Transponder. (See the explanatory note below).

bit

bit position. The Reader would then test for

If the AFI value contained in the INIT_ROUND command is 0x00, the Transponders will ignore the parameter in the command and all Transponders will move to the ROUND_ACTIVE state from the ROUND_ACTIVE or ROUND_STANDBY or READY states. With an AFI parameter of 0x00, the command will perform identically to an INIT_ROUND_ALL command.

Tags in the QUIET state will ignore the INIT_ROUND command.

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BEGIN_ROUND COMMAND SELECTION OPERATION

71H71HFig. 19)

(see

The BEGIN_ROUND command contains 2 selection parameters. The 1

parameter, called MASK_LENGTH, consists of a fixed length (8 bit) value, which specifies how many bits will be sent in the following parameter, called the MASK. This MASK_LENGTH will be between 0 and 136 for the EM4223. The MASK value will be compared to the number of bits of the tags data memory specified in the MASK LENGTH parameter. Transponders with data matching the MASK in the command will move from the ROUND_ACTIVE or ROUND_STANDBY or READY states to the ROUND_ACTIVE state and commence participation in the Arbitration process. Transponders whose data does not match the MASK

value sent in the command will

remain in the READY state or they will move to the READY state if they are already in the ROUND_ACTIVE or ROUND_STANDBY states.

EM4223

The MASK value is transmitted MSB 1 MASK is compared to the MSB of the Transponders AFI,

the 2

bit of the MASK is compared to the 2nd most

significant bit of the Transponders AFI and so on, up to

the 8

bit of the MASK, which is compared to the AFI. If

the 1

8 bits of the MASK contain the value B00000000, the result of the comparison of the 1 to the AFI is forced to a Match result. If the MASK_LENGTH is less than 8 bits, then the number of bits of the Transponder’s AFI compared to the MASK is determined by the MASK_LENGTH parameter.

The 9

to the 136th bits of the MASK is compared to the 128 bit USER DATA in the Transponder – in other words, bit 9 of the MASK is compared to the MSB of the USER DATA and so on down to bit 136 of the MASK being compared to the LSB of the USER DATA. The number of bits of the USER DATA compared to the MASK is equal to MASK_LENGTH – 8 if MASK_LENGTH > 8. If MASK_LENGTH ≤ 8 no USER DATA bits will be compared to the MASK.

Tags in the QUIET state will ignore the BEGIN_ROUND command.

. The 1st bit of the

8 bits of the MASK

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EM4223

9. COMMANDS AND STATES

Commands

The EM4223 supports the commands as specified in 72H72HTable 5- Supported Commands and as set out in ISO/IEC CD 180006A clause 7.6 and clause 7.7.

Tag States

FST = 0 & WUS = 1 & RF field on FST = 0 & WUS = 0 & RF field on

Quiet Flag set ( power off < 2 secs)

Reset_to_ready

Begin_Round(Match) #

Init_Round(Match) #

Init_Round_All #

Wake_Up_FST @

RF FIELD OFF

READY

Reset_To_Ready Begin_Round(Unmatch) # Init_Round(Unmatch) #

QUIET

All commands except:

"Reset_To_Ready"

2.5 Message Timeout if FST = 0 & WUS = 0

Incomplete or Unrecognised Cmnd

Reset_To_Ready Begin_Round(Unmatch) # Init_Round(Unmatch) #

Next_Slot (OK)

Begin_Round(Match) #

Standby_Round

ROUND_ACTIVE

Next_Slot (Not OK)

Close_Slot

New_Round

Init_Round(Match) #

Init_Round_All #

Wake_Up_FST @

ROUND_STANDBY

Fig. 19– State transition diagram showing commands.

Next_Slot (Not OK) Close_Slot New_Round End of FST Tag Internal Slot Begin_Round(Match) # Init_Round(Match) # Init_Round_All # Wake_Up_FST @

Standby_Round (Incomplete or Unrecognised Cmnd) & FST=0

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EM4223

NOTES:

 Commands marked with the "#" character will place

tags in the "ISO" mode of operation. These are the "Begin_Round", "Init_Round" & "Init_Round_All" commands.

 The "Wake_Up_FST" command marked with the

"@" character will place tags in the "FST" mode of operation.

 The last Mask selection made in the "ISO" mode

will be retained when switching from the "ISO" to the "FST" mode.

 "Next_Slot(OK)" will only occur when the tag

receiving the "Next_Slot" command receives the command in the command window immediately following its transmission to the Reader and if the "Next_Slot" command contained the same

Tag state storage

In the case where the Transponder loses the energizing field for short periods of time (eg. when moving), the Transponder retains its state for at least 300µs. In addition, if the Transponder is in the Quiet state, it retains its Quiet state for at least 2s.

State Description Commands to which responsive

The Transponder is out of the RF field

RF field off

READY

ROUND_ACTIVE

ROUND_STANDBY ROUND_ACTIVE state is suspended

QUIET (Persistent Sleep)

or the Reader Tx Carrier is switched off. The Transponder is in an RF field, its clock is running and it is waiting for a command.

The Transponder steps through the hold-off loop and will transmit if it has reached its turn to transmit

The Transponder is unresponsive to commands and the hold-off loop has been suspended. It will only respond to a Reset-To-Ready command or will reset when removed from the RF field for an extended period of time typically greater than 2 seconds.

SIGNATURE value as sent by the tag to the Reader as part of its transmission. In all other cases the "Next_Slot" command will be accepted as "Next_Slot (Not OK)".

 Tags will automatically start a new round without a

"Begin_Round", "New Round", "Init_Round" or "Init_Round_All" command when they receive a "Next_Slot" or "Close_Slot" command while their internal "Current Slot Counter" indicates the last slot in the current round. This will also apply to tags being moved from the ROUND_STANDBY state to the ROUND_ACTIVE state by a "Next_Slot" or "Close_Slot" command.

Note: Implementation of the Quiet state storage may

imply that the Transponder will retain this condition during a time greater than 2s, up to several minutes in low temperature conditions. The Reset_to_Ready command overrides the Quiet state under these circumstances.

None.

Wake-Up_FST, Init-Round-All, InitRound, Begin-Round

None required, responsive to all commands according to the collision arbitration loop. Standby_Round will move the Transponder to the ROUND_STANDBY state. Next-Slot, Close-Slot, New-round, InitRound, Init-Round-All, Begin-Round, Reset-To-Ready, Wake-Up-FST & Time-Out

Reset-To-Ready

Table19 - Transponder States

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10. COLLISION ARBITRATION

The EM4223 implements the ISO 18000-6 Type A anticollision scheme as described in CD ISO-IEC 18000 part 6 Type A. Additionally, the EM4223 implements the Fast Supertag

The basic collision arbitration scheme is based on slots. The ISO implementation uses regimented slots that are controlled by the Reader. Fast Supertag slots (non-synchronised slots) by virtue of the fact that transmissions are initiated in integer multiples of a slot time. However because Transponder clocks will not be identical and because the Reader does not synchronize slots at the start of each slot, there will be a natural drift and the timing of slots between individual Transponders will diverge.

Refer to the state diagram,

General explanation of the collision arbitration mechanism

The collision arbitration uses a mechanism, which allocates Transponder transmissions into rounds and slots. A round consists of a number of slots. A Transponder will only transmit once in a round unless the Transponder is in ISO mode and the WUS bit= 0, in which case the Transponder will reply in the first slot as well as in its chosen slot, or only in the first slot if the first slot was selected as the The time position where it transmits in a round is determined randomly.

ISO COMPLIANT SYSTEMS

Each slot has a duration at least as long as a Transponder transmission or as long as the Reader requires to identify an unproductive (empty) slot and send the CLOSE_SLOT command to the Transponder population. The Reader determines the duration of the slot by closing slots with CLOSE_SLOT or NEXT_SLOT commands in response to successful data replies from Transponders or clashing replies from Transponders or in response to identifying an empty slot.

On receiving an Init_round command, Transponders randomly select a slot in which to respond. If a Transponder has selected the first slot it will transmit its

Reply. The Transponder includes its four-bit

Transponder signature in its has selected a slot number greater than one, it will retain its slot number and wait for a further command.

After the Reader has sent the Init_round command there are three possible outcomes:

1. The Reader does not receive a Reply because

 anti-collision protocol.

 uses pseudo-

73H73HFig. 19.

Reply slot by the Transponder.

Reply. If the Transponder

either no Transponder has selected slot one or the Reader has not detected a Transponder Reply. The Reader then issues a Close_Slot command because it has not received a Reply.

EM4223

2. The Reader detects a collision between two or more

Transponder replies. Collisions may be either as contention from the multiple transmissions or by detecting an invalid CRC. After waiting until the channel is clear, the Reader sends a Close_Slot command to increment the Transponder slot counter.

3. The Reader receives a Transponder Reply without

error, i.e. with a valid CRC. The Reader sends a Next_slot command synchronized to the Transponder timing window, containing the signature of the Transponder just received.

When Transponders in the ROUND_ACTIVE state that have not transmitted in the current slot receive a Next_slot command or a Close_Slot command, they increment their slot counters by one. When the slot counter equals the slot number previously selected by the Transponder, the Transponder transmits according to the rules above otherwise the Transponder waits for another command.

The Reader keeps track of the slot count each time it issues a Next_slot command or Close_Slot command. When the number of slots used equals the round_size issued in the Init_round command, the round has completed and the Reader may issue a round initializing command. (Note: A Reader may issue a round initializing command at any time).

Transponders that have not been acknowledged (by a synchronous Next_Slot command with a valid signature) during the current round, will enter a new round on determining the end of the current round or at any time on receiving a round initializing command. The Transponders will select a slot at random and transmit in the new round when the slot counter value and the slot selected are equal.

If at any time the Transponder receives a wake_up (FST) command whether in the READY state or in the ISO ROUND_ACTIVE or ROUND_STANDBY states, it will immediately switch to the FST mode of operation.

FST SYSTEMS

In the absence of an RF field, the Transponders are in the RF_field_off state. When the Transponders enter the energizing field of a Reader, they go through a power on reset sequence. If the FST bit = 0 and the WUS bit = 0, then the Transponder moves to the ROUND_ACTIVE State it is therefore in a Tag Talks First mode and commences a Fast Supertag

 collision arbitration

sequence. If the FST bit = 0 and the WUS bit = 1, then the Transponder moves to the ROUND_STANDBY state until it receives a Next_Slot, Close_Slot, New_Round or Wake_up_FST command, at which time it commences a Fast Supertag

 collision arbitration sequence.

detected

25 www.emmicroelectronic.com

Each slot has a duration at least as long as the duration of a Transponder preamble. The actual duration of the slot is determined by the Transponder and is equal to 16 Transponder bit times. If a Transponder has selected the current slot in which to transmit its reply, the Slot length is increased for that Transponder to the duration of a message length so that the Transponder can send its complete message. In order to prevent other tags (those that have not yet started their replies) from transmitting during the first tag’s reply slot the Reader issues a MUTE command to place the tags into the ROUND_STANDBY state. After the active Transponder has finished transmitting its message, and if the Reader has successfully read the Transponder it issues a Next_Slot command synchronously with the tag’s signature. If the Transponder message was not successfully read then the Reader issues a Close_Slot command, which will cause all the tags currently in the ROUND_STANDBY state to re-enter the ROUND_ACTIVE state.

The number of slots in a round, referred to as round size, is determined by the Reader and is signaled to the Transponder in the Wake_Up_FST or New_Round command. In the FST mode the tag elects a default roundsize of 16, which may be overridden by a Reader command, however the FST mode is able to operate without any round initializing command. During the subsequent collision arbitration process the Reader dynamically chooses an optimum round size for the following rounds based on the number of collisions and/or unproductive time in a round. The number of collisions is a function of the number of Transponders in the ROUND_ACTIVE state present in the Reader field and the current round size. The Reader signals a change in round size to Transponders by sending a New_Round command containing the required round size.

The Transponder on entering the ROUND_ACTIVE State or on re-entering the ROUND_ACTIVE state having completed a round, selects a pseudo slot at random in which to reply. Pseudo slots are equal to Transponder preamble in duration. If the Transponder has selected the first pseudo slot, it will transmit immediately, if not it will hold off until it has reached the selected pseudo-slot and then transmit.

On receiving and recognizing a valid Transponder transmission preamble, the Reader sends a MUTE command (SOF), which tells all Transponders that have not yet started transmitting, to move to the ROUND_STANDBY state. When the Reader receives the Transponder Next_Slot command containing the signature of the Transponder that it has just received.

Reply without error, it sends a

EM4223

Transponders in the ROUND_STANDBY state will go through an internal time-out sequence and will return to the ROUND_ACTIVE state after a period equal to 2.5 X 176 tag bit periods has elapsed since the last MUTE command if the WUS bit = 0 (this time-out may be overridden by the Transponder receiving further Standby_Round or MUTE commands from the Reader which keep the Transponder in the ROUND_STANDBY state). The Transponder will move to the ROUND_ACTIVE state before the end of time-out period if it receives a Next_Slot, Close_Slot, New_Round or Wake_Up_FST command.

When the Transponder has reached the end of a round, it will self-trigger a new round, randomly select a new slot in which to transmit and it will transmit its identity or data when it reaches the selected slot. The process continues until the Transponder has been successfully read and acknowledged by a valid Next_Slot command or removed from the RF energizing field.

If at any time the Transponder receives an Init_Round, Init_Round_All or Begin_Round command whether in the READY, ROUND_ACTIVE or ROUND_STANDBY states, it will immediately switch to the ISO mode of operation.

BOTH TYPES – READ ACKNOWLEDGE

When a Transponder which has transmitted its data in the current slot, receives a Next_slot command, it:

 Verifies that the signature in the command matches

the signature it sent in its last

 Verifies that the Next_Slot command has been

received within the timing window. If the Transponder has met these acknowledge conditions it enters the Quiet state. Otherwise, it remains in the ROUND_ACTIVE state.

A Transponder in the Quiet state can only be returned to the active population by means of a Reset_To_Ready command followed by the appropriate round initializing command or by removing it from the RF energizing field for longer than the persistent sleep time.

FST MODE OPTIONS

If the FST = 0 set and the WUS = 1, the Transponder will wake up in Tag Talks First mode but muted. The first Next_Slot command will move the Transponder to the ROUND_ACTIVE state and it will enter a round as if it had received a Wake_Up command.

If both the WUS = 0 and FST = 0 the Transponder will move directly to the ROUND_ACTIVE state as if it had received a Wake_Up command.

26 www.emmicroelectronic.com

Use of the round_size function (ISO & FST modes)

To optimized the system for the Transponder population size, the Reader is able to send round size commands to the Transponder by way of INIT_ROUND, INIT_ROUND_ALL, BEGIN_ROUND, NEW_ROUND and WAKE_UP_FST commands. The Reader needs to determine the proportion of collisions occurring and the amount of white space occurring and accordingly adjust the round size. As collisions increase proportional to the

Bit coding Value

MSB LSB

'0' 0 0 0 1

'1' 0 0 1 8

'2' 0 1 0 16

'3' 0 1 1 32

'4' 1 0 0 64

'5' 1 0 1 128

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number of successful reads, the round size should be increased. As the proportion of white space increases in proportion to the number of successful reads the round size should be decreased.

The round size is coded in the INIT_ROUND, INIT_ROUND_ALL, BEGIN_ROUND, NEW_ROUND and WAKE_UP_FST commands using 3 bits according to

74H74HTable20.

Round Size

'6' 1 1 0 256

'7' 1 1 1 RFU

Table20 - Round size coding

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Pad Location Diagram

all dimensions in Microns

V DD

X=388, Y= 511

EM4223

A X= 0, Y= 0

X = - 142 Y = - 159

Chip size is X= 1012 by Y= 830 microns Note: The origin (0,0) is the lower felt coordinate of center pads The lower left corner of the chip shows distances of origin

Pin # Name Position x Position y

1 2 3

Position is given in μm from the Seal Ring.

SOT 23 package outline

A+ 200 120 V

700 120

VDD 450 550

Table 21 - Connection Pad Positioning

EM4223

V SS X=735, Y= 0

Fig. 20

NOTES: y D&E do not include mold flash

y Mold flash or protrusions not to

exceed .15mm (.006")

y Controlling dimension: millimeter



Dim Min [mm] Max [mm]

A 0.787 1.194

A1 0.025 0.127

B 0.356 0.559

C 0.086 0.152

D 2.667 3.048

E 1.194 1.398

e 1.778 2.032

H 2.083 2.489

L 0.102 0.305

S 0.432 0.559  0° 8°

Fig. 21

28 www.emmicroelectronic.com

(

)

SOT 23 pinout

Pad A

EM4223

Pad VSS

Fig. 22

Ordering Information

Packaged Device: Device in DIE Form:

EM4223 EM4223

ersion

"Personality word" "Personality word" Check table below Check table below

e Die form

Packa

SP3B = 3-

in SOT23, WW = Wafer

in Tape&Reel of 3000 pieces WS = Sawn Wafer/Frame

11V% SP3B V% WS

ersion

Thickness

7 = 7 mils (158um) 11 = 11 mils

280um

EM4223

Bumping

" " (blank) = no bump

Versions (Personality word)

Personality

word

Return link

data rate

E = with gold bumps

FST / ISO Flag Wake Up Status Flag

V8 160 Kbps ISO V7 160 Kbps ISO ISO_MOD V6 160 Kbps FST RTF V5 160 Kbps FST TTF V4 40 Kbps ISO V3 40 Kbps ISO ISO_MOD V2 40 Kbps FST RTF V1 40 Kbps FST TTF

Table 22

Standard Versions:

The versions below are considered standards and should be readily available. For the other delivery form, please contact EM Microelectronic-Marin S.A. Please make sure to give the complete part number when ordering.

Part Number Package/Die Form Delivery form/Bumping EM4223V2SP3B EM4223V3SP3B EM4223V2WS11E EM4223V3WS11E

EM Microelectronic-Marin SA (EM) makes no warranty for the use of its products, other than those expressly contained in the Company's standard warranty which is detailed in EM's General Terms of Sale located on the Company's web site. EM assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of EM are granted in connection with the sale of EM products, expressly or by implications. EM's products are not authorized for use as components in life support devices or systems.

SOT 23 Tape & reel SOT 23 Tape & reel Die 11 mils Sawn on frame / Bump Die 11 mils Sawn on frame / Bump

Table 23

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EM MICROELECTRONIC EM4223 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Table of contents

1. GENERAL DESCRIPTION

2. FUNCTIONAL DESCRIPTION

3. BASIC COMMAND FORMATS

4. GENERAL REPLY FORMAT

5. FORWARD LINK ENCODING - READER TO TRANSPONDER

6. RETURN LINK DATA ENCODING - TRANSPORTER TO READER

7. MEMORY ORGANISATION AND CONFIGURATION INFORMATION

8. TRANSPONDER SELECTION OPERATION – INIT_ROUND AND BEGIN_ROUND COMMANDS

9. COMMANDS AND STATES

10. COLLISION ARBITRATION