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LFMICROEVALKIT
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Texas Instruments LFMICROEVALKIT User Manual

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May ’00 Preface
Series 2000 Reader System
Micro-reader RI-STU-MRD1
Reference Guide
11-06-21-027 May 2000
1
Edition Three - May 2000
This is the third edition of this manual, it describes the following equipment:
TIRIS Micro-reader Module
Texas Instruments (TI) reserves the right to make changes to its products or services or to discontinue any p roduc t o r se rvi ce at a ny ti me with out not ic e. T I prov id es cu s­tomer assistance i n various technic al areas, but do es not have full ac cess to data concerning the use and applications of customer's products.
Therefore, TI assumes no liability and is not responsible for customer applications or product or software design or performance relating to systems or applications incor­porating TI produ cts. In addi tion, TI assu mes no liab ility and i s not respons ible for infringement of patents and/or any other intell ectual or industrial proper ty rights of third parties, which may result from assistance provided by TI.
TI products are not designed, intended, authorized or warranted to be suitable for life support applications or a ny othe r li fe cr iti ca l appl ic ati on s wh ic h cou ld inv ol v e po ten­tial risk of death, personal injury or severe property or environmental damage.
RI-STU-MRD1
The Incorporated.
Copyright 2000 Texas Instruments Incorporated (TI) This document may be downloaded onto a computer, stored and duplicated as nec-
essary to support the us e of the related TI products. Any othe r type of duplicatio n, circulation or storage on data carriers in any manner not authorized by TI represents a violation of the applicable copyright laws and shall be prosecuted.
logo and the word
TIRIS
are registered trademarks of Texas Instruments
TIRIS
2
About This Guide
Conventions
PREFACE
Read This First
This manual describes the TIRIS Micro-reader, its goal is to describe the reader, how it works, how to integrate it and how to use it.
WARNING:
A
WARNING IS USED WHERE CARE MUST BE TAKEN, OR A CERTAIN
PROCEDURE
TO
HARM
CAUTION:
MUST BE FOLLOWED IN ORDER TO PREVENT INJURY OR
YOUR HEALTH
.
If You Need Assistance
Application Centers are located in Europe, North and S outh Amer ica, the Far E ast and Australia to provide direct su pport. For more information, please contact your nearest TIRIS Sales and Application Center. The contact addresses can be found on our home page:
This indicates information on conditions which must be met, or a procedure which must be followed, which if not heeded could cause permanent damage to the equipment or software.
Note:
Indicates conditions which must be met, or procedures which must be followed, to ensure proper functioning of the equipment or software.
Information:
Indicates information which makes usage of the equipment or soft­ware easier
http://www.tiris.com
3
Document Overview
Page
Chapter 1: Product Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 General............................................................................................... 6
1.2 Product Description....................................... ...... ....... ...... ....... ........... 6
1.3 Connector Pins................................................................................... 9
Chapter 2: Communications Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.1 Protocol PC to Micro-reader............................................................. 15
2.2 Protocol Micro-reader to PC............................................................. 18
Chapter 3: Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.1 Recommended Operating Conditions .............................................. 21
3.2 Timings............................................................................................. 22
3.3 Mechanical Data............................................................................... 22
Chapter 4: Transponder Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1 Transponder commands .................................................................. 24
4.2 Transponder Responses.................................................................. 27
Chapter 5: Communication Protocol Examples . . . . . . . . . . . . . . . . . . . . . . . 29
5.1 PC to Micro-reader........................................................................... 30
5.1 PC to Micro-reader........................................................................... 30
Appendix A:CE Declaration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Appendix B:Demonstration Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Appendix C:Antenna Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
List of Figures
Figure 1: Micro-reader Module....................................................................... 6
Figure 2: Micro-reader Pin Connections ........................................................ 9
Figure 3: Block Diagram of the Micro-reader ............................................... 12
Figure 4: Antenna Circuit Block Diagram..................................................... 13
Figure 5: Top, Front and Side View (measurements in mm) ....................... 22
Figure 6: Read Function............................................................................... 24
Figure 7: Programming Data Format of the 64-bit Read/Write Transponder24
Figure 8: Data Format of the General Read Page Function ........................ 25
Figure 9: Programming Data Format of the MPT......................................... 25
Figure 10: Lock Page of MPT/SAMPT......................................................... 25
Figure 11: Data Format of the Selective Read Page Function..................... 26
Figure 12: Data Format of the Selective Program Page Function ............... 26
Figure 13: Data format of the Selective Lock Page function........................ 26
Figure 14: RO Read Data Format................................................................ 27
Figure 15: R/W Read Data Format .............................................................. 27
Figure 16: MPT/SAMPT Read Data Format ................................................ 27
Figure 17: Micro-reader Demonstration Circuit ............................................ 36
Page
List of Tables
Table 1: Pin Connections ............................................................................... 9
4
Page
Chapter 1: Product Description
This chapter describes the hardware of the Micro-reader. It tells you about the mod­ule and how to integrate it.
Topic Page
1.1 General..........................................................................................................6
1.2 Product Description.....................................................................................6
1.2.1 Power Supply.........................................................................................7
1.2.2 Antenna..................................................................................................7
1.2.3 Synchronization......................................................................................7
1.2.4 Trigger Mode..........................................................................................8
1.2.5 Continuous Mode...................................................................................8
1.2.6 Serial Communication ............................................................................8
CHAPTER 1
Product Description
1.3 Connector Pins.............................................................................................9
1.3.1 Pin Connection Description........................................................... ...... .1 0
1.3.2 Module and Antenna Block Diagrams..................................................12
5
1.1 General
The Micro-reader is an intelligent module providing RF and Control functions to read and program TIRIS transponders. It is equipped with a Serial Communications Inter­face (SCI) which may be directly connected to commonly use d system controlle rs. The Micro-reader works together with a 47 µHenry, low-Q antenna, and therefore the system does not need tuning.
Figure 1: Micro-reader Module
1.2 Product Description
The Micro-reader module is a plug-in module which can be plugged into or soldered onto an applicat ion specific adapte r board. It suppor ts serial data com munications between a PC and TIRIS transpo nders. With its Serial Communications Int erface (SCI) the Micro-reader supp orts TTL data com munications, which with the addition of a communications driver (for example: RS232 or RS422) allows communication to a standard interface.
The Micro-reader can be controlled remotel y by either provid ing certain inpu ts with the correspondin g voltage leve l or sending co mmands to the S CI. It can be dri ven either with or without synchronization - the synchronization can be either wireless or wired to enable reli able operation in mu lti-reader envir onments. Two outputs show the reader status and inform th e user about a successf ul comman d execution. The Micro-reader supports all available TIRIS LF transponders.
6
May ’00 Chapter 1. Product Description
1.2.1 Power Supply
There are two separa te 5V supplies to the Micro-reader , one for the output stage (VSP) and the other for the logic (VSL). On power up VSL should rise faster than 0.1 V/ms to ensure a r eliab le operation. The Micro- reader has an on-boa rd res et ci r cuit which will reset it should the supply fall below 4 V (± 0.2 V).
In order to avoid problems with noise conducted via the supply lines, we recommend that if a single supply is used, separate connections from a common de-coupling ca­pacitor are used to feed the Micro-reader.
Note:
The RF Module must not be supplied by Switched Mode Power Sup­plies (SMPS). This is because most SMPS operate at frequencies around 50 kHz. The harmonics of the generated field can interfere with the TIRIS receiver. Therefore only use linear regulated power supplies, or SMPS with a fundamental operating frequency of 200 kHz or higher.
1.2.2 Antenna
The Micro-reader has been designed for use with a 47 µH antenna with a Q of 10 to 20 to generate the exciter frequency of 134.2 kHz. Because of the low Q the system does not need to be tuned.
1.2.3 Synchronization
There are two possible methods of wired synchronization:
1. Connect a pulse waveform to all RDEN- input pins of the Micro-readers to be
2. Connect all SYNC outputs to an 'Or' and then connect this as an input to RDEN-
Wireless synchronization of the Micro-reader is very effective at synchronizing to ad­jacent readers, however problems may occur if the antennas are positioned such that a transponder can be within rang e of two reade rs at the same ti me. In this situ ation one reader could synchronize with the transponder instead of the other reader.
When the WLSC input is active the Micro-reader is in wireless synchronization mode. Wireless synchronization can also be switched on/off by a corresponding command via the serial interface. During execution of this command it has priority over the WLSC input. After the command execution the status of the WLSC input will be con­sidered again.
WARNING:
C
ARE MUST BE TAKEN WHEN HANDLING THE MICRO-READER AS
HIGH
VOLTAGES ACROSS THE ANTENNA PINS COULD BE HARMFUL
YOUR HEALTH
TO
synchronized. The pulse would normally be at VSL, dropping to GND for 100 µs every 200 ms.
of each Micro-reader to be synchronized.
.
7
Note:
It is not recommended to have both wired and wireless synchroniza­tion switched on as synchronization could be unreliable.
We recommend the use of bus drivers for wired synchronization with other Micro-readers and to prevent ESD damage.
Wired or wirele ss syn ch ron iza ti on pr ol o ngs t h e cy cl e ti me by typically 20 ms.
1.2.4 Trigger Mode
When the Micro-reade r is in idle mode it i s possible to trigge r a single charge-o nly read with a power burs t duratio n of 50 ms by taking th e RDEN- pi n to lo gic h igh for 100 µs. The single read will start on the falling edge of the 100 µs pulse.
If a transponder command is sent to th e Micr o-re ade r via the SCI while RDEN- is in a logic high state (waiting position), a falling edge would trigger execution of the com­mand. In waiting position the Micro-reader can only store one command. This means that if two commands were to be sent to the Micro-reader while it is in the waiting po­sition the second command will overwrite the first one.
1.2.5 Continuous Mode
When the CRDM input is active th e Micro-re ader goes i nto continuo us charge-o nly read mode using a power burst duration of 50 ms. The serial data input takes priority over the CRDM input such that if a serial co mmand is received it will be executed regardless of the state of the CRDM input. After the execution of the serial data com­mand the Micro-reader conti nue s with the prev iou s read mode .
In the default continuous read mode, only those valid RO, R/W or MPT IDs that differ from the previously read ID; or valid IDs read after a “NO READ”, are transferred via the SCI (Normal Mode). The Micro-reader can be set to transfer all valid IDs that are read (Line Mode) by means of a corresponding serial data command.
Without synchronizati on the Micr o -rea der has a readi ng frequ enc y of appro ximately 10 readouts per se cond using a power bur st duration of 50 ms . Timing is given in more detail in section 3.2.
1.2.6 Serial Communication
The two serial I/O pins are configured for 9600 Baud, 1 start bit, 8 data bits, no parity and 1 stop bit; they can be connected directly to a communications driver to allow a half duplex communication with a PC via its serial communications interface (for ex­ample: RS232 or RS422).
The communications protocol is specified in Chapter 2.
Handshake
The Micro-reader accepts handshak e commands X (13
) the Micro-reade r stops its current ope ration and stops tran smitting da ta via
hex
the serial port. It stays in idle mode until X the previous mode/command. During this idle period the Micro-reader accepts com­mands via the seri al port, howeve r, it w aits fo r its ex ecuti on unti l X this idle period the Micro-reader can store only one command.
on
. When it receiv es a n X
on/Xoff
(11
) is received when it co ntinues w ith
hex
on
off
is received. In
8
May ’00 Chapter 1. Product Description
Note:
While receiving a command protocol from the serial port X
on/Xoff
is
interpreted a s no rmal da t a wit h ou t a ffecting t h e s eri al co mm u n ic at i on .
1.3 Connector Pins
The Micro-reader module h as 30 pin connecti ons which a re shown in Figure 2 and listed in Table 1.
Figure 2: Micro-reader Pin Connections
Table 1: Pin Connections
Pin Signal Name Function
1 SYNC Output for wired synchronization 2 RDEN- Input for wired synchronization and single read trigger 3 -- Reserved, do not connect 4 RESET- Reset of the Micro-reader 5 RXD Receive Data signal input of serial interface
6 TXD Transmit Data signal output of serial interface 7 -- Reserved, do not connect 8 -- Reserved, do not connect
9 -- Reserved, do not connect 10 -- Reserved, do not connect 11 -- Reserved, do not connect 12 -- Reserved, do not connect 13 -- Reserved, do not connect
9
Micro-reader - Reference Guide May ’00
Table 1: Pin Connections
Pin Signal Name Function
14 -- Reserved, do not connect 15 GND Ground for logic
16 ANT1 Antenna terminal 1 17 ANTCAP Antenna capacitor terminal 18 -- Reserved, do not connect
19 ANT2 Antenna terminal 2
20 21 22 23 24 25 26 27 28 29 30
1.3.1 Pin Connection Description
SYNC (1) Output for wired synchronization. This output is at GND level until
-- Reserved, do not connect
GNDP Ground for output stage
VSP Supply voltage output stage
-- Reserved, do not connect
VSL Supply voltage logic GND Ground for logic CRD Input for continuous read mode WLS Input to swit ch wireless synchronization on
-- Reserved, do not connect
OKT Output to show if a valid ID was read
STAT Output to show status of RF-transmitte r control signal
the Micro-reader starts its read cycle, at which time it goes to VSL until the complete reading, programming or locking cycle is finished.
RDEN- (2) Input for wired synchronization. Taking this pin to VSL acts as a
hold-off for the Micro-reader's output stage preventing it from transmitting until the input returns to GND. The Micro-reader only samples this input at the start of its own reading, programming or locking cycle, this means that if the input goes to VSL after a cycle is started, the cycle is not interrupted. RDEN is a high impedance input and must be tied to GND via a suitable resistor (27 kOhm) when it is not being used.
When the Micro-reader is idle it is possible to trigger a single read by taking the RDEN-pin logic high for 100 ms. The single read will start on the falling edge of the 100 ms pulse.
RESET- (4) Taking this pin to GND holds the Micro-reader in reset. If the reset
pin is not used it can be left disconnected as it is internally pulled up. Minimum pulse duration to perform a reset is 1 ms. After a reset the
10
May ’00 Chapter 1. Product Description
processor takes between 28 ms and 132 ms (typically 72 ms) before it can receive new instructions via the serial communications interface.
RXD (5) Input configured to receive serial data commands at 9600 Baud, 1
start bit, 8 data bits, no parity and 1 stop bit.
TXD (6) Output configured to transmit serial data at 9600 Baud, 1 start bit, 8
data bits, no parity and 1 stop bit. GND (15, 25) Pins 15 and 25 are ground for the logic part. ANT1 (16) Antenna pin for the connection of 47 µH, low Q antennas. ANTCAP (17) It is possible to use antennas of lower inductance by connecting a
suitable capacitor between ANT1 and ANTCAP. This additional
capacitor (ceramic, 100 VDC) will be in parallel with the 30 nf
resonance capacitor on board the Micro-reader (see Figure 4 and
Appendix C). ANT2 (19) Antenna pin (GND) for the connection of 47 µH, low Q antennas. GNDP (21) Pin 21 is ground for the output stage. VSP (22) Pin 22 is for connecting the positive supply voltage (5 V) for the
output stage. VSL (24) Pin 24 is for connecting the positive supply voltage (5 V) for the logic
part. CRDM (26) Supplying pin 26 with a logic high signal causes the Micro-reader to
run in a continuous charge-only read mode (see section 1.2.5
more information).
When the CRDM pin is tied to logic low, the Micro-reader is in an idle
state waiting for commands via the serial interface or for a trigger
signal (RDEN-) to start a single read out cycle. CRDM is a high
impedance input and must be tied to either VSL or GND via a
suitable resistor (27 kOhm). WLSC (27) Pin 27 enables or disables wireless synchronization. To enable the
wireless synchronization, pin 27 must be taken to VSL. When
wireless synchronization is enabled, the Micro-reader will try to
synchronize its transmit signals with any other readers in range. To
disable wireless synchronization pin 27 must be taken to GND. Pin
27 is a high impedance input and must be tied to either VSL or GND
via a suitable resistor (27 kOhm).
Wireless synchronization can also be switched on/off by a
corresponding command via the serial interface. During execution of
this command it has priority over the WLSC input. OKT (29) This output is set to logic high for approx. 60 ms if a valid
transponder was read. It can be connected to an LED externally to
indicate the result of the read cycle.
for
STAT(30) Pin 30 is set to logic low when the RF-transmitter is activated.
Supplying an external LED with this signal makes the status of the
Micro-reader visible.
11
Micro-reader - Reference Guide May ’00
1.3.2 Module and Antenna Block Diagrams
Figure 3: Block Diagram of the Micro-reader
VSL
RESET­CRDM WLSC RDEN-
MICRO
CONTROLLER
SYNC OKT STAT TXD RXD
RXCK RXDT­TXCT-
RFM
ASIC
Filter
VSL
VSP
Power
stage
GND
VSL
VSP GNDP
ANT1
ANT2
ANTCAP
12
May ’00 Chapter 1. Product Description
Figure 4: Antenna Circuit Block Diagram
RECEIVE
VSP
TXHI from ASIC
TXLO from ASIC
RESONANCE CAPACITOR
ANT1
ANT2
ANTCAP
13
Communications Protocol
Chapter 2: Communications Protocol
This chapter desc ribes the protocol that you need to use to send ins tructions from your PC to the micro-reader. It also describes the protocol that the micro-reader uses to respond to the PC.
Topic Page
2.1 Protocol PC to Micro-reader .....................................................................15
2.1.1 Start Mark.............................................................................................15
2.1.2 Length ..................................................................................................15
2.1.3 Command Field....................................................................................16
2.1.4 Data Field.............................................................................................17
2.1.5 BCC......................................................................................................18
CHAPTER 2
2.2 Protocol Micro-reader to PC .....................................................................18
2.2.1 Start Mark.............................................................................................18
2.2.2 Length ..................................................................................................18
2.2.3 Status...................................................................................................19
2.2.4 Data Field.............................................................................................19
2.2.5 BCC......................................................................................................19
14
May ’00 Chapter 2. Communications Protocol
2.1 Protocol PC to Micro-reader
2.1.1 Start Mark
Start Length
Byte Contents (hexadecimal value)
0 Start Mark (SOH , 01 1 Length 2 Command Field (1) 3 Command Field (2) (optional) 4(3) Data Field (1) . . N+3(2) Data Field (N) N+4(3) BCC
Examples are given in section 5.1.
Cmd 1 Cmd 2 Data
Note:
The total number of bytes sent within a protocol frame (including Start Mark and BCC) is limited to 41 bytes.
hex
BCC
)
2.1.2 Length
The 'Start-Mark' signifies the beginning of a message. It is represented by the ASCII character SOH (Start Of Header, 01
The 'Length' byte indicates the length, in bytes, of the following Command and Data Fields.
hex
).
15
Micro-reader - Reference Guide May ’00
2.1.3 Command Field
The 'Command Field(s)' defines the mod e in which the Micro-reader operates and determines the operation th at is to be c arried out in the trans ponder . Depend ing on the setting of the relev ant bits, the correspo nding information s pecified in the Data Fields will be sent to the transponder or not. Thus all functions of each particular tran­sponder type can be executed (see 2.1.4 for further information).
Command Field (1)
Bit Use Setting Comment
0/1 Mode/Cmd 00 Perform single command
(MSB,LSB) (for example: single read, program, lock)
01 Read in contin uou s Normal Mode 10 Read in contin uou s Lin e Mode 11 Send Micro-reader S/W version
2 FBCC calculation 1/0 If set, Micro-reader calculates FBCC of the
MPT protocol
3 Power Burst I 1/0 If set, needs to be determined in Data Field
(see 2.1.4) 4 Power Pause Duration 1/0 If set, needs to be determined in Data Field 5 Power Burst II 1/0 If set, needs to be determined in Data Field 6 Data 1/0 If set, needs to be determined in Data Field 7 Cmd expansion Field 1/0 If set, Command Field (2) follows
If bit 5 (Power Burst II, for exa mple: fo r programm ing and locking ) is set, th e Micro­reader automaticall y operates in single mo de. Thus the user is enabled to validate the programming or lock response before a further cycle is started.
If bit 2 (FBCC calculation) and bit 6 (Data) are set, the Micro-reader automatically cal­culates a two byte BCC over the data to be sent to the transponder and adds it to the protocol. When bits 2 and 6 are set the PC must n ot send the 2 byte FBCC to th e Micro-reader.
Bit 4 (Power Pause Duration) is for future use and must not be set when addressing standard TIRIS transponders.
Example:
E8
= 1110 1000
Hex
1 1 1 0 1 0 0 0
BIN
Perform single command No FBCC calcul ation Power burst I v a lu e set in Data Field Default set to 0 Power burst II value set in Data Field Data values follows in Data Field Command Field (2) follows
16
May ’00 Chapter 2. Communications Protocol
Command Field (2)
Command Field (2) is only present if bit 7 of Command Byte 1 is set.
Bit Use Setting Comment
0 Special Write Timing 1/0 If set, needs to be determined in Data Field
(see 2.1.4) 1 Wireless Synchronization 1/0 If set, wireless synchronization is used 2 DBCC calculation 1/0 If set, Micro-reader calculates DBCC of the
R/W and MPT write data 3-7 Reserved
2.1.4 Data Field
Example:
06
= 0000 0110
Hex
0 0 0 0 0 1 1 0
BIN
No Special Write Timing Wireless Synchronization is used Micro-reader ca lc ulates DBCC Bits 3-7 reserve d
If Command Field (2) is not present, standard TIRIS write timings are used and wire­less synchronization is switched on/off according to the status of input line WLSC.
Note:
The settings specified in Command Field (1) and (2) are only valid during the execution of the current command.
The presence of the relevant data field depends on the setting of the bits in the Com­mand Field.
If the relevant bit (for example: Command bit 3 “Power Burst I”) is set to “1”, then Data Field 1 is present defining the Power Burst length. If the relevant bit in the Command Field is set to “0 ” the cons equent Data Fiel d is omitte d, this resul ts in the fo llowing data field being moved forward (decremented) by one.
Data Field Use Range (dec) Comment
1 Power Burst I 1..255 ms If bit 3 of Command Field(1) is set 2 Power Pause Duration 1..255 ms If bit 4 of Command Field(1) is set
3 Power Burst II 1..255 ms If bit 5 of Command Field(1) is set 4/5 toffLow (LSByte/MSByte) 28..2044 ms If bit 0 of Command Field(2) is set 6/7 tonLow (LSByte/MSByte) 28..2044 ms If bit 0 of Command Field(2) is set 8/9 toffHigh (LSByte/MSByte) 28..2044 ms If bit 0 of Command Field(2) is set
10/11 tonHigh (LSByte/MSByte) 28..2044 ms If bit 0 of Command Field(2) is set
12 # of Data Fields that follow see * If bit 6 of Command Field(1) is set
13 . . Data Fields LSByte first
* The n umber of Data Fi elds m ust no t cause an inf ringemen t of the to tal num ber
of bytes allowed within a protocol frame.
Transponder command protocols are described in detail in section 4.1.
17
Micro-reader - Reference Guide May ’00
2.1.5 BCC
The 'BCC' field is a one -byte valu e of the L ongitudin al Redundan cy Check calcula­tion (Xor'ed bytes) for the preced ing message. The cal culation is perfor med on the whole message excluding the Start-Mark.
Example:
02 08 32
02 0000 0010 08 0000 1000
--------------------------------
XOR 0000 1010 32 0011 0010
--------------------------------
XOR 0011 1000 = 38 (hex)
2.2 Protocol Micro-reader to PC
Start
Length
Byte Contents (hexadecimal value)
0 Start Mark (SOH, 01 1 Length 2Status 3 Data Field (1) (LSByte)
. .
. N+2 Data Field (N) (MSByte) N+3 BCC
hex
BCCStatus Data
)
2.2.1 Start Mark
2.2.2 Length
Refer to section 5.2 for examples.
The 'Start-Mark' signifies the beginning of a message. It is represented by the ASCII character SOH (Start Of Header: 01
The 'Length' byte indicate s the length, in bytes, of the following Statu s and Data Fields.
hex
)
18
May ’00 Chapter 2. Communications Protocol
2.2.3 Status
The 'Status' byte provides feedback from the preceding read or program operation.
Status Bits Setting Comment
0,1 00 Transponder type: RO
(MSB,LSB)
01 Transponder type: R/W 10 Transponder type: MPT/SAMPT
11 Other 2 1/0 If set, Startbyte detected 3 1/0 If set, DBCC O.K. 4 1/0 If set, FBCC O.K. 5 1/0 If set, Micro-reader S/W version follows
6 - 7 Reserved
2.2.4 Data Field
Response # of Bytes
Type in Data Field Comment
RO 8 Identification Data (LSByte first), 4.2.1
2.2.5 BCC
R/W 8 Identification Data (LSByte first)), 4.2.2
MPT/SAMPT 9 Identifi cation Data (L SByte firs t), plus Read Add ress, see
4.2.3
Other 14 Complete transp onder protocol without pre-bits provided
that a valid RO or R/W start byte was detected
No read 0 No Da ta Fields, not even tr ansponder start byte w as de-
tected, status 03
S/W version 1 For example: 15
Section 4.2 transponder types.
The 'BCC' field is a one -byte valu e of the L ongitudin al Redundan cy Check calcula­tion (Xor'ed bytes) for the preced ing message. The cal culation is perfor med on the whole message excluding the Start-Mark. An example is shown in section 2.1.5.
provides an overview of the response telegrams of the current TIRIS
hex
means S/W version 1.5
hex
19
Chapter 3: Specifications
This chapter provides the specifications for the micro-reader, its inputs and outputs, and its timing.
Topic Page
3.1 Recommended Operating Conditions......................................................21
3.2 Timings .......................................................................................................22
3.3 Mechanical Data.........................................................................................22
CHAPTER 3
Specifications
20
May ’00 Chapter 3. Specifications
3.1 Recommended Operating Conditions
Operating free-air temperature range T_oper -25 to +70 ºC Storage temperature range T_store -40 to +85 ºC
Note:
Free-air temperature: air temperature immediately surrounding the Module. If the module is incorporated into a housing, it must be guar­anteed by proper design or cooling that the internal temperature does not exceed the absolute maximum ratings.
Symbol Parameter Min. Typ. Max. Unit
V_VSP Supply voltage for power stage 4.5 5.0 5.5 V V_VSL Supply voltage for logic 4.5 5.0 5.5 V
I_VSP Supply current for power stage ­I_VSL Supply current for logic -
I_su Output current sunk by an output pin - 5.0 15.0 mA I_so Output current sourced by an output pin - 5.0 15.0 mA
I_sutot Output current sunk by all outpu t pins - 20.0 60.0 mA
I_sotot
V_ret
Vrise_ret
I_idle Supply current with Micro-reader idle - 5.0 - mA
I_act Supply current with Micro-reader active -
ViH Input high voltage 0.8 VSL - VSL -
ViL Input low voltage GND - 0.2 VSL ­VoH Output high voltage VSL - 0.7 VSL VoL Output low voltage GND 0.6 V
I_sototOutput current so urc ed by all
output pins
VSP start voltage to guarantee power
on reset
VSP rise rate to guarantee power on
reset
-20.060.0mA
--GND-
0.1 - - V/ms
10 30
100
*1
*2
*3
-mA
-mA
-mA
Q_Ant Antenna quality factor 10 15 20
L_Ant Antenna inductance value 46.1 47.0 47.9
*1 Typical supply current (pe ak va lue ) for the power stage when the RF tr ans mi tter
is switched on (L = 47
µ
H, Q = 12). *2 Typical supply current for logic when the RF transmitter is switched on. *3 Typical supply current (average value) of the Micro-reader when the RF transmit-
ter is switched on (L = 47
µ
H, Q = 12).
21
H
µ
Micro-reader - Reference Guide May ’00
3.2 Timings
Parameter Typical Maxim Unit
Read Cycle time without sy nch (no read) 100 105 ms
3.3 Mechanical Data
Recommended finished pin hole size is 1 mm diameter.
Read Cycle time with synch (no read)
Read Cycle time without synch (valid read) 170 175 ms
Read Cycle time with synch (valid read) 190 245 ms
Interbyte time-out for serial communication
120 175 ms
*1
10
*1 If an Interbyte time-out occurs the Micro-reader performs a reset.
Parameter Minimum Typical Maximum Unit
Length 37.9 38.3 38.7 mm
Width 28.8 29.3 29.6 mm
Height including pins 12.5 13.5 14.0 mm
Weight 5.0 Grams
ms
Figure 5: Top, Front and Side View (measurements in mm)
22
Chapter 4: Transponder Protocols
This chapter describes the protocols used when sending commands to the transpon­der and the protocols used by the transponder when responding.
Topic Page
4.1 Transponder commands ...........................................................................24
4.1.1 Read RO, R/W .....................................................................................24
4.1.2 Program R/W ......................................... ...... ....... ...... ....... ...... ....... ...... .2 4
4.1.3 Addressing MPTs/SAMPTs..................................................................24
4.1.3.1 General Read Page of MPT/SAMPT..........................................25
4.1.3.2 Program Page of MPT/SAMPT...................................................25
4.1.3.3 Lock Page of MPT/SAMPT.........................................................25
4.1.3.4 Selective Read Page of SAMPT.................................................26
4.1.3.5 Selective Program Page of SAMPT............................................26
4.1.3.6 Selective Lock Page of SAMPT..................................................26
CHAPTER 4
Transponder Protocols
4.2 Transponder Responses...........................................................................27
4.2.1 Read Only Transponder.......................................................................27
4.2.2 Read/Write Transponder......................................................................27
4.2.3 MPT/SAMPT ........................................................................................27
23
Micro-reader - Reference Guide May ’00
4.1 Transponder commands
This section describes the protocols that need to be sent by the PC to the transpon­der via the Micro-reader in order to execute the required function.
4.1.1 Read RO, R/W
Figure 6: Read Function
OFF
RF TRANSMITTER
ON
4.1.2 Program R/W
Figure 7: Programming Data Format of the 64-bit Read/Write Transponder
OFF
RF TRANSMITTER
ON
PO W ER BU RST I
50 ms
8
WRITE
KEYWORD
16 ms 160 ms 32 ms
LSB MSB
Write Keyword : BB
Write Password : EB
Write Frame : 0300
4.1.3 Addressing MPTs/SAMPTs
POWER BURST
50 ms 20 ms
112 bit
8
WRITE WRITE
PASSWORD
16 ms
80 16
WRITE DATA
309 ms
hex hex
hex
FRAME
READ
PB II
15 ms
128 bit
READ
20 ms
Since MPT/SAMPTs allo w the execution of the differ ent commands applicable to multiple pages the 'Write Address' needs to be sent within the protocol in order to de­termine the function to be executed with a specific MPT/SAMPT page.
WRITE ADDRESS
MSB LSB
P P P P P P C C
||
PAGE COMMAND
MSB LSB MSB LSB
Page 1 000001 00 General read page
Page 2 000010 01 Program page . . . 10 Lock page Page 16 010000 11 Selective read
Page 17 010001
24
May ’00 Chapter 4. Transponder Protocols
4.1.3.1 General R ead Page of MPT/SAMPT
Figure 8: Data Format of the General Read Page Function
RF TR ANSMITT ER
4.1.3.2 Program Page of MPT/SAMPT
Figure 9: Programming Data Format of the MPT
OFF
RF
TRANSMITTER
ON
POW ER B URST I
50 ms
880 16
WRITE
ADDRESS
16 ms 160 ms 32 ms
LSB
4.1.3.3 Lock Page of MPT/SAMPT
OFF
ON
WRITE DATA
8 bit 128 bit
POW ER BURST I
50 ms
86 ms
104 bit 128 bit
WRITE FRAME BCC
293 ms
ADDRESS
LSB
MSB
WRITE
PB II
15 ms
READ
20 ms16 ms
READ OR
DISCHARGE
20 ms
Figure 10: Lock Page of MPT/SAMPT
OFF
RF TRANSMITTER
ON
POWER BURST I
50 ms
LSB
8
WRITE
ADDRESS
16 ms
24 bit
16
WRITE FRAME BCC
32 ms
133 ms
MSB
PB II
15 ms
128 bit
READ OR
DISCHARGE
20 ms
25
Micro-reader - Reference Guide May ’00
4.1.3.4 Selective Read Page of SAMPT
Figure 11: Data Format of the Selective Read Page Function
OFF
RF TRANSMITTER
POWER BURST I
ON
50 ms
4.1.3.5 Selective Program Page of SAMPT
Figure 12: Data Format of the Selective Program Page Function
OFF
RF TRAN SMITTER
ON
PO W ER BURST I
50 ms
8
WRITE
ADDRESS
16 ms
LSB
4.1.3.6 Selective Lock Page of SAMPT
8
WRITE
ADDRESS
16 ms
8 - 32
SELECTIVE
ADDRESS
16 - 6 4 ms
16
WRITE FRAME BCC
32 ms
32 - 56 bit
LSB MSB
134 - 182 ms
112 - 136 bit
8 - 32
SELECTIVE
AD D RE S S
16 - 64 ms
80
WRITE FRAME BCCWRITE DATA
160 ms 32 ms
309 - 357 ms
16
PB II
15 ms
MSB
128 bit
READ OR
DISCHARGE
20 ms
128 bit
READ OR
DISCHARGE
20 ms
OFF
RF TRAN SMITTER
ON
Figure 13: Data format of the Selective Lock Page function
32 - 5 6 bit
8 - 32
SELECTIVE
AD D RE S S
16 - 64 ms
16
WRITE FRAME BCC
32 ms
149 - 197 ms
PO W ER BURST I
50 ms
8
WRITE
ADDRESS
16 ms
LSB
MSB
PB II
15 ms
128 bit
READ OR
DISCHARGE
20 ms
26
May ’00 Chapter 4. Transponder Protocols
E
4.2 Transponder Responses
This section shows the response telegrams of the current TIRIS transponder types.
4.2.1 Read Only Transponder
Figure 14: RO Read Data Format
PRE BITS
LSB
START
16 8
8
4.2.2 Read/Write Transponder
Figure 15: R/W Read Data Format
PR E BITS EN D BITS
LSB
START
16 8
8
4.2.3 MPT/SAMPT
Figure 16: MPT/SAMPT Read Data Format
START
PRE BITS
16
LSB
8
READ DATA
IDENTIFICATION DATA DATA BCC
64 16
112 bits
READ DATA
IDENTIFICATION DATA DATA BCC
64 16
11 2 bits 16 bits
READ DATA
IDENTIFICATION DATA
64
128 bit
STOP
DBCC
16
STOP
IDENT. DATA
READ
ADDR.
END BITS
16
16 bits
DISCHARGE
15
8
DISCHARGE
MSB
MSB
DISCHARG
FBCC
16
MSB
The Read Address c onsists of a 2-bit stat us fie ld and a 6- bit page field. The status field provides information about the function the multipage transponder has executed and the page field shows which page was affected.
READ ADDRESS
MSB LSB
P P P P P P C C
||
PAGE COMMAND
MSB LSB MSB LSB
Page 1 000001 00 Read unlocked page
Page 2 000010 01 Programming done . . . 10 Read locked page Page 16 010000 11 Reserved *
Page 17 010001
000000 00 Read unlocked page, locking not correctly executed 000000 01 Programming done, but possibly not reliable 000000 10 Read locked page, but locking possibly not reliable
27
Micro-reader - Reference Guide May ’00
*) If the status indicates 'Re se rved', the read data cannot be interpr et ed as ide ntifi-
cation data.
Note:
It is strongly recommended to verify whether the requested function has actually been carried out in the transponder by checking the Read Address. If a 'not reliable' response message is received, the com­mand must be sent again to guarantee transponder data retention.
28
Communication Protocol Examples
Chapter 5: Communication Protocol Examples
This chapter provides some examples of some actual commands sent to a transpon­der and some possible respo nse s.
Topic Page
5.1 PC to Micro-reader.....................................................................................30
5.1.1 Read RO, R/W .....................................................................................30
5.1.2 Program R/W Transponder..................................................................3 0
5.1.3 General Read Page of MPT.................................................................31
5.1.4 Program Page of MPT .........................................................................31
5.1.5 Lock Page of MPT................................................................................31
5.1.6 Selective Read Page of SAMPT ..........................................................32
5.1.7 Selective Program Page of SAMPT.....................................................32
5.1.8 Selective Lock Page of SAMPT ...........................................................33
5.2 Micro-reader to PC.....................................................................................33
5.2.1 Successful Read of RO........................................................................33
5.2.2 Successful Program Page 2 of MPT....................................................34
5.2.3 No Read....................................................... ....... .................................34
CHAPTER 5
29
Micro-reader - Reference Guide May ’00
5.1 PC to Micro-reader
5.1.1 Read RO, R/W
Byte Content Comment Description
(hex)
0 01 Start Mark 1 02 Length Two bytes follow excluding BCC 2 08 Command Perform Single command, send Power Burst I
Field (1) 3 32 Data Field (1) Power Burst I with 50 ms duration (charge-up) 4 38 BCC BCC over previous bytes excluding Start Mark
5.1.2 Program R/W Transponder
The following sequence of bytes programs a R/W transponder with:
00 00 00 00 00 00 00 01
MSByte LSByte
Byte Content Comment Description
(hex)
0 01 Start Mark 1 11 Length 17 bytes follow excluding BCC 2 E8 Command Perform Single command, no FBCC calculation,
Field (1) send Power Burst I & II with Data
Command Field (2) follows
3 06 Command Wireless synchronization, calculate DBCC of the
Field (2) R/W and MPT write data 4 32 Data Field (1) Power Burst I with 50 ms duration (charge-up) 5 0F Data Field (2) Power Burst II with 15 ms duration (Progr. burst) 6 0C Data Field (3) 12 Data Fields follow 7 BB Data Field (4) Write Keyword 8 EB Data Field (5) Write Password 9 01 Data Field (6) Programming data (LSByte)
10 00 Data Field (7) Programming data 11 00 Data Field (8) - : ­12 00 - : - - : ­13 00 - : - - : ­14 00 - : - - : ­15 00 - : - - : ­16 00 Data Field (13) Programming data (MSByte) 17 00 Data Field (14) Write Frame 18 03 Data Field (15) Write Frame 19 9C BCC BCC over previous bytes excluding Start Mark
30
May ’00 Chapter 5. Communication Protocol Examples
5.1.3 General Read Page of MPT
The following sequence of bytes reads page 2 of an MPT.
Byte Content Comment Description
(hex)
0 01 Start Mark 1 04 Length Four bytes follow excluding BCC 2 48 Command Perform Single command, send Power Burst I
Field (1) with data 3 32 Data Field (1) Power Burst I with 50 ms duration (charge-up) 4 01 Data Field (2) One Data Field follows 5 08 Data Field (3) Write Address specifying General Read Page 2 6 77 BCC BCC over previous bytes excluding Start Mark
5.1.4 Program Page of MPT
The following sequence of bytes programs page 2 of an MPT with:
00 00 00 00 00 2D C6 47
MSByte LSByte
Byte Content Comment Description
(hex)
0 01 Start Mark 1 0F Length 15 bytes follow excluding BCC 2 6C Command Perform Single command, calculate FBCC,
Field (1) send Power Burst I & II with Data 3 32 Data Field (1) Power Burst I with 50 ms duration (charge-up) 4 0F Data Field (2) Power Burst II with 15 ms duration (Progr. burst) 5 0B Data Field (3) 11 Data Fields follow 6 09 Data Field (4) Write Address specifying Program Page 2 7 47 Data Field (5) Programming data (LSByte) 8 C6 Data Field (6) Programming data 9 2D - : - - : -
10 00 - : - - : ­11 00 - : - - : ­12 00 - : - - : ­13 00 Data Field (11) Programming data 14 00 Data Field (12) Programming data (MSByte) 15 96 Data Field (13) DBCC (LSByte) 16 50 Data Field (14) DBCC (MSByte) 17 36 BCC BCC over previous bytes excluding Start Mark
5.1.5 Lock Page of MPT
The following sequence of bytes locks page 2 of an MPT.
Byte Content Comment Description
31
Micro-reader - Reference Guide May ’00
(hex)
0 01 Start Mark 1 05 Length Five bytes follow excluding BCC 2 6C Command Perform Single command, calculate FBCC,
Field (1) send Power Burst I & II with data 3 32 Data Field (1) Power Burst I with 50 ms duration (charge-up) 4 07 Data Field (2) Power Burst II with 15 ms duration (Progr. burst) 5 01 Data Field (3) One Data Field follows 6 0A Data Field (4) Write Address specifying Lock Page 2 7 5F BCC BCC over previous bytes excluding Start Mark
5.1.6 Selective Read Page of SAMPT
The following sequence of bytes reads page 2 of an SAMPT. The 24 bit selective address = 12 34 56
MSByte LSByte
Byte Content Comment Description
(hex)
0 01 Start Mark 1 07 Length 7 bytes follow excluding BCC 2 4C Command Perform Single command, calculate FBCC,
Field (1) send Power Burst I with Data 3 32 Data Field (1) Power Burst I with 50 ms duration (charge-up) 4 04 Data Field (2) 4 Data Fields follow 5 0B Data Field (3) Write Address specifying selective Read Page 2 6 56 Data Field (4) Selective Address LSB 7 34 Data Field (5) Selective Address 8 12 Data Field (6) Selective Address MSB 9 06 BCC BCC over previous bytes excluding Start Mark
5.1.7 Selective Program Page of SAMPT
The following sequence of bytes selective programs page 2 of an SAMPT with:
00 00 00 00 00 00 00 11
MSByte LSByte
The 24 bit selective address = 12 34 56
Byte Content Comment Description
(hex)
0 01 Start Mark 1 12 Length 18 bytes follow excluding BCC 2 6C Command Perform Single command, calculate FBCC,
Field (1) send Power Burst I & II with Data 3 32 Data Field (1) Power Burst I with 50 ms duration (charge-up) 4 0F Data Field (2) Power Burst II with 15 ms duration (Progr. burst) 5 0E Data Field (3) 14 Data Fields follow
MSByte LSByte
32
May ’00 Chapter 5. Communication Protocol Examples
6 09 Data Field (4) Write Address specifying Program Page 2 7 56 Data Field (5) Selective Address LSB 8 34 Data Field (6) Selective Address 9 12 Data Field (7) Selective Address MSB
10 11 Data Field (8) Programming data (LSByte) 11 00 Data Field (9) Programming data 12 00 - : - - : ­13 00 - : - - : ­14 00 - : - - : ­15 00 - : - - : ­16 00 - : - - : ­17 00 Data Field (15) Programming data (MSByte) 18 9F Data Field (16) DBCC (LSByte) 19 BD Data Field (17) DBCC (MSByte) 20 34 BCC BCC over previous bytes excluding Start Mark
5.1.8 Selective Lock Page of SAMPT
The following sequence of bytes locks page 2 of an SAMPT. The 24 bit selective address = 12 34 56
Byte Content Comment Description
(hex)
0 01 Start Mark 1 08 Length 8 bytes follow excluding BCC 2 6C Command Perform Single command, calculate FBCC,
3 32 Data Field (1) Power Burst I with 50 ms duration (charge-up) 4 0F Data Field (2) Power Burst II with 15 ms duration (Progr. burst) 5 04 Data Field (3) 4 Data Fields follow 6 0A Data Field (4) Write Address specifying selective Lock Page 2 7 56 Data Field (5) Selective Address LSB 8 34 Data Field (6) Selective Address 9 12 Data Field (7) Selective Address MSB
10 27 BCC BCC over previous bytes excluding Start Mark
5.2 Micro-reader to PC
5.2.1 Successful Read of RO
Byte Content Comment Description
(hex)
0 01 Start Mark 1 09 Length 9 bytes follow excluding BCC 2 0C Status Valid RO, Startbyte detected, DBCC O.K. 3 6A Data Field (1) Identification Data (LSByte)
MSByte LSByte
Field (1) send Power Burst I & II with Data
33
Micro-reader - Reference Guide May ’00
4 58 Data Field (2) Identification Data 5 4C - : - - : ­6 00 - : - - : ­7 00 - : - - : ­8 00 - : - - : ­9 00 Data Field (7) Identification Data
10 00 Data Field (8) Identification Data (MSByte) 11 7B BCC BCC over previous bytes excluding Start Mark
5.2.2 Successful Program Page 2 of MPT
Byte Content Comment Description
(hex)
0 01 Start Mark 1 0A Length 10 bytes follow excluding BCC 2 1E Status Valid MPT, Startbyte detected, DBCC O.K.,
FBCC O.K. 3 47 Data Field (1) New Identification Data (LSByte) 4 C6 Data Field (2) New Identification Data 5 2D - : - - : ­6 00 - : - - : ­7 00 - : - - : ­8 00 - : - - : ­9 00 Data Field (7) New Identification Data
10 00 Data Field (8) New Identification Data (MSByte) 11 09 Data Field (9) Read Address specifying successful progr. of
page 2
12 B1 BCC BCC over previous bytes excluding Start Mark
5.2.3 No Read
Byte Content Comment Description
(hex)
0 01 Start Mark 1 01 Length One byte follows excluding BCC 2 03 Status Other, no Startbyte, DBCC not O.K., FBCC not
O.K.
3 02 BCC BCC over previous bytes excluding Start Mark
34
Appendix A: CE Declaration
The Micro-reader module complies with the European CE requirements specified in the EMC Directive 89/336/EEC. The relevant documentation numbers are:
If the Micro-reader is operated from a mains power supply, all power connections and additional compo nents of the final de vice must comp ly with the Europ ean EMC di­rective.
Additional connections may have a length of up to 2 m maximum, or in fixed installa­tions up to 1 m maximum.
European customers must themselve s make sure t hat the final d evice conforms to the European EMC Directive.
APPENDIX A
CE Declaration
Declaration of Conformity11-06-02-005 Type Examination Certificate11-06-05-001
35
Appendix B: Demonstration Circuit
The Micro-reader module can be demonstrated using the circuit shown in Figure 17.
Figure 17: Micro-reader Demonstration Circuit
+ DC IN
+
10 µF 25V
- DC IN
NB: For design-in we recommend the SIPEX SP232 for the line driver chip to avoid potential interference problems
L78M05CV
0V
0.1 µF
+5V
RDEN
CRDM
10K
10K
WLSC
APPENDIX B
Demonstration Circuit
ANTENNA
12
11
MAX232
13 14
RS 232C
10 µF 25V
+
2
16
1
+
10 µF 25V
3 4
+
10 µF 25V
5
6
15
10 µF 25V
+
10K
2
26
27
24 22 19 16
MICROREADER
211525
+
10 µF 25V
0V
5
6
29
30
1
Ω
Ω
240Ω240
240
OKT
STAT
SYNC
3 2 5
36
Appendix C: Antenna Design
C.1 Introduction
This appendix gives an example of how you could construct an antenna to work with the micro-reader. It also provides information about calculating the Q factor and adapting the inductance range.
The antenna properties should be:
C.2 Antenna Construction
APPENDIX C
Antenna Design
Q factor less than 20 Inductance between 46 and 48 µH Recommended maximum size 200 mm x 200 mm
Item List:
Item Description Quantity
1 Enamelled solid copper wire, 0.2 mm 2.1 g 2 Tape, 10 mm wide 20 mm 3 Block cloth tape, 12 mm wide 0.12 m 4 Spiroband, 3 mm diameter 0.24 m 5 Screened antenna l ead 1 m
Method:
- Wind 15 turns of item 1 with a diameter of 75 mm.
- Leave about 50 mm free at the ends, cross the wires (at the +/- 50 mm point) and secure them together using the tape (item 2).
- twist the spriband (item 4) onto the c oil that you have just made, leaving the start and finish ends free.
- Strip the insulating br aid back at the end of th e antenna lea d (item 5). Wra p the start and finish ends at least three times around the bared ends and solder the joints (the polarity is not important).
- Tightly bind the soldered joints to the spriband using the cloth tape (item 3).
This method should result in a 47 µH antenna with a quality factor of approximately 17 - 18.
37
Micro-reader - Reference Guide May ’00
C.3 Q Factor
If the antenna’s Q factor exceeds 20:
1. The output capacitors will be overloaded and long term damage could result.
2. The antenna may still be resonating when the response from the transponder is received. Without built-in damping the data will not be correctly received.
3. The antenna may be detuned if there is any metal in the area.
The following formula provides an approximate method of calculating the Q factor of the antenna:
2πfL
Q
------------=
R
Where: f = 134200 Hz (Frequency = 134.2 kHz)
L = Inductance (henry) R = Series resistance (ohm)
Example:
The inductance (L) = 47µH. The resistance (R) = 2.2 Ohm.
π×
2
Q
-----------------------------------------------------------------=
134200×0.000047
×
2.2
=18
C.4 Adapting the Inductance Range
If your antenna is o utside of the r equi red indu ctanc e range o f 46 to 48 µH, y ou can adapt it to work w ith th e m icr o- reade r by a ddi ng an ex ter na l capacitor to it, eith er i n series or in parall el. You can use this exter nal capacitor to cha nge the inductance range by ± 5 µH.
You can work out the total resonance capacity using the following formula:
C
=
tot
If the antenna inductance is less than 46.1 µH you can add an extra capacitor (exter­nally) to the antenna be tween pi n 16 (A NT1) and pin 17 (AN TCAP ). The form ula to work out the value of this capacitor is:
C
ext
If the antenna inductance is more than 47.9 µH you can add an extra capacitor in se­ries with the antenn a b etwee n p in 19 (A NT2) a nd t he a nte nna. The formula to work out the value of this capacitor is:
39.636
----------------- -=
2.2
Ant
30ηF–=
2
f

π2L
⁄
14

C
tot
1
-----------
C
ext
1
---------- -
C
tot
38
–=
1
------------- -
ηF
30
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