Features • • • • • • • • • • • • Read/Write Anti-collision ID Transponder in Plastic Package Contactless Read/Write Data Transmission Inductive Coupled Power Supply at 125 kHz Basic Component: R/W IDIC e5551 Anti-collision Mode by Password Request – E.g. 10 Transponders Read Out in < 500 ms (RF/32, Maxblock 2) Depending on the Application Built-in Coil and Capacitor for Circuit Antenna Starts with Cyclical Data Read Out 224-bit EEPROM User Programmable in 32-bit Blocks Typically < 50 ms to Write and Verify a Block Write Protection by Lock Bits Malprogramming Protection Options Set by EEPROM – Bit Rate [bit/s]: RF/8, RF/16, RF/32, RF/40, RF/50, RF/64, RF/100, RF/128 – Modulation: BIN, FSK, PSK, Manchester, Bi-phase Application Standard Read/Write ID Transponder with Anticollision • • • • TK5551 Access Control Systems Process Control and Automation Systems Installation and Medical Equipment Asset Management Systems Description The TK5551 is a completely programmable R/W transponder which implements all important functions for identification systems, including anti-collision (e.g., 10 transponders in < 500 ms depending on the application). It allows the contactless reading and writing of data which are transmitted bi-directionally between a read/write base station and the transponder. It is a plastic-packaged device which accommodates the IDIC e5551 and also the antenna realized as an LC-circuit. No additional external power supply is necessary for the transponder because it receives power from the RF field generated by the base station. Data are transmitted by modulating the amplitude of the RF field. The TK5551 can be used to adjust and modify the ID code or any other stored data, e.g., rolling code systems. The on-chip 264-bit EEPROM (8 blocks, 33 bits per block) can be read and written block wise from the base station. The blocks can be protected against overwriting. One block is reserved for setting the operation modes of the IC. Another block can obtain a password to prevent unauthorized writing. Figure 1. System Block Diagram Base station U2270B read/ write IC MARC4 series microcontroller RF field TK5551 Transponder (e5551 + coil + C in plastic package) C e5551 Power Data Coil Rev. 4709B–RFID–10/03 General The transponder is the mobile part of the closed coupled identification system (see Figure 1 on page 1), whereas the read/write base station is based on the U2270B or on discrete solutions, and the read/write transponder is based on the IDIC e5551. The transponder is a plastic cube device consisting of the following parts: • The transponder antenna, realized as a tuned LC circuit • Read/write IDIC (e5551) with EEPROM Transponder Antenna The antenna consists of a coil and a capacitor for tuning the circuit to the nominal carrier frequency of 125 kHz. The coil has a ferrite core for improving the distance of read, write and programming operations. Read/Write IDIC e5551 The read/write IDIC e5551 is part of the transponder TK5551. The data are transmitted bi-directionally between the base station and the transponder. The transponder receives power via a single coil from the RF signal generated by the base station. The single coil is connected to the chip and also serves as the IC’s bi-directional communication interface. Data are transmitted by modulating the amplitude of the RF signal. Reading of register contents occurs by damping the coil by an internal load. Writing into registers occurs by interrupting the RF field in a specific way. The TK5551 transponder operates at a nominal frequency of 125 kHz. There are different bit rates and encoding schemes. The on-chip 264-bit EEPROM (8 block, 33 bits each) can be read and written block wise from the base station. The blocks can be protected against overwriting by using lock bits. One block is reserved for setting the operation modes of the IC. Another block contains a password to prevent unauthorized writing. See e5551 data sheet for more detailed information of the IDIC. Figure 2. Block Diagram of the e5551 POR Modulator Coil1 Analog front end Write decoder Mode register Memory (264 bit EEPROM) Bit rate generator Controller Coil2 Input register Test logic Vdd 2 Vss HV generator Test pads TK5551 4709B–RFID–10/03 TK5551 Absolute Maximum Ratings Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability Parameters Symbol Value Unit Operating temperature range Tamb -40 to +85 °C Storage temperature range Tstg -40 to +125 °C Assembly temperature t < 5 minutes Tass 170 °C Magnetic field strength at 125 kHz Hpp 1000 A/m Operating Characteristics: Transponder Tamb = 25°C, f = 125 kHz, unless otherwise specified Parameters Test Conditions Inductance Symbol Min. L Typ. Max. 3.8 Unit mH LC Circuit, Hpp = 20 A/m Resonance frequency Room temperature fr 120 125 130 kHz QLC 13 No influence to other tags in the field Hpp not 4 A/m Tamb = -40°C Hpp -40 30 A/m Tamb = 25°C Hpp 25 18 A/m Tamb = 85°C Hpp 85 17 A/m Programming mode Tamb = 25°C Hpp 50 A/m Data retention EEPROM Tamb = 25°C tretention Quality factor Magnetic Field Strength (H) Maximum field strength where tag does not modulate Field strength for operation Programming cycles EEPROM Programming time/block 10 Years 100,000 RF = 125 kHz Maximum field strength tp 16 ms 600 Hpp max A/m Modulation Range (see also H-DV Curve) Modulation range Hpp = 20 A/m Hpp = 30 A/m Hpp = 50 A/m Hpp = 100 A/m DV 4.0 6.0 8.0 8.0 V 3 4709B–RFID–10/03 Figure 3. Typical TK Range of Resonance Frequency 4 TK of fres (%) 3 2 1 0 -1 -2 -3 -4 -40 -20 0 20 40 60 80 100 Temperature (°C) Figure 4. Typical H-DV Curve 9 8 7 DV (V) 6 5 4 3 2 1 0 0 20 40 60 80 100 120 HPP (A/m) Figure 5. Measurement of the Modulation Range DV Output voltage of the testing application V1 Vmod DV = V1 - Vmod 4 TK5551 4709B–RFID–10/03 TK5551 Measurement Assembly All parameters are measured in a Helmholtz arrangement, which generates a homogenous magnetic field (see Figure 6 and Figure 7). A function generator drives the field generating coils, so the magnetic field can be varied in frequency and field strength. Figure 6. Testing Application SENSING COILS ( IN PHASE ) OUTPUT VOLTAGE SUBTRACTOR TK5551 AMPLIFIER 1:10 REFERENCE COIL ( IN PHASE ) REFERENCE COIL ( IN PHASE ) FIELD GENERATING COILS ( IN PHASE ) FUNCTION GENERATOR Figure 7. Testing Geometry 30 mm 15 mm TK5551 24 mm 60 mm REFERENCE COIL REFERENCE COIL 2 mm SENSING COIL SENSING COIL 5 mm FIELD GENERATING COIL FIELD GENERATING COIL 5 4709B–RFID–10/03 Writing Data into the TK5551 The write sequence of the TK5551 is shown below. Writing data into the transponder occurs by interrupting the RF field with short gaps. After the start gap the standard write OP code (10) is followed by the lock bit. The next 32 bits contain the actual data. The last 3 bits denote the destination block address. If the correct number of bits have been received, the actual data is programmed into the specified memory block. Figure 8. Write Protocol RF field Standard OP-code 1 0 Start gap Address bits (e.g. block 4) 0 1 0 > 64 clocks 0 Lock bit Write mode Read mode Write Data Decoding 32 bit The time elapsing between two detected gaps is used to encode the information. As soon as a gap is detected, a counter starts counting the number of field clock cycles until the next gap is detected. Depending on how many field clocks elapse, the data is regarded as '0' or '1'. The required number of field clocks is shown in Figure 9. A valid '0' is assumed if the number of counted clock periods is between 16 and 32, for a valid '1' it is 48 or 64 respectively. Any other value being detected results in an error, and the device exits write mode and returns to read mode. Figure 9. Write Data Decoding Scheme Field clock cycles Write data decoder Actual Behavior of the Device 1 16 fail 32 0 48 fail 64 1 writing done The TK5551 detects a gap if the voltage across the coils decreases below the threshold value of an internal MOS transistor. Until then, the clock pulses are counted. The number given for a valid '0' or '1' (see Figure 9) refers to the actual clock pulses counted by the device. However, there are always more clock pulses being counted than were applied by the base station. The reason for this is the fact that an RF field cannot be switched off immediately. The coil voltage decreases exponentially. So although the RF field coming from the base station is switched off, it takes some time until the voltage across the coils reaches the threshold value of an internal MOS transistor and the device detects the gap. Referring to the following diagram (see Figure 10 on page 7), this means that the device uses the times t0 internal and t1 internal. The exact times for t0 and t1 are dependent on the application (e.g., field strength, etc.) Measured write-time frames of the IDIC demo kit software are: t0 = 50 ms to 130 ms t1 = 270 ms to 390 ms tgap = 180 ms to 400 ms Antennas with a high Q-factor require longer times for tgap and shorter time values for t0 and t1. 6 TK5551 4709B–RFID–10/03 TK5551 Figure 10. Ideal and Real Behavior Signals t1 tgap t0 t1 Coil voltage 1 0 1 tgap t0 Coil voltage 1 t1 internal Gap detect 0 1 t0 internal Gap detect Ideal behavior Actual behavior RF level reduces to zero immediately RF level decreases exponentially Operating Distance The maximum distance between the base station and the TK5551 depends mainly on the base station, the coil geometries and the modulation options chosen (see “U2270B Antenna Design Hints” and the “U2270B” data sheet). Under laboratory conditions, a distance of up to 9 cm can be reached. For optimized distance, please refer to the application note. When using Atmel’s U2270B demo board, the typical distances in the range of 0 cm to 5 cm can be achieved. Anti-collision Mode by Password Request (AOR = Answer-OnRequest) The AOR mode is an anti-collision procedure for transponders to read, e.g., 10 transponders in the field during 500 ms (RF/32, maxblock 2). The number of transponders and the time to read out are dependent on the application. If the AOR mode has been configured by AOR bit at block 0, the transponder remains in sleep mode while putting it into the field. If the specified AOR wake-up command is sent, the dedicated transponder generates an internal RESET (see section “OP Code Formats” in the e5551 data sheet). Due to the RESET the transponder is woken up. That means, the transponder is able to modulate the field (read mode). The AOR wake-up command consists of the OP code and the 32-bit password. The time duration to send the AOR wake-up sequence is between 8.7 ms and 27.5 ms according to Figure 10. The time duration is dependent on the minimum/maximum values of the measured write-time frames and the content of the password. To select another transponder in the field, it is necessary to send the stop OP code to stop the modulation of the transponder. 7 4709B–RFID–10/03 Application Figure 11. Complete Transponder System with the Read/Write Base Station IC U2270B 5V 110 kΩ 5V VEXT VS VBatt U2270B DVS 22 µF 47 nF VDD M44C260 RF MS CFE OE Standby Output Gain 680 pF Input 4.7 kΩ 1N4148 BP00 BP01 BP02 BP03 BP10 osc IN 32 kHz osc OUT COIL2 470 kΩ 1.5 nF 1.2 nF 1.35 mH R Read/write circuit 100 nF Microcontroller COIL1 Data Power C31 e5551 DGND GND V SS fres = 1/ (2π√LC) = 125 kHz Transponder TK5551 8 TK5551 4709B–RFID–10/03 TK5551 Ordering Information Extended Type Number Package Remarks TK5551M-PP Plastic package All kinds of modulation; RF/8, RF/16, RF/32, RF/40, RF/50,RF/64,RF/100 and RF/128(1) Default programmed: Manchester Modulation, RF/32, MAXBLK = 2 Note: 1. See data sheet e5551 Package Information Dimensions in mm 9 4709B–RFID–10/03 Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Regional Headquarters Europe Atmel Sarl Route des Arsenaux 41 Case Postale 80 CH-1705 Fribourg Switzerland Tel: (41) 26-426-5555 Fax: (41) 26-426-5500 Asia Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon Hong Kong Tel: (852) 2721-9778 Fax: (852) 2722-1369 Japan 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581 Atmel Operations Memory 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 RF/Automotive Theresienstrasse 2 Postfach 3535 74025 Heilbronn, Germany Tel: (49) 71-31-67-0 Fax: (49) 71-31-67-2340 Microcontrollers 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 La Chantrerie BP 70602 44306 Nantes Cedex 3, France Tel: (33) 2-40-18-18-18 Fax: (33) 2-40-18-19-60 ASIC/ASSP/Smart Cards 1150 East Cheyenne Mtn. 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