The MicroRWD QT LP SMT (Quad-Tag) low-power version is a complete 125kHz reader solution for HITAG® 1, HITAG® S256/S2048 (Plain Memory mode), HITAG® 2 (Password mode), EM400X/4102 and MCRF200I/123 passive RFID transponder types. The module is packaged as a 16-pin low-profile SMT device and only needs a 500-800 μH antenna coil connected and 5 V DC supply to be a fully featured read/write system. The MicroRWD QT LP SMT version behaves in the same manner as the standard reader except that it has a lower average current consumption. Current consumption depends upon polling
rate and antenna circuit impedance at 125KHz. As with other RWD modules, all commands and data response are via a simple TTL level RS232 interface. The module provides internal EEPROM memory for holding lists of authorised identity codes, a manual override switch facility and has LED drives to give visual indication of acceptance.
The MicroRWD also has a TTL level RS232 interface that allows a host system to communicate with the RWD if necessary, so that system features can be customised, configurations changed and tag read/write data handled by the host system. The MicroRWD QT SMT version uses the same basic hardware as previous MicroRWD versions but has a larger memory microcontroller to accommodate the software for reading four different tag types. The QT SMT is host interface and command protocol compatible with the individual H1/S, H2, EM400X and MCRF200 reader versions. Functionally, the only difference is that the MicroRWD QT internal EEPROM parameter map has been changed to accommodate all The RWD-QT-LP-SMT is a new surface mount (SMT) package option of the RWD-QT-LP module. Like the dual in line (DIL) module, it supports HITAG® S256, HITAG® S2048, HITAG® 1, HITAG® 2 and EM4XXX transponders at 125 kHz. It is designed for modern printed circuit board surface mount assembly and minimal size requirements. Evaluation and development is covered by a baseboard product (RWD-QT-SMT-Baseboard – Eccel Stock Code 000325). This baseboard offers a USB connection interface capability to the module and expansion of the pins for circuit development purposes.
As with the individual MicroRWD versions, the RWD QT LP SMT is essentially a proximity system and a Read/Write range of up to 20cm can beachieved with the same level of reliable communication and EMC resilience. The unique AST (Adaptive Sampling) feature allows the RWD to continually adjust and re-tune the samplingto allow for inductive changes in the RF field, an essential feature for real-world reliability and robust operation.The communication protocol with the tags can achieve up to 4k bits/second of data transferand the total time, for example, to read a HITAG® 2 four-byte page, including reading of the serial number, selecting the tag and the read operation itself takes less than 100ms. The MicroRWD QT LP SMT is ideally suited to battery powered applications; when power (5 V DC) is first applied to the module the red and green LED outputs “flash” once to indicate successful power-up. The device can also check for broken or shorted antenna and can even detect very badly tuned antennas, these problems are indicated by the red LED output “flashing” continuously until the fault has been rectified.