The MicroRWD Hitag2 version is a complete reader and tag acceptance solution for Hitag 2 ® RF transponders. The solution only needs a 700uH antenna coil connected and 5 V DC supply to be a fully featured read/write system. 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 RWD 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 Hitag 2 ® transponders provide 256 bits (32 bytes) of read/write EEPROM memory arranged as 8 partitioned 32 bit pages. An area of 128 bits (16 bytes) is open for general user data. The Hitag 2® transponders are configurable for different modes of operation and the MircoRWD Hitag2 version supports the high security PASSWORD mode only. This feature uses two password codes stored both in the H2 transponder and the RWD that are mutually exchanged when a tag is brought into the RF field; the tag is only unlocked for read/write operations if these codes exactly agree.
The MicroRWD Hitag2 is essentially a proximity system and a Read/Write range of up to 20 cm can be achieved with the same level of reliable communication and EMC resilience. The unique AST (Adaptive Sampling) feature allows the RWD to continually adjust and retune the sampling to 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 4k bits/second of data transfer and the total time to read a 32-bit page takes less than 50ms.