RWD_QT Datasheet, PDF (8/19 Pages) rfsolutions.ltd – The MicroRWD “QT” (Quad-Tag) version is a complete 125kHz reader solution for Hitag 1,

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Start of authorised tag identity codes. List is terminated with FF FF FF FF sequence.
List is regarded as empty (all identity codes valid) if first code sequence in list is (FF FF FF FF).
NOTE that identity codes are four bytes long.
Identity codes are taken as Page 0 serial numbers for H1 / H2 types and transponder memory bytes 1 to 4 for
EM400X and MCRF200 types, ignoring most significant first byte (byte 0).
List can hold up to 60 (4 byte) identity codes.
Byte 20:
Byte 21:
Byte 22:
Byte 23:
Byte 24:
Byte 25:
Byte 26:
Byte 27:
Byte 28:
Byte 29:
Byte 30:
Byte 31:
-
-
Byte 255:
0xFF
0xFF
0xFF
0xFF
Empty list
(MSB) Tag identity code
(LSB)
(MSB) Tag identity code
(LSB)
Last Internal EEPROM location
Factory Reset
Command to restore Factory default EEPROM values and perform hardware Reset operation.
The 0x55 0xAA parameters protect against accidental operation.
After Reset, the Green LED flashes five times indicating the successful loading of the Factory
default values.
Command:
Argument1:
Argument1:
B7
B0
01000110
01010101
10101010
(Ascii “F”, 0x46)
0x55
0xAA
Reset occurs after the command is processed so there is no Acknowledge byte reply.
Operation of Identity code authorisation list
The Micro RWD QT reader only allows full communication with any of the transponders if
an initial level of security has been passed. The system works by firstly reading the tag
identity code (serial number), which is the four bytes from page 0 (first page) of H1/S or H2
types and bytes 1 to 4 of the EM400X or MC200 memory arrays ignoring the most significant
first byte (byte 0). The Micro RWD internal EEPROM is then checked to see if this serial
number is stored in the authorisation list located from byte 20 onwards. If the tag serial
number is matched to a stored serial number or the list is empty then the tag has passed the
validation test. If the Micro RWD has FF FF FF FF (hex) stored at EEPROM locations 20 to
23 then the list is treated as empty and all tags are accepted.
Full communication is only allowed if this initial security check has been passed (or the
Micro RWD authorisation list is empty).
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