ib technology

8

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:

0xFF

Empty list

Byte 21:

0xFF

Byte 22:

0xFF

Byte 23:

0xFF

Byte 24:

(MSB) Tag identity code

Byte 25:

Byte 26:

Byte 27:

(LSB)

Byte 28:

(MSB) Tag identity code

Byte 29:

Byte 30:

Byte 31:

(LSB)

-

-

Byte 255:

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.

B7

B0

Command:

0 1 0 0 0 1 1 0

(Ascii “F”, 0x46)

Argument1:

0 1 0 1 0 1 0 1

0x55

Argument1:

1 0 1 0 1 0 1 0

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).