SL3S1203_1213 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet
COMPANY PUBLIC
Rev. 4.4 — 17 March 2014
178844 21 of 37
NXP Semiconductors
SL3S1203_1213
UCODE G2iL and G2iL+
10.7.5 ChangeEAS
3
UCODE G2iL equipped RFID tags will also feature a stand-alone operating EAS alarm
mechanism for fast and offline electronic article surveillance. The PSF bit of the
Configuration Word directly relates to the EAS Alarm feature. With an PSF bit set to '1' the
tag will reply to an EAS_Alarm command by backscattering a 64 bit alarm code without
the need of a Select or Query. The EAS is a built-in solution so no connection to a
backend database is required. In case the EAS_Alarm command is not implemented in
the reader a standard EPC SELCET to the Configuration Word and Query can be used.
When using standard SELECT/QUERY the EPC will be returned during inventory.
ChangeEAS can be executed from the Secured state only. The command will be ignored
if the Access Password is zero, the command will also be ignored with an invalid CRC-16
or an invalid handle, the G2iL will than remain in the current state. The CRC-16 is
calculated from the first command-code bit to the last handle bit. A frame-sync must be
pre-pended the command.
The G2iL reply to a successful ChangeEAS will use the extended preamble, as
appropriate (i.e. a Tag shall reply as if TRext=1) regardless of the TRext value in the
Query that initiated the round.
After sending a ChangeEAS an interrogator shall transmit CW for less than T
Reply
or
20 ms, where T
Reply
is the time between the interrogator's ChangeEAS command and the
G2iL backscattered reply. An interrogator may observe three possible responses after
sending a ChangeEAS, depending on the success or failure of the operation
• ChangeEAS succeeds: After completing the ChangeEAS a G2iL will backscatter the
reply shown in Table 21
comprising a header (a 0-bit), the handle, and a CRC-16
calculated over the 0-bit and handle. If the interrogator observes this reply within
20 ms then the ChangeEAS completed successfully.
• The G2iL encounters an error: The G2iL will backscatter an error code during the CW
period rather than the reply shown in Table 21
(see EPCglobal Spec for error-code
definitions and for the reply format).
Table 19. Reset ReadProtect command-response table
Starting State Condition Response Next State
ready all – ready
arbitrate, reply,
acknowledged
all – arbitrate
open valid handle & valid access password Backscatter handle,
when done
open
valid handle & invalid access password – arbitrate
invalid handle – open
secured valid handle & valid access password Backscatter handle,
when done
secured
valid handle & invalid access password – arbitrate
invalid handle – secured
killed all – killed
