139037 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet
COMPANY PUBLIC
Rev. 3.8 — 11 November 2013
139038 19 of 48
NXP Semiconductors
SL3ICS1002/1202
UCODE G2XM and G2XL
13.5 Data integrity
The G2X ignores invalid commands. In general, "invalid" means a command that (1) is
incorrect given the current the G2X state, (2) is unsupported by the G2X, (3) has incorrect
parameters, (4) has a CRC error, (5) specifies an incorrect session, or (6) is in any other
way not recognized or not executable by the G2X. The actual definition of "invalid" is
state-specific and defined, for each G2X state, in n Section 17
, Ref. 1 Annex B and
Annex C.
All UCODE G2X backscatter error codes are summarized in Section 17
, Ref. 1 Error
codes, Annex I. For a detailed description of the individual backscatter error situations
which are command specific please refer to the Section 17
, Ref. 1 individual command
description section 6.3.2.10.
13.6 CRC
A CRC-16 is a cyclic-redundancy check that an interrogator uses when protecting certain
R=>T commands, and the G2X uses when protecting certain backscattered T=>R
sequences. To generate a CRC-16 an interrogator or the G2X first generates the CRC-16
precursor shown in Section 17
, Ref. 1 Table 6.11, then take the ones-complement of the
generated precursor to form the CRC-16. For a detailed description of the CRC-16
generation and handling rules refer to Section 17
, Ref. 1, chapter 6.3.2.1.
The CRC-5 is only used to protect the Query command (out of the mandatory command
set). It is calculated out of X5 + X3 + 1. For a more detailed CRC-5 description refer to
Section 17
, Ref. 1, table 6.12.
For exemplary schematic diagrams for CRC-5 and CRC-16 encoder/decoder refer to
Section 17
, Ref. 1, Annex F.
For a CRC calculation example refer to Section 15.1
, Table 27 and Table 28.
