SL3ICS1002 datasheet(27/56 Pages) NXP

27 / 56 page

139036

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Product data sheet

COMPANY PUBLIC

Rev. 3.6 — 10 March 2011

139036

27 of 56

NXP Semiconductors

SL3ICS1002/1202

UCODE G2XM and G2XL

14.5 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 18, Ref. 1 Annex B and

Annex C.

All UCODE G2X backscatter error codes are summarized in Section 18, 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 18, Ref. 1 individual command

description section 6.3.2.10.

14.6 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 18, 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 18, 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 18, Ref. 1, table 6.12.

For exemplary schematic diagrams for CRC-5 and CRC-16 encoder/decoder refer to

Section 18, Ref. 1, Annex F.

For a CRC calculation example refer to Section 16.1, Table 32 and Table 33.

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