NFC Digital Protocol - CWI

ISO-DEP ProtocolRequirements 168: CRCPoll and Listen Mode13.1.4.1 A block MUST contain an EoD at the position, as indicated in Figure 30.For Type 4A Tag platform, the EoD MUST contain a CRC_A as defined in Section 4.4.For Type 4B Tag platform, the EoD MUST contain a CRC_B as defined in Section 5.4.13.2 Protocol Operation13.2.1 General RulesGeneral rules for the Type 4A Tag and Type 4B Tag transmission protocol are described inSection 7.13.2.2 Frame Waiting Time ExtensionWhen the Card Emulator needs more time than the defined FWT to process the received block, ituses an S(WTX) request for a waiting time extension. An S(WTX) request contains a 1-byte INFfield as specified in Table 84.Table 84: Format of INF Field of an S(WTX) Requestb8 b7 b6 b5 b4 b3 b2 b1 Meaningx x Power level indicationx x x x x x WTXM• Power Level IndicatorThe two most significant bits—b8 and b7—code the power level indication.Requirements 169: Power Level IndicationPoll ModeThe Reader/Writer MAY support a power levelindication different from 00b.Listen Mode13.2.2.1 The power level indication is notused and the bits MUST be set to00b.• WTXMThe bits b6 to b1 code WTXM. The WTXM is coded in the range from 1 to 59.The Reader/Writer acknowledges the request by sending an S(WTX) Response containingalso a 1-byte INF field. The INF field consists of two parts that contain the same WTXM asreceived in the request (see Table 85).NFC Digital Protocol Page 132