NFC Digital Protocol - CWI

NFC-B TechnologyEnding ofPoll FrameAmplitude100 %Unmodulated carrierEoSFDTB,LISTENTR0PhaseTR0MINtnn.min (= tnn)TR1Beginning ofListen Frame= 0°= 180°No subcarrierUnmodulatedsubcarrier(a)TR0 >= TR0 MIN + t nnSoSEnding ofPoll FrameAmplitude100 %Unmodulated carrierEoSFDTB,LISTENTR0PhaseTR0MINtnn.min (=TR0-TR0MIN)TR1Beginning ofListen Frame= 0°= 180°No subcarrierUnmodulatedsubcarrier(b)TR0 < TR0 MIN + t nnFigure 18: t nn,min for NFC-BSoSRequirements 66: t nn,min - NFC-BListen Mode5.9.1.7 The NFC Forum Device MUST not produce any detectable disturbance during a timeperiod of at least t nn,min , defined as the minimum of TR0 – TR0 MIN and t nn , beforesending a Response. t nn,min MUST be measured before the start of TR1, as shown inFigure 18. For TR0 MIN , the Poll Mode value MUST be used. Refer to Appendix A.2 forthe value of t nn .The exact quantity of what constitutes ‘any detectable disturbance’ is not defined by this version ofthe specification.5.9.2 Frame Delay Time Listen→PollThe Frame Delay Time Listen→Poll (FDT B,POLL ) is the time between a Listen Frame and a PollFrame, as shown in Figure 13. The minimum value FDT B,POLL,MIN defines the time an NFCForum Device in Poll Mode has to wait before sending a new Poll Frame after receipt of a ListenFrame. A maximum value FDT B,POLL,MAX is not defined. FDT B,POLL,MIN is defined:FDT B,POLL,MIN = TR2 MINTR2 MIN is the minimum value of TR2, as shown in Figure 13. The value of TR2 MIN , supported bythe NFC Forum Device in Listen Mode, is indicated in the Protocol_Type of the SENSB_RESResponse as specified in Table 31 in Section 5.6.NFC Digital Protocol Page 66