NFC Digital Protocol - CWI

NFC-A Technology4.2.2 Listen→Poll Coding SchemeThe patterns E and D are used to code the digital alphabet Logic “0” and Logic “1”. Logic “0”sand Logic “1”s, referred to as data bits in the following, are the components of frames.Requirements 9: Bit Level Coding Listen→Poll – NFC-APoll Mode4.2.2.1 The NFC Forum Device MUSTdecode Logic “0” and Logic “1” asfollows:• If the NFC Forum Device detectspattern D, then it MUST decodethis as Logic “1”.• If the NFC Forum Device detectspattern E, then it MUST decodethis as Logic “0”.Invalid patterns MAY be treated as TransmissionErrors, or the device MAY use implementationdependentmethods to decode an invalid patterninto a Logic “0” or Logic “1”.Listen Mode4.2.2.2 The NFC Forum Device MUSTcode Logic “0” and Logic “1” asfollows:• Logic “1”: pattern D• Logic “0”: pattern E4.3 Frame FormatData bits, when transmitted between NFC Forum Devices, are grouped within frames. The formatof a frame is different for each Technology. NFC-A Technology groups the data bits together in aframe by adding an SoF and an EoF. A parity bit (P) is added at the end of each 8 data bits.This section defines the frames of NFC Forum Devices configured for NFC-A Technology. NFC-A Technology uses three types of frames: short frame, standard frame, and bit-oriented SDDframe. The short frame is used to initiate communication (wake-up). The standard frame is usedfor data exchange. The bit-oriented SDD frame is used for collision resolution.NOTEDefinitions in Section 4.3 overrule deviating definitions in [ISO/IEC_18092].NFC Digital Protocol Page 21