NFC Digital Protocol - CWI

NFC-A Technology4.7.2 SDD_RES ResponseIn response to a SDD_REQ Command with a SEL_PAR value equal to 20h, all NFC ForumDevices in Listen Mode in the Operating Field transmit the requested cascade level of theirNFCID1 (NFCID1 CLn, with n=1, 2 or 3). The NFCID1 of an NFC Forum Device in ListenMode consists of 4, 7, or 10 bytes. The length of the Response containing a complete NFCID1cascade level (i.e., NFCID1 CL1, or NFCID1 CL2, or NFCID1 CL3) is always 5 bytes. Thecoding of the Response depends on the value of the SEL_CMD byte and the size of the NFCID1.Table 13 specifies how to code the SDD_RES Response containing a complete NFCID1 cascadelevel.Table 13: SDD_RES Response (NFCID1 CLn + BCC)SEL_CMD NFCID1 Size SDD_RES Response93h 4 CL1: nfcid1 0 nfcid1 1 nfcid1 2 nfcid1 3 BCC93h > 4 CL1: CT nfcid1 0 nfcid1 1 nfcid1 2 BCC95h 7 CL2: nfcid1 3 nfcid1 4 nfcid1 5 nfcid1 6 BCC95h > 7 CL2: CT nfcid1 3 nfcid1 4 nfcid1 5 BCC97h 10 CL3: nfcid1 6 nfcid1 7 nfcid1 8 nfcid1 9 BCC• nfcid1 n is the n th byte of the complete NFCID1, with nfcid1 0 being the most significantbyte.• CT is the cascade tag.• BCC is an exclusive-OR over the first 4 bytes of the SDD_RES Response.Table 14 specifies the content of nfcid1 0 in the case of a single size NFCID1.Table 14: nfcid1 0 for Single-size NFCID1nfcid1 008hx0h to x7hx9h to xEh18h, 28h, 38h, 48h, 58h, 68h,78h, 88h, 98h, A8h, B8h,C8h, D8h, E8h, F8hxFhDescriptionnfcid1 1 to nfcid1 3 are dynamically generatedFixed diversified number (the assignment is out of scope of thisspecification)RFUNFC Digital Protocol Page 31