Datasheet

PN532_C1 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2017. All rights reserved.
Product data sheet
COMPANY PUBLIC
Rev. 3.6 — 28 November 2017
115436 173 of 222
NXP Semiconductors
PN532/C1
Near Field Communication (NFC) controller
8.6.23.34 CIU_ModWidth register (6314h)
Controls the setting of the modulation width.
Table 240. CIU_ModWidth register (address 6314h) bit allocation
Bit 7 6 5 4 3 2 1 0
Symbol ModWidth[7:0]
Reset 00100110
Access R/W R/W R/W R/W R/W R/W R/W R/W
Table 241. Description of CIU_ModWidth bits
Bit Symbol Description
7 to 0 ModWidth[7:0] These bits define the width of the Miller modulation as initiator in Active
and Passive Communication mode as multiples of the carrier frequency
(ModWidth+1 / fc). The maximum value is half the bit period.
Acting as a target in Passive Communication mode at 106 kbit/s or in
Card Operating mode for ISO/IEC 14443A/MIFARE these bits are used
to change the duty cycle of the subcarrier frequency.
Number of cycles with low value: NCLV = (Modwidth modulo 8)+1
Number of cycles with high value: NCHV = 16 - NCLV