Product data

MFRC631 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2014. All rights reserved.
Product data sheet
COMPANY PUBLIC
Rev. 3.3 — 4 February 2014
227433 84 of 120
NXP Semiconductors
MFRC631
High performance ISO/IEC 14443 A/B reader solution
9.10 Transmitter configuration registers
9.10.1 TxDataNum
3 to 2 RxCRCtype Defines which type of CRC (CRC8/CRC16/CRC5) is calculated:
• 00h -- CRC5
• 01h -- CRC8
• 02h -- CRC16
• 03h -- RFU
1 RxCrcInvert If set, the CRC check is done for the inverted CRC.
0 RxCrcEn If set, the CRC is checked and in case of a wrong CRC an error flag is
set. Otherwise the CRC is calculated but the error flag is not modified.
Table 134. Receiver CRC preset value configuration
RXPresetVal[6...4] CRC16 CRC8 CRC5
0h 0000h 00h 00h
1h 6363h 12h 12h
2h A671h BFh -
3h FFFEh FDh -
4h---
5h---
6h User defined User defined User defined
7h FFFFh FFh 1Fh
Table 133. RxCrcCon bits
Bit Symbol Description
Table 135. TxDataNum register (address 2Eh)
Bit 7 6 5 4 3 2 1 0
Symbol RFU RFU- RFU- KeepBitGrid DataEn TxLastBits
Access
rights
r/w r/w r/w
Table 136. TxDataNum bits
Bit Symbol Description
7to5 RFU -
4 KeepBitGrid If set, the time between consecutive transmissions starts is a multiple
of one ETU. If cleared, consecutive transmissions can even start
within one ETU
3 DataEn If cleared - it is possible to send a single symbol pattern.
If set - data is sent.
2 to 0 TxLastBits Defines how many bits of the last data byte to be sent. If set to 000b all
bits of the last data byte are sent.
Note - bits are skipped at the end of the byte.
Example - Data byte B2h (sent LSB first).
TxLastBits = 011b (3h) => 010b (LSB first) is sent
TxLastBits = 110b (6h) => 010011b (LSB first) is sent