Data Sheet

Product data sheet

COMPANY PUBLIC

Rev. 3.9 — 27 April 2016

112139 46 of 95

NXP Semiconductors

MFRC522

Standard performance MIFARE and NTAG frontend

9.3.1.14 BitFramingReg register

Adjustments for bit-oriented frames.

9.3.1.15 CollReg register

Defines the first bit-collision detected on the RF interface.

Table 47. BitFramingReg register (address 0Dh); reset value: 00h bit allocation

Bit 7 6 5 4 3 2 1 0

Symbol StartSend RxAlign[2:0] reserved TxLastBits[2:0]

Access W R/W - R/W

Table 48. BitFramingReg register bit descriptions

Bit Symbol Value Description

7 StartSend 1 starts the transmission of data

only valid in combination with the Transceive command

6 to 4 RxAlign[2:0] used for reception of bit-oriented frames: defines the bit

position for the first bit received to be stored in the FIFO buffer

example:

0 LSB of the received bit is stored at bit position 0, the second

received bit is stored at bit position 1

1 LSB of the received bit is stored at bit position 1, the second

received bit is stored at bit position 2

7 LSB of the received bit is stored at bit position 7, the second

received bit is stored in the next byte that follows at bit

position 0

These bits are only to be used for bitwise anticollision at

106 kBd, for all other modes they are set to 0

3 reserved - reserved for future use

2 to 0 TxLastBits[2:0] - used for transmission of bit oriented frames: defines the

number of bits of the last byte that will be transmitted

000b indicates that all bits of the last byte will be transmitted

Table 49. CollReg register (address 0Eh); reset value: xxh bit allocation

Bit 7 6 5 4 3 2 1 0

Symbol ValuesAfterColl reserved CollPosNotValid CollPos[4:0]

Access R/W - R R

Table 50. CollReg register bit descriptions

Bit Symbol Value Description

7 ValuesAfterColl 0 all received bits will be cleared after a collision

only used during bitwise anticollision at 106 kBd,

otherwise it is set to logic 1

6 reserved - reserved for future use

5 CollPosNotValid 1 no collision detected or the position of the collision is

out of the range of CollPos[4:0]