mfrc531 NXP Semiconductors, mfrc531 Datasheet - Page 82

• Manufacturer Part Number: mfrc531
• Description: Iso/iec 14443 Reader Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
MFRC531_34
Product data sheet
PUBLIC
11.2.3 Transceive command 1Eh
11.2.4 States of the card communication
Table 137. Transceive command 1Eh
The Transceive command first executes the Transmit command (see
page
transmitted is sent using the FIFO buffer and all data received is written to the FIFO buffer.
The Transceive command can only be started by the microprocessor.
Remark: To adjust the timing relationship between transmitting and receiving, use the
RxWait register. This register is used to define the time delay between the last bit
transmitted and activation of the receiver. In addition, the BitPhase register determines the
phase-shift between the transmitter and receiver clock.
The status of the transmitter and receiver state machine can be read from bits
ModemState[2:0] in the PrimaryStatus register.
The assignment of ModemState[2:0] to the internal action is shown in
Table 138. Meaning of ModemState
Command Value
Transceive
ModemState
[2:0]
000
001
010
011
100
101
110
76) and then starts the Receive command (see
1Eh
State
Idle
TxSOF
TxData
TxEOF
GoToRx1
GoToRx2
PrepareRx
AwaitingRx
Rev. 3.4 — 26 January 2010
Action
transmits data from FIFO buffer to the card
and then automatically activates the
receiver
intermediate state passed, when receiver finishes
waiting until the RxWait register time period expires
Description
transmitter and/or receiver are not operating
transmitting the SOF pattern
transmitting data from the FIFO buffer (or redundancy CRC check
bits)
transmitting the EOF pattern
intermediate state passed, when receiver starts
receiver activated; waiting for an input signal on pin RX
056634
Section 11.2.2 on page
Arguments
and data
data stream
ISO/IEC 14443 reader IC
MFRC531
Section 11.2.1 on
Table
© NXP B.V. 2010. All rights reserved.
138.
Returned
data
data stream
79). All data
82 of 116