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 136 of 222
NXP Semiconductors
PN532/C1
Near Field Communication (NFC) controller
8.6.20.10 Receive command
The CIU activates the receiver path and waits for any data stream to be received. The
correct settings for the expected mode have to be set before starting this command.
This command terminates automatically when the reception ends and the active
command is Idle.
In case of data rates at 212 kbps or 424 kbps with NFC or FeliCa framing, the reception
ends when the number of bytes indicated by the LEN byte (received) are received. If less
bytes than indicated by LEN are received from the RF, the CIU will sample noise to add
the missing bytes. If more bytes than indicated by LEN are received from the RF, the last
bytes will be ignored. When LEN is 0, the frame is ignored, and the PN532 waits for a new
frame.
In case of data rate at 106 kbps in NFC communication mode, the reception ends when
the CIU detects an end of frame, except if the CIU detects more bytes than indicated by
the received LEN byte. In that case, after receiving LEN bytes, a new reception restarts
and the CIU timer starts (if Tauto in register CIU_TMode Table 252
is set to logic 1). The
end of reception is then seen if a new valid frame is received or the firmware has to end
the reception phase on time-out.
In all other cases, the end of the reception is detected by the end of frame.
In case no frame is received and Tauto in register CIU_TMode Table 252
is set to logic 1,
then TimerIRQ in register CommIRQ is set to logic 1. The firmware has to end the
reception phase.
Note: If the bit RxMultiple in the register CIU_RxMode is set to logic 1, the Receive
command does not terminate automatically. It has to be terminated by setting any other
command in the CIU_Command register.
8.6.20.11 Transceive command
This circular command repeats transmitting data from the FIFO and receiving data from
the RF field continuously. If the bit Initiator in the register CIU_Control is set to logic 1, it
indicates that the first action is transmitting and after having finished transmission the
receiver is activated to receive data. If the bit Initiator in the CIU_Control register is set to
logic 0, the first action is receiving and after having received a data stream, the transmitter
is activated to transmit data. In the second configuration the PN532 first acts as a receiver
and if a data stream is received it switches to the Transmit mode.
The end of the reception phase is detected in the same way than for the receive command
and also when the RF field is cut.
The transceive command always take into account the presence or absence of the RF
field. No transmission or reception can be done when no RF field.
Table 168. Transceive command scenario
Communication step Initiator =1 Initiator=0
1 Send Receive
2 Receive Send
3 Send Receive
4 Receive Send