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 132 of 222
NXP Semiconductors
PN532/C1
Near Field Communication (NFC) controller
8.6.19 CIU Power Reduction Modes
8.6.19.1 Hard-Power-Down
A Hard-Power-Down is enabled when RSTPD_N is low. None of the CIU blocks are
running, even the RF level detector.
8.6.19.2 CIU Power-down
The CIU Power-down mode is entered immediately by setting the Power-down bit in the
register CIU_Command. All CIU blocks are switched off, except the 27.12 MHz oscillator
and the RF level detector.
All registers and the FIFO will keep the content during CIU Power-down.
If the bit AutoWakeUp in the register CIU_TxAuto is set and an external RF field is
detected, the CIU Power-down mode is left automatically.
After setting bit Power-down to logic 0 in the register CIU_Command, it needs 1024 clocks
cycle until the CIU Power-down mode is left indicated by the Power-down bit itself. Setting
it to logic 0 does not immediately set it to logic 0. It is automatically set to logic 0 by the
CIU when the CIU Power-down mode is left.
When in CIU Power-down mode and DriverSel[1:0] is no set to 00b (see Table 217 on
page 162), to ensure a minimum impedance at the transmitter outputs, the CWGsNOn[3],
CWGsNOff[3], ModGsNOn[3], ModGsNOff[3], CWGsP[5], ModGsP[5] bits are set to logic
1, but it is not readable in the registers.
Table 165. High priority interrupt sources (CIU_IRQ_0)
Interrupt Flag Interrupt source Set automatically, WHEN
TxIRq Transmitter a transmitted data stream ends
RxIRq Receiver a received data stream ends
HiAlertIRq FIFO-buffer the FIFO-buffer is getting full
LoAlertIRq FIFO-buffer the FIFO-buffer is getting empty
Table 166. Low priority interrupt sources (CIU_IRQ_1)
Interrupt Flag Interrupt source Set automatically, WHEN
TimerIRq Timer Unit the timer counts from 1 to 0
CRCIRq CRC-Coprocessor all data from the FIFO buffer have been processed
IdleIRq CIU_Command
Register
a command execution finishes
RFOnIRq RF Level Detector an external RF field is detected
RFOffIRq RF Level Detector a present external RF field is switched off
ErrIRq CIU an error is detected
ModeIRq data mode detector the mode has been detected