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 154 of 222
NXP Semiconductors
PN532/C1
Near Field Communication (NFC) controller
8.6.23.13 CIU_WaterLevel register (ECh or 633Bh)
Defines the thresholds for FIFO under- and overflow warning.
8.6.23.14 CIU_Control register (EDh or 633Ch)
Contains miscellaneous control bits.
Table 198. CIU_WaterLevel register (address ECh or 633Bh) bit allocation
Bit 7 6 5 4 3 2 1 0
Symbol - - WaterLevel[6:0]
Reset 00001000
Access R R R/WR/WR/WR/WR/WR/W
Table 199. Description of CIU_WaterLevel bits
Bit Symbol Description
7 to 6 - Reserved.
5 to 0 WaterLevel[5:0] This register defines a threshold to indicate a FIFO buffer over- or
underflow to the 80C51:
The HiAlert bit in CIU_Status1 register is set to logic 1, if the remaining
number of bytes in the FIFO-buffer space is equal or less than the
defined WaterLevel[5:0] bits.
The LoAlert bit in CIU_Status1 register is set to logic 1, if equal or less
than WaterLevel[5:0] bits are in the FIFO.
Remark: For the calculation of the HiAlert and LoAlert see Table 19 1
on page 151.
Table 200. CIU_Control register (address EDh or 633Ch) bit allocation
Bit 7 6 5 4 3 2 1 0
Symbol TStopNow TStartNow WrNFCIP-1IDtoFIFO Initiator - RxLastBits[2:0]
Reset 0 0 0 0 0000
Access W W DY R/WRRRR
Table 201. Description of CIU_Control bits
Bit Symbol Description
7 TStopNow Set to logic 1, the timer stops immediately.
Reading this bit will always return logic 0.
6 TStartNow Set to logic 1, the timer starts immediately.
Reading this bit will always return logic 0.
5 WrNFCIP-1IDtoFIFO Set to logic 1, the internal stored NFCID3 (10 bytes) is copied into
the FIFO.
Afterwards the bit is set to logic 0 automatically
4 Initiator Set to logic 1, the PN532 acts as Initiator or Reader/Writer,
otherwise it acts as Target. or a Card.
3 - Reserved.
2 to 0 RxLastBits[2:0] Shows the number of valid bits in the last received byte. If set to
000b, the whole byte is valid.