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 151 of 222
NXP Semiconductors
PN532/C1
Near Field Communication (NFC) controller
8.6.23.9 CIU_Status1 register (DFh or 6337h)
Contains status flags of the CRC, Interrupt Request System and FIFO buffer.
Table 190. CIU_Status1 register (address DFh or 6337h) bit allocation
Bit 7 6 5 4 3 2 1 0
Symbol CIU_IRQ_
1
CRCOk CRCReady CIU_IRQ
_0
TRunning RFOn HiAlert LoAlert
Reset 00 1 0 0X01
Access RR R R RRRR
Table 191. Description of CIU_Status1 bits
Bit Symbol Description
7 CIU_IRQ_1 This bit shows, if any CIU_IRQ_1 source requests attention (with respect to the
setting of the interrupt enable flags, see CIU_CommIEn and CIU_DivIEn
registers).
The bit IE1_2 of register IE1 (see Table 13 on page 18
) has to be set to logic 1 to
enable the corresponding CPU interrupt.
6 CRCOk Set to logic 1, the CRC result is zero. For data transmission and reception the bit
CRCOk is undefined (use CRCErr in CIU_Error register). CRCok indicates the
status of the CRC coprocessor, during calculation the value changes to logic 0,
when the calculation is done correctly, the value changes to logic 1.
5 CRCReady Set to logic 1, when the CRC calculation has finished. This bit is only valid for the
CRC co-processor calculation using the CalcCRC command.
4 CIU_IRQ_0 This bit shows, if any CIU_IRQ_0 source requests attention (with respect to the
setting of the interrupt enable flags, see CIU_CommIEn and CIU_DivIEn
registers).
The bit IE1_3 of register IE1 (see Table 13 on page 18
) has to be set to logic 1 to
enable the corresponding CPU interrupt.
3 TRunning Set to logic 1, the CIU_timer is running, e.g. the CIU_timer will decrement the
CIU_TCounterVal_lo with the next timer clock.
Note: In the gated mode TRunning is set to logic 1, when the CIU_timer is
enabled by the register bits. This bit is not influenced by the gated signal.
2 RFOn Set to logic 1, if an external RF field is detected. This bit does not store the state
of the RF field.
1 HiAlert Set to logic 1, when the number of bytes stored in the FIFO buffer fulfils the
following equation:
Example:
0 LoAlert Set to logic 1, when the number of bytes stored in the FIFO buffer fulfills the
following equation:
Example:
HiAlert 64 FIFOLength–WaterLevel=
FIFOLenght 60 WaterLevel 4==HiAlert 1=
FIFOLenght 59 WaterLevel 4==HiAlert 0=
LoAlert FIFOLength WaterLevel=
FIFOLenght 4 WaterLevel 4==LoAlert 1=
FIFOLenght 5 WaterLevel 4==LoAlert 0=