
CLRC632_35
NXP B.V. 2009. All rights reserved.
Product data sheet
PUBLIC
Rev. 3.5 — 10 November 2009
073935
71 of 126
NXP Semiconductors
CLRC632
Multiple protocol contactless reader IC (MIFARE/I-CODE1)
10.5.6 Page 5: FIFO, timer and IRQ pin conguration
10.5.6.1
Page register
10.5.6.2
FIFOLevel register
Denes the levels for FIFO underow and overow warning.
10.5.6.3
TimerClock register
Selects the divider for the timer clock.
Table 112. FIFOLevel register (address: 29h) reset value: 0000 1000b, 08h bit allocation
Bit
7
6
5
4
3
2
1
0
Symbol
00
WaterLevel[5:0]
Access
R/W
Table 113. FIFOLevel register bit descriptions
Bit
Symbol
Description
7 to 6 00
these values must not be changed
5 to 0 WaterLevel[5:0] denes, the warning level of a FIFO buffer overow or underow:
HiAlert is set to logic 1 if the remaining FIFO buffer space is equal to,
or less than, WaterLevel[5:0] bits in the FIFO buffer.
LoAlert is set to logic 1 if equal to, or less than, WaterLevel[5:0] bits in
the FIFO buffer.
Table 114. TimerClock register (address: 2Ah) reset value: 0000 0111b, 07h bit allocation
Bit
7
6
5
4
3
2
1
0
Symbol
00
TAutoRestart
TPreScaler[4:0]
Access
RW
Table 115. TimerClock register bit descriptions
Bit
Symbol
Value
Function
7 to 6
00
-
these values must not be changed
5
TAutoRestart
1
the timer automatically restarts its countdown from the
TReloadValue[7:0] instead of counting down to zero
0
the timer decrements to zero and register InterruptIrq
TimerIRq bit is set to logic 1
4 to 0
TPreScaler[4:0]
-
denes the timer clock frequency (fTimerClock). The
TPreScaler[4:0] can be adjusted from 0 to 21. The following
formula is used to calculate the TimerClock frequency
(fTimerClock):
fTimerClock = 13.56 MHz / 2TPreScaler [MHz]